University of Michigan Hydrodynamics | Open Energy Information
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Universal holographic hydrodynamics at finite coupling
Alex Buchel; Robert C. Myers; Miguel F. Paulos; Aninda Sinha
2008-09-12T23:59:59.000Z
We consider thermal plasmas in a large class of superconformal gauge theories described by a holographic dual geometry of the form $AdS_5\\times M_5$. In particular, we demonstrate that all of the thermodynamic properties and hydrodynamic transport parameters for a large class of superconformal gauge theories exhibit a certain universality to leading order in the inverse 't Hooft coupling and $1/N_c$. In particular, we show that independent of the compactification geometry, the leading corrections are derived from the same five-dimensional effective supergravity action supplemented by a term quartic in the five-dimensional Weyl tensor.
University of Minnesota Hydrodynamics | Open Energy Information
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Cornell University Hydrodynamics | Open Energy Information
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University of Maine Hydrodynamics | Open Energy Information
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University of New Hampshire Hydrodynamics | Open Energy Information
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Jump in fluid properties of inflationary universe to reconcile scalar and tensor spectra
Hassan Firouzjahi; Mohammad Hossein Namjoo
2014-04-09T23:59:59.000Z
The recent detection of the primordial gravitational waves from the BICEP2 observation seems to be in tension with the upper bound on the amplitude of tensor perturbations from the PLANCK data. We consider a phenomenological model of inflation in which the microscopical properties of the inflationary fluid such as the equation of state $w$ or the sound speed $c_s$ jump in a sharp manner. We show that the amplitude of the scalar perturbations is controlled by a non-trivial combination of $w$ and $c_s$ before and after the phase transition while the tensor perturbations remains nearly intact. With an appropriate choice of the fluid parameters $w$ and $c_s$ one can suppress the scalar perturbation power spectrum on large scales to accommodate a large tensor amplitude with $r=0.2$ as observed by BICEP2 observation.
Jump in fluid properties of inflationary universe to reconcile scalar and tensor spectra
Firouzjahi, Hassan
2014-01-01T23:59:59.000Z
The recent detection of the primordial gravitational waves from the BICEP2 observation seems to be in tension with the upper bound on the amplitude of tensor perturbations from the PLANCK data. We consider a phenomenological model of inflation in which the microscopical properties of the inflationary fluid such as the equation of state $w$ or the sound speed $c_s$ jump in a sharp manner. We show that the amplitude of the scalar perturbations is controlled by a non-trivial combination of $w$ and $c_s$ before and after the phase transition while the tensor perturbations remains nearly intact. With an appropriate choice of the fluid parameters $w$ and $c_s$ one can suppress the scalar perturbation power spectrum on large scales to accommodate a large tensor amplitude with $r=0.2$ as observed by BICEP2 observation.
Assessing Thermo-Hydrodynamic-Chemical Processes at the Dixie...
Transport Modeling Approach Jump to: navigation, search OpenEI Reference LibraryAdd to library Conference Paper: Assessing Thermo-Hydrodynamic-Chemical Processes at the Dixie...
MHK Projects/Marine Hydrodynamics Laboratory at the University of Michigan
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov YouKizildere I Geothermal Pwer Plant Jump to:LandownersLuther, Oklahoma: EnergyMARECInformationGriffinCABendMakai
Hydraulic/Shock-Jumps in Protoplanetary Disks
A. C. Boley; R. H. Durisen
2006-03-10T23:59:59.000Z
In this paper, we describe the nonlinear outcome of spiral shocks in protoplanetary disks. Spiral shocks, for most protoplanetary disk conditions, create a loss of vertical force balance in the post-shock region and result in rapid expansion of the gas perpendicular to the disk midplane. This expansion has characteristics similar to hydraulic jumps, which occur in incompressible fluids. We present a theory to describe the behavior of these hybrids between shocks and hydraulic jumps (shock bores) and then compare the theory to three-dimensional hydrodynamics simulations. We discuss the fully three-dimensional shock structures that shock bores produce and discuss possible consequences for disk mixing, turbulence, and evolution of solids.
Hydrodynamics of jumping in archer fish, Toxotes microlepis
Shih, Anna Margaret
2010-01-01T23:59:59.000Z
The maneuvering of fish is not only of interest to those wishing to better understand how fish function, but also is a great inspiration for designing underwater vehicles. This thesis provides the first characterization ...
Jump Starting GARCH: Pricing Options with Jumps in Returns and
Chaudhuri, Sanjay
Jump Starting GARCH: Pricing Options with Jumps in Returns and Volatilities J. Duan, P. Ritchken and volatilities. Our model nests Duan's GARCH option models where conditional returns are constrained to being normal, as well as extends Merton's jump-diffusion model by allowing return volatility to exhibit GARCH
Causal dissipative hydrodynamics for heavy ion collisions
Chaudhuri, A K
2011-01-01T23:59:59.000Z
We briefly discuss the recent developments in causal dissipative hydrodynamic for relativistic heavy ion collisions. Phenomenological estimate of QGP viscosity over entropy ratio from several experimental data, e.g. STAR's $\\phi$ meson data, centrality dependence of elliptic flow, universal scaling elliptic flow etc. are discussed. QGP viscosity, extracted from hydrodynamical model analysis can have very large systematic uncertainty due to uncertain initial conditions.
Causal dissipative hydrodynamics for heavy ion collisions
A. K. Chaudhuri
2011-01-23T23:59:59.000Z
We briefly discuss the recent developments in causal dissipative hydrodynamic for relativistic heavy ion collisions. Phenomenological estimate of QGP viscosity over entropy ratio from several experimental data, e.g. STAR's $\\phi$ meson data, centrality dependence of elliptic flow, universal scaling elliptic flow etc. are discussed. QGP viscosity, extracted from hydrodynamical model analysis can have very large systematic uncertainty due to uncertain initial conditions.
DATA ASSIMILATION IN HYDRODYNAMIC MODELS
modelling and Kalman filters. The thesis consists of a summary report and a collection of seven researchDATA ASSIMILATION IN HYDRODYNAMIC MODELS OF CONTINENTAL SHELF SEAS Jacob Viborg Tornfeldt Sørensen Informatics and Mathematical Modelling Technical University of Denmark Ph.D. Thesis No. 126 Kgs. Lyngby 2004
Jean-Luc Thiffeault; Andrew Belmonte
2010-09-01T23:59:59.000Z
When a fluid jet strikes an inclined solid surface at normal incidence, gravity creates a flow pattern with a thick outer rim resembling a parabola and reminiscent of a hydraulic jump. There appears to be little theory or experiments describing simple aspects of this phenomenon, such as the maximum rise height of the fluid above the impact point, and its dependence on jet velocity and inclination angle. We address this with experiments, and present a simple theory based on horizontal hydraulic jumps which accounts for the rise height and its scaling, though without describing the shape of the parabolic envelope.
Viscous Hydraulic Jumps Submitted by
Bush, John W.M.
Viscous Hydraulic Jumps Submitted by Jeffrey M. Aristoff, Jeffrey D. Leblanc, Annette E. Hosoi, and John W. M. Bush, Massachusetts Institute of Technology We examine the form of the viscous hydraulic of height 210 mm. Elegaard et al.1 first demonstrated that the axial symme- try of the viscous hydraulic
Numerical Study of a Turbulent Hydraulic Jump
Zhao, Qun
Numerical Study of a Turbulent Hydraulic Jump Qun Zhao, Shubhra Misra, Ib. A. Svendsen and James T of a Turbulent Hydraulic Jump p.1/14 #12;Objective Our ultimate goal is to study the breaking waves. Numerical Study of a Turbulent Hydraulic Jump p.2/14 #12;A moving bore Qiantang Bore China (Courtesy of Dr J
Hydrodynamics of vegetated channels
Nepf, Heidi
This paper highlights some recent trends in vegetation hydrodynamics, focusing on conditions within channels and spanning spatial scales from individual blades, to canopies or vegetation patches, to the channel reach. At ...
P. M. Stevenson
2005-07-30T23:59:59.000Z
Hydrodynamics is the appropriate "effective theory" for describing any fluid medium at sufficiently long length scales. This paper treats the vacuum as such a medium and derives the corresponding hydrodynamic equations. Unlike a normal medium the vacuum has no linear sound-wave regime; disturbances always "propagate" nonlinearly. For an "empty vacuum" the hydrodynamic equations are familiar ones (shallow water-wave equations) and they describe an experimentally observed phenomenon -- the spreading of a clump of zero-temperature atoms into empty space. The "Higgs vacuum" case is much stranger; pressure and energy density, and hence time and space, exchange roles. The speed of sound is formally infinite, rather than zero as in the empty vacuum. Higher-derivative corrections to the vacuum hydrodynamic equations are also considered. In the empty-vacuum case the corrections are of quantum origin and the post-hydrodynamic description corresponds to the Gross-Pitaevskii equation. I conjecture the form of the post-hydrodynamic corrections in the Higgs case. In the 1+1-dimensional case the equations possess remarkable `soliton' solutions and appear to constitute a new exactly integrable system.
Bubble visualization in a simulated hydraulic jump
Witt, Adam; Shen, Lian
2013-01-01T23:59:59.000Z
This is a fluid dynamics video of two- and three-dimensional computational fluid dynamics simulations carried out at St. Anthony Falls Laboratory. A transient hydraulic jump is simulated using OpenFOAM, an open source numerical solver. A Volume of Fluid numerical method is employed with a realizable k-epsilon turbulence model. The goal of this research is to model the void fraction and bubble size in a transient hydraulic jump. This fluid dynamics video depicts the air entrainment characteristics and bubble behavior within a hydraulic jump of Froude number 4.82.
JUMP DIFFUSION OPTION WITH TRANSACTION COSTS
Mocioalca, Oana
JUMP DIFFUSION OPTION WITH TRANSACTION COSTS "non-systematic" risk, inclusive of transaction costs. We compute the total transac- tion costs and the turnover for different options, transaction costs, and revision intervals
Hydrodynamic instability in strong media
Bakhrakh, S.M.; Drennov, O.B.; Kovalev, N.P. [Russian Federal Nuclear Center (Russian Federation)] [and others
1997-03-05T23:59:59.000Z
This paper reviews the All Russian Scientific Research Institute of Experimental Physics open publications on hydrodynamic instability in strong media.
Skew resisting hydrodynamic seal
Conroy, William T. (Pearland, TX); Dietle, Lannie L. (Sugar Land, TX); Gobeli, Jeffrey D. (Houston, TX); Kalsi, Manmohan S. (Houston, TX)
2001-01-01T23:59:59.000Z
A novel hydrodynamically lubricated compression type rotary seal that is suitable for lubricant retention and environmental exclusion. Particularly, the seal geometry ensures constraint of a hydrodynamic seal in a manner preventing skew-induced wear and provides adequate room within the seal gland to accommodate thermal expansion. The seal accommodates large as-manufactured variations in the coefficient of thermal expansion of the sealing material, provides a relatively stiff integral spring effect to minimize pressure-induced shuttling of the seal within the gland, and also maintains interfacial contact pressure within the dynamic sealing interface in an optimum range for efficient hydrodynamic lubrication and environment exclusion. The seal geometry also provides for complete support about the circumference of the seal to receive environmental pressure, as compared the interrupted character of seal support set forth in U.S. Pat. Nos. 5,873,576 and 6,036,192 and provides a hydrodynamic seal which is suitable for use with non-Newtonian lubricants.
University of Nebraska-Lincoln and University of Florida (Building...
Nebraska-Lincoln and University of Florida (Building Energy Efficient Homes for America) Jump to: navigation, search Name: University of Nebraska-Lincoln and University of Florida...
The hydraulic jump as a white hole
G. E. Volovik
2005-10-21T23:59:59.000Z
In the geometry of the circular hydraulic jump, the velocity of the liquid in the interior region exceeds the speed of capillary-gravity waves (ripplons), whose spectrum is `relativistic' in the shallow water limit. The velocity flow is radial and outward, and thus the relativistic ripplons cannot propagating into the interior region. In terms of the effective 2+1 dimensional Painleve-Gullstrand metric appropriate for the propagating ripplons, the interior region imitates the white hole. The hydraulic jump represents the physical singularity at the white-hole horizon. The instability of the vacuum in the ergoregion inside the circular hydraulic jump and its observation in recent experiments on superfluid 4He by E. Rolley, C. Guthmann, M.S. Pettersen and C. Chevallier in physics/0508200 are discussed.
A Model For Polygonal Hydraulic Jumps
Martens, Erik A; Bohr, Tomas
2011-01-01T23:59:59.000Z
We propose a phenomenological model for the polygonal hydraulic jumps discovered by Ellegaard et al., based on the known flow structure for the type II hydraulic jumps with a "roller" (separation eddy) near the free surface in the jump region. The model consists of mass conservation and radial force balance between hydrostatic pressure and viscous stresses on the roller surface. In addition, we consider the azimuthal force balance, primarily between pressure and viscosity, but also including non-hydrostatic pressure contributions from surface tension in light of recent observations by Bush et al. The model can be analyzed by linearization around the circular state, resulting in a parameter relationship for nearly circular polygonal states. A truncated, but fully nonlinear version of the model can be solved analytically. This simpler model gives rise to polygonal shapes that are very similar to those observed in experiments, even though surface tension is neglected, and the condition for the existence of a pol...
Jump to first page Promoting Health,
Breastfeeding Poor Nutrition - Food Preferences Low physical activity Lack of sleep #12;Jump to first page protein during pregnancy, has strong implications for future metabolic health. Undernourished infant children 3 years later. Data from mother's diet history and umbilical cord blood The increase
Jump to first page American Planning Association
to first page How Smart is your Community? Small group exercise 5. CENTRAL CITY VITALITY Examples: GradeJump to first page American Planning Association Core Smart Growth Principles 1) INCREASED CITIZEN, adaptive re-use) 5) CENTRAL CITY VITALITY 6) GREATER MIX OF USES AND HOUSING CHOICES FOCUSED AROUND HUMAN
Load responsive hydrodynamic bearing
Kalsi, Manmohan S. (Houston, TX); Somogyi, Dezso (Sugar Land, TX); Dietle, Lannie L. (Stafford, TX)
2002-01-01T23:59:59.000Z
A load responsive hydrodynamic bearing is provided in the form of a thrust bearing or journal bearing for supporting, guiding and lubricating a relatively rotatable member to minimize wear thereof responsive to relative rotation under severe load. In the space between spaced relatively rotatable members and in the presence of a liquid or grease lubricant, one or more continuous ring shaped integral generally circular bearing bodies each define at least one dynamic surface and a plurality of support regions. Each of the support regions defines a static surface which is oriented in generally opposed relation with the dynamic surface for contact with one of the relatively rotatable members. A plurality of flexing regions are defined by the generally circular body of the bearing and are integral with and located between adjacent support regions. Each of the flexing regions has a first beam-like element being connected by an integral flexible hinge with one of the support regions and a second beam-like element having an integral flexible hinge connection with an adjacent support region. A least one local weakening geometry of the flexing region is located intermediate the first and second beam-like elements. In response to application of load from one of the relatively rotatable elements to the bearing, the beam-like elements and the local weakening geometry become flexed, causing the dynamic surface to deform and establish a hydrodynamic geometry for wedging lubricant into the dynamic interface.
Bell's Jump Process in Discrete Time
Jonathan Barrett; Matthew Leifer; Roderich Tumulka
2005-09-27T23:59:59.000Z
The jump process introduced by J. S. Bell in 1986, for defining a quantum field theory without observers, presupposes that space is discrete whereas time is continuous. In this letter, our interest is to find an analogous process in discrete time. We argue that a genuine analog does not exist, but provide examples of processes in discrete time that could be used as a replacement.
Effects on the Physical Environment (Hydrodynamics, Sediment...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Effects on the Physical Environment (Hydrodynamics, Sediment Transport, and Water Quality) Effects on the Physical Environment (Hydrodynamics, Sediment Transport, and Water...
Hydrodynamics of Holographic Superconductors
Irene Amado; Matthias Kaminski; Karl Landsteiner
2009-06-17T23:59:59.000Z
We study the poles of the retarded Green functions of a holographic superconductor. The model shows a second order phase transition where a charged scalar operator condenses and a U(1) symmetry is spontaneously broken. The poles of the holographic Green functions are the quasinormal modes in an AdS black hole background. We study the spectrum of quasinormal frequencies in the broken phase, where we establish the appearance of a massless or hydrodynamic mode at the critical temperature as expected for a second order phase transition. In the broken phase we find the pole representing second sound. We compute the speed of second sound and its attenuation length as function of the temperature. In addition we find a pseudo diffusion mode, whose frequencies are purely imaginary but with a non-zero gap at zero momentum. This gap goes to zero at the critical temperature. As a technical side result we explain how to calculate holographic Green functions and their quasinormal modes for a set of operators that mix under the RG flow.
Viscous Undular Hydraulic Jumps of Moderate Reynolds number
Shyamasundar, R.K.
Viscous Undular Hydraulic Jumps of Moderate Reynolds number Ratul Dasgupta I will present some results on undular hydraulic jumps occurring in a two bores (in rivers), where the interface remains horizontal, the moderate Reynolds hydraulic jump shows a linear increase in height due to viscosity
Anderson, Mary Elizabeth
2011-10-21T23:59:59.000Z
nor implemented in current hydrodynamic models. A series of laboratory experiments were conducted at the Haynes Coastal Engineering Laboratory and in a two-dimensional flume at Texas A and M University to investigate the influence of relative...
Lift-off dynamics in a simple jumping robot
Jeffrey Aguilar; Alex Lesov; Kurt Wiesenfeld; Daniel I. Goldman
2012-08-30T23:59:59.000Z
We study vertical jumping in a simple robot comprising an actuated mass-spring arrangement. The actuator frequency and phase are systematically varied to find optimal performance. Optimal jumps occur above and below (but not at) the robot's resonant frequency $f_0$. Two distinct jumping modes emerge: a simple jump which is optimal above $f_0$ is achievable with a squat maneuver, and a peculiar stutter jump which is optimal below $f_0$ is generated with a counter-movement. A simple dynamical model reveals how optimal lift-off results from non-resonant transient dynamics.
A cinematographical analysis of the action of the lead leg in the flop high jump
Smith, Carol J
1984-01-01T23:59:59.000Z
A CINEMATOGRAPHICAL ANALYSIS OF THE ACTION OF THE LEAD LEG IN THE FLOP HIGH JUMP A Thesis CAROL J. SMITH Submitted to the Graduate College of Texas ASM University in partial fulfillment of the requirement for the degree o MASTER OF SCIENCE... August 1984 Major Subject: Physical Education A CINEMATOGRAPHICAL ANALYSIS OF THE ACTION OF THE LEAD LEG IN THE FLOP HIGH JUMP A Thesis by CAROL J. SMITH Approved as to style and content by: Lin s J. Dowell (Chairman of Committee) Homer Toison...
Escape from the potential well: competition between long jumps and long waiting times
Bartlomiej Dybiec
2010-09-09T23:59:59.000Z
Within a concept of the fractional diffusion equation and subordination, the paper examines the influence of a competition between long waiting times and long jumps on the escape from the potential well. Applying analytical arguments and numerical methods, we demonstrate that the presence of long waiting times distributed according to a power-law distribution with a diverging mean leads to very general asymptotic properties of the survival probability. The observed survival probability asymptotically decays like a power-law whose form is not affected by the value of the exponent characterizing the power-law jump length distribution. It is demonstrated that this behavior is typical of and generic for systems exhibiting long waiting times. We also show that the survival probability has a universal character not only asymptotically but also at small times. Finally, it is indicated which properties of the first passage time density are sensitive to the exact value of the exponent characterizing the jump length distribution.
Greendyke, Robert Brian
1988-01-01T23:59:59.000Z
A PARAMETRIC STUDY OF SHOCK JUMP CHEMISTRY, ELECTRON TEMPERATURE, AND RADIATIVE HEAT TRANSFER MODELS IN HYPERSONIC FLOWS A Thesis by ROBERT BRIAN GREENDYKE Submitted to the Graduate College of Texas A&M University in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE August 1988 Major Subject: Aerospace Engineering A PARAMETRIC STUDY OF SHOCK JUMP CHEMISTRY, ELECTRON TEMPERATURE, AND RADIATIVE HEAT TRANSFER MODELS IN HYPERSONIC FLOWS A Thesis by ROBERT BRIAN...
Colorado State University Hydrodynamics | Open Energy Information
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are being directedAnnual Siteof EnergyInnovationin UrbanCityCoated ConductorsColonial Industria deof
Oregon State University Hydrodynamics | Open Energy Information
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are being directedAnnual SiteofEvaluatingGroup |JilinLuOpenNorthOlympia GreenThe communityOrchid Bioenergy
Pennsylvania State University Hydrodynamics | Open Energy Information
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are being directedAnnual SiteofEvaluatingGroup |JilinLuOpenNorthOlympiaAnalysis)Pearl
Formation Interuniversitaire de Physique Hydrodynamics
Balbus, Steven
Formation Interuniversitaire de Physique Module : Hydrodynamics S. Balbus 1 #12;TO LEARN.8.3 Piston Driven into Gas Cylinder . . . . . . . . . . . . . 73 4.8.4 Driven Acoustic Modes . . . . . . . . . . . . . . . . 110 6.2.3 Inertial Drag of a Sphere by an Ideal Fluid . . . . . . . 113 6.3 Line Vortices and Flow
Dynamical Spacetimes from Numerical Hydrodynamics
Allan Adams; Nathan Benjamin; Arvin Moghaddam; Wojciech Musial
2014-11-07T23:59:59.000Z
We numerically construct dynamical asymptotically-AdS$_4$ metrics by evaluating the fluid/gravity metric on numerical solutions of dissipative hydrodynamics in (2+1) dimensions. The resulting numerical metrics satisfy Einstein's equations in (3+1) dimensions to high accuracy.
Topological groundwater hydrodynamics Garrison Sposito
Chen, Yiling
Topological groundwater hydrodynamics Garrison Sposito Department of Civil and Environmental; received in revised form 10 November 2000; accepted 15 November 2000 Abstract Topological groundwater, the topological characteristics of groundwater ¯ows governed by the Darcy law are studied. It is demonstrated that
Hydrodynamic Lyapunov Modes in Translation Invariant Systems
Hydrodynamic Lyapunov Modes in Translation Invariant Systems JeanÂPierre Eckmann and Omri Gat De modes in the slowly growing part of the Lyapunov spectrum, which are analogous to the hydrodynamic modes)]. The hydrodynamic Lyapunov vectors loose the typical random structure and exhibit instead the structure of weakly
Hydrodynamic Lyapunov Modes in Translation Invariant Systems
Eckmann, Jean-Pierre
Hydrodynamic Lyapunov Modes in Translation Invariant Systems JeanPierre Eckmann and Omri Gat De modes in the slowly growing part of the Lyapunov spectrum, which are analogous to the hydrodynamic modes)]. The hydrodynamic Lyapunov vectors loose the typical random structure and exhibit instead the structure of weakly
ISSN 1745-9648 Gasoline Prices Jump Up on Mondays
Feigon, Brooke
ISSN 1745-9648 Gasoline Prices Jump Up on Mondays: an Outcome of Aggressive Competition? by Øystein Research Council is gratefully acknowledged. #12;Gasoline prices jump up on Mondays: An outcome, 2008 Abstract This paper examines Norwegian gasoline pump prices using daily station
Swing Options Valuation: a BSDE with Constrained Jumps Approach
Swing Options Valuation: a BSDE with Constrained Jumps Approach Marie Bernhart Huy^en Pham Peter Tankov Xavier Warin§ January 7, 2011 Abstract We introduce a new probabilistic method for solving a class (BSDEs for short) with constrained jumps. As an example, our method is used for pricing Swing options. We
Self-propelled jumping drops on superhydrophobic surfaces
Chen, Chuan-Hua
Self-propelled jumping drops on superhydrophobic surfaces Jonathan B. Boreyko and Chuan-Hua Chena-propelled jumping phenomenon for coa- lescing drops on superhydrophobic surfaces. The spontane- ous motion is powered by surface energy released upon coalescence.1,2 On a horizontal, chilled superhydrophobic surface
Hydrodynamics of bubble columns with application to Fischer-Tropsch synthesis
Raphael, Matheo Lue
1988-01-01T23:59:59.000Z
HYDRODYNAMICS OF BUBBLE COLUMNS AYITH APPLICATION TO FISCHER-TROPSCH SYNTHESIS A Thesis by- MATHEO LUE RAPHAEL Submitted to the Graduate College of Texas ARM University in partial fulfillment of the requirement for the degree of MASTER... OF SCIENCE May 1988 Major Subject: Chemical Engineering HYDRODYNAMICS OF BUBBLE COLUMNS WITH APPLICATION TO FISCHER-TROPSCH SYNTHESIS A Thesis by iAIATHEO LUE RAPHAEL Approved as to style and content by: D. B. Bukur Chairman of Com 'ttee) M. T. za...
Bicknell, James Scott
1985-01-01T23:59:59.000Z
DEPOSITIONAL ENVIRONMENT AND HYDRODYNAMIC FLOW IN LOWER CRETACEOUS J SANDSTONE, LONETREE FIELD, DENVER BASIN, COLORADO A Thesis by JAMES SCOTT BICKNELL Submitted to the Graduate College of Texas A&M University in partial fulfillment... of the requirement for the degree of MASTER OF SCIENCE December 1985 Major Subject: Geology DEPOSITIONAL ENVIRONMENT AND HYDRODYNAMIC FLOW IN LOWER CRETACEOUS J SANDSTONE, LONETREE FIELD, DENVER BASIN, COLORADO A Thesis by JAMES SCOTT BICKNELL Approved...
Numerical Simulation of the Hydrodynamical Combustion to Strange Quark Matter
Brian Niebergal; Rachid Ouyed; Prashanth Jaikumar
2010-08-27T23:59:59.000Z
We present results from a numerical solution to the burning of neutron matter inside a cold neutron star into stable (u,d,s) quark matter. Our method solves hydrodynamical flow equations in 1D with neutrino emission from weak equilibrating reactions, and strange quark diffusion across the burning front. We also include entropy change due to heat released in forming the stable quark phase. Our numerical results suggest burning front laminar speeds of 0.002-0.04 times the speed of light, much faster than previous estimates derived using only a reactive-diffusive description. Analytic solutions to hydrodynamical jump conditions with a temperature dependent equation of state agree very well with our numerical findings for fluid velocities. The most important effect of neutrino cooling is that the conversion front stalls at lower density (below approximately 2 times saturation density). In a 2-dimensional setting, such rapid speeds and neutrino cooling may allow for a flame wrinkle instability to develop, possibly leading to detonation.
CONFINEMENT BY BIASED VELOCITY JUMPS: AGGREGATION OF ESCHERICHIA COLI
Schmeiser, Christian
by a jump process or by Brownian motion combined with accel- eration by the force field produced]. In this work a related type of particle dynamics is considered, where confinement is achieved by a biased
Jumping-Droplet-Enhanced Condensation on Scalable Superhydrophobic Nanostructured Surfaces
Miljkovic, Nenad
When droplets coalesce on a superhydrophobic nanostructured surface, the resulting droplet can jump from the surface due to the release of excess surface energy. If designed properly, these superhydrophobic nanostructured ...
Spontaneous Jumping of Coalescing Drops on a Superhydrophobic Surface
Boreyko, Jonathan
2009-01-01T23:59:59.000Z
When micrometric drops coalesce in-plane on a superhydrophobic surface, a surprising out-of-plane jumping motion was observed. Such jumping motion triggered by drop coalescence was reproduced on a Leidenfrost surface. High-speed imaging revealed that this jumping motion results from the elastic interaction of the bridged drops with the superhydrophobic/Leidenfrost surface. Experiments on both the superhydrophobic and Leidenfrost surfaces compare favorably to a simple scaling model relating the kinetic energy of the merged drop to the surface energy released upon coalescence. The spontaneous jumping motion on water repellent surfaces enables the autonomous removal of water condensate independently of gravity; this process is highly desirable for sustained dropwise condensation.
Jumping Droplet Dynamics on Scalable Nanostructured Superhydrophobic Surfaces
Miljkovic, Nenad
Environmental scanning electron microscope (ESEM) and high speed images of coalescence-induced droplet jumping on a nanostructured superhydrophobic copper oxide (CuO) surface are presented. Nanostructured CuO films were ...
Gravity-free hydraulic jumps and metal femtocups
Rama Govindarajan; Manikandan Mathur; Ratul DasGupta; N. R. Selvi; Neena Susan John; G. U. Kulkarni
2006-10-03T23:59:59.000Z
Hydraulic jumps created by gravity are seen every day in the kitchen sink. We show that at small scales a circular hydraulic jump can be created in the absence of gravity, by surface tension. The theory is motivated by our experimental finding of a height discontinuity in spreading submicron molten metal droplets created by pulsed-laser ablation. By careful control of initial conditions, we show that this leads to solid femtolitre cups of gold, silver, copper, niobium and tin.
Foundation of Hydrodynamics of Strongly Interacting Systems
Wong, Cheuk-Yin [ORNL] [ORNL
2014-01-01T23:59:59.000Z
Hydrodynamics and quantum mechanics have many elements in common, as the density field and velocity fields are common variables that can be constructed in both descriptions. Starting with the Schroedinger equation and the Klein-Gordon for a single particle in hydrodynamical form, we examine the basic assumptions under which a quantum system of particles interacting through their mean fields can be described by hydrodynamics.
Annual Report: Hydrodynamics and Radiative Hydrodynamics with Astrophysical Applications
R. Paul Drake
2005-12-01T23:59:59.000Z
We report the ongoing work of our group in hydrodynamics and radiative hydrodynamics with astrophysical applications. During the period of the existing grant, we have carried out two types of experiments at the Omega laser. One set of experiments has studied radiatively collapsing shocks, obtaining high-quality scaling data using a backlit pinhole and obtaining the first (ever, anywhere) Thomson-scattering data from a radiative shock. Other experiments have studied the deeply nonlinear development of the Rayleigh-Taylor (RT) instability from complex initial conditions, obtaining the first (ever, anywhere) dual-axis radiographic data using backlit pinholes and ungated detectors. All these experiments have applications to astrophysics, discussed in the corresponding papers either in print or in preparation. We also have obtained preliminary radiographs of experimental targets using our x-ray source. The targets for the experiments have been assembled at Michigan, where we also prepare many of the simple components. The above activities, in addition to a variety of data analysis and design projects, provide good experience for graduate and undergraduates students. In the process of doing this research we have built a research group that uses such work to train junior scientists.
Dual Axis Radiographic Hydrodynamic Test Facility | National...
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Dual Axis Radiographic Hydrodynamic Test Facility | National Nuclear Security Administration Facebook Twitter Youtube Flickr RSS People Mission Managing the Stockpile Preventing...
Hydrodynamic experiment conducted in Nevada | National Nuclear...
National Nuclear Security Administration (NNSA)
Leda involve non-nuclear surrogate materials that mimic many of the properties of nuclear materials. Hydrodynamics refers to the physics involved when solids, under extreme...
Ergoregion instability: The hydrodynamic vortex
Leandro A. Oliveira; Vitor Cardoso; Luís C. B. Crispino
2014-05-16T23:59:59.000Z
Four-dimensional, asymptotically flat spacetimes with an ergoregion but no horizon have been shown to be linearly unstable against a superradiant-triggered mechanism. This result has wide implications in the search for astrophysically viable alternatives to black holes, but also in the understanding of black holes and Hawking evaporation. Here we investigate this instability in detail for a particular setup which can be realized in the laboratory: the {\\it hydrodynamic vortex}, an effective geometry for sound waves, with ergoregion and without an event horizon.
Disruptive Innovation in Numerical Hydrodynamics
Waltz, Jacob I. [Los Alamos National Laboratory
2012-09-06T23:59:59.000Z
We propose the research and development of a high-fidelity hydrodynamic algorithm for tetrahedral meshes that will lead to a disruptive innovation in the numerical modeling of Laboratory problems. Our proposed innovation has the potential to reduce turnaround time by orders of magnitude relative to Advanced Simulation and Computing (ASC) codes; reduce simulation setup costs by millions of dollars per year; and effectively leverage Graphics Processing Unit (GPU) and future Exascale computing hardware. If successful, this work will lead to a dramatic leap forward in the Laboratory's quest for a predictive simulation capability.
Numerical integration of thermal noise in relativistic hydrodynamics
Clint Young
2013-06-03T23:59:59.000Z
Thermal fluctuations affect the dynamics of systems near critical points, the evolution of the early universe, and two-particle correlations in heavy-ion collisions. For the latter, numerical simulations of nearly-ideal, relativistic fluids are necessary. The correlation functions of noise in relativistic fluids are calculated, stochastic integration of the noise in 3+1-dimensional viscous hydrodynamics is implemented, and the effect of noise on observables in heavy-ion collisions is discussed. Thermal fluctuations will cause significant variance in the event-by-event distributions of integrated v2 while changing average values even when using the same initial conditions, suggesting that including thermal noise will lead to refitting of the hydrodynamical parameters with implications for understanding the physics of hot QCD.
Hydrodynamic forces on piggyback pipelines
Jakobsen, M.L.; Sayer, P. [Univ. of Strathclyde, Glasgow (United Kingdom)
1995-12-31T23:59:59.000Z
An increasing number of new offshore pipelines have been designed as bundles, mainly because of overall cost reductions. One popular way of combining two pipelines with different diameters is the piggyback configuration, with the smaller pipeline strapped on top of the main pipeline. The external hydrodynamic forces on this combination are at present very roughly estimated; pipeline engineers need more data to support their designs. This paper presents experimental results for the in-line hydrodynamic loading on three different piggyback set-ups. The models comprised a 0.4 m main pipeline, and three piggyback pipelines with diameters of 0.038 m, 0.059 m and 0.099 m. Each small pipeline was separately mounted to the main pipeline, with a gap equal to its own diameter. These model sizes lie approximately between half- and full-scale. Experiments were undertaken for K{sub C} between 5 and 42, and R{sub e} in the range 0.0 * 10{sup 4} to 8.5 * 10{sup 5}. The results based on Morison`s equation indicate that a simple addition of the separate forces acting on each cylinder underestimates the actual force by up to 35% at low K{sub C} (< {approximately} 10) and by as much as 100% in the drag-dominated regime (K{sub C} > {approximately} 20).
New Mexico State University District Heating Low Temperature...
New Mexico State University District Heating Low Temperature Geothermal Facility Jump to: navigation, search Name New Mexico State University District Heating Low Temperature...
Cape Peninsula University of Technology - Centre for Distributed...
Cape Peninsula University of Technology - Centre for Distributed Power and Electronic Systems Jump to: navigation, search Name: Cape Peninsula University of Technology Address:...
Anthropic prediction for a large multi-jump landscape
Delia Schwartz-Perlov
2008-09-04T23:59:59.000Z
The assumption of a flat prior distribution plays a critical role in the anthropic prediction of the cosmological constant. In a previous paper we analytically calculated the distribution for the cosmological constant, including the prior and anthropic selection effects, in a large toy ``single-jump'' landscape model. We showed that it is possible for the fractal prior distribution we found to behave as an effectively flat distribution in a wide class of landscapes, but only if the single jump size is large enough. We extend this work here by investigating a large ($N \\sim 10^{500}$) toy ``multi-jump'' landscape model. The jump sizes range over three orders of magnitude and an overall free parameter $c$ determines the absolute size of the jumps. We will show that for ``large'' $c$ the distribution of probabilities of vacua in the anthropic range is effectively flat, and thus the successful anthropic prediction is validated. However, we argue that for small $c$, the distribution may not be smooth.
Hydrodynamic Modeling and the QGP Shear Viscosity
Huichao Song
2012-07-10T23:59:59.000Z
In this article, we will briefly review the recent progress on hydrodynamic modeling and the extraction of the quark-gluon plasma (QGP) specific shear viscosity with an emphasis on results obtained from the hybrid model VISHNU that couples viscous hydrodynamics for the macroscopic expansion of the QGP to the hadron cascade model for the microscopic evolution of the late hadronic stage.
Energy Gradient Theory of Hydrodynamic Instability
Hua-Shu Dou
2005-01-29T23:59:59.000Z
A new universal theory for flow instability and turbulent transition is proposed in this study. Flow instability and turbulence transition have been challenging subjects for fluid dynamics for a century. The critical condition of turbulent transition from theory and experiments differs largely from each other for Poiseuille flows. In this paper, a new mechanism of flow instability and turbulence transition is presented for parallel shear flows and the energy gradient theory of hydrodynamic instability is proposed. It is stated that the total energy gradient in the transverse direction and that in the streamwise direction of the main flow dominate the disturbance amplification or decay. A new dimensionless parameter K for characterizing flow instability is proposed for wall bounded shear flows, which is expressed as the ratio of the energy gradients in the two directions. It is thought that flow instability should first occur at the position of Kmax which may be the most dangerous position. This speculation is confirmed by Nishioka et al's experimental data. Comparison with experimental data for plane Poiseuille flow and pipe Poiseuille flow indicates that the proposed idea is really valid. It is found that the turbulence transition takes place at a critical value of Kmax of about 385 for both plane Poiseuille flow and pipe Poiseuille flow, below which no turbulence will occur regardless the disturbance. More studies show that the theory is also valid for plane Couette flows and Taylor-Couette flows between concentric rotating cylinders.
Vacuum energy: quantum hydrodynamics vs quantum gravity
G. E. Volovik
2005-09-09T23:59:59.000Z
We compare quantum hydrodynamics and quantum gravity. They share many common features. In particular, both have quadratic divergences, and both lead to the problem of the vacuum energy, which in the quantum gravity transforms to the cosmological constant problem. We show that in quantum liquids the vacuum energy density is not determined by the quantum zero-point energy of the phonon modes. The energy density of the vacuum is much smaller and is determined by the classical macroscopic parameters of the liquid including the radius of the liquid droplet. In the same manner the cosmological constant is not determined by the zero-point energy of quantum fields. It is much smaller and is determined by the classical macroscopic parameters of the Universe dynamics: the Hubble radius, the Newton constant and the energy density of matter. The same may hold for the Higgs mass problem: the quadratically divergent quantum correction to the Higgs potential mass term is also cancelled by the microscopic (trans-Planckian) degrees of freedom due to thermodynamic stability of the whole quantum vacuum.
Effects on the Physical Environment (Hydrodynamics, and Water...
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and Water Quality Food Web) Effects on the Physical Environment (Hydrodynamics, and Water Quality Food Web) Effects on the Physical Environment (Hydrodynamics, and Water Quality...
A smoothed particle hydrodynamics model for reactive transport...
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A smoothed particle hydrodynamics model for reactive transport and mineral precipitation in porous and fractured porous media. A smoothed particle hydrodynamics model for reactive...
Stabilising entanglement by quantum jump-based feedback
A. R. R. Carvalho; J. J. Hope
2007-05-24T23:59:59.000Z
We show that direct feedback based on quantum jump detection can be used to generate entangled steady states. We present a strategy that is insensitive to detection inefficiencies and robust against errors in the control Hamiltonian. This feedback procedure is also shown to overcome spontaneous emission effects by stabilising states with high degree of entanglement.
ASYMPTOTIC EQUIVALENCE FOR INHOMOGENEOUS JUMP DIFFUSION PROCESSES AND WHITE NOISE.
Paris-Sud XI, Université de
ASYMPTOTIC EQUIVALENCE FOR INHOMOGENEOUS JUMP DIFFUSION PROCESSES AND WHITE NOISE. ESTER MARIUCCI Laboratoire Jean Kuntzmann, Grenoble. Abstract. We prove the global asymptotic equivalence between the experi. These asymptotic equivalences are established by constructing explicit Markov kernels that can be used to reproduce
Hydrodynamic compressibility of high-strength ceramics
Grady, D.E.
1993-08-01T23:59:59.000Z
In this study we have developed the techniques to investigate the hydrodynamic response of high-strength ceramics by mixing these powders with copper powder, preparing compacts, and performing shock compression tests on these mixtures. Hydrodynamics properties of silicon carbide, titanium diboride, and boron carbide to 30 GPa were examined by this method, and hydrodynamic compression data for these ceramics have been determined. We have concluded, however, that the measurement method is sensitive to sample preparation and uncertainties in shock wave measurements. Application of the experimental technique is difficult and further efforts are needed.
Solving the viscous hydrodynamics order by order
Jian-Hua Gao; Shi Pu
2014-09-02T23:59:59.000Z
In this paper, we propose a method of solving the viscous hydrodynamics order by order in a derivative expansion. In such method, the zero order solution is just the one of the ideal hydrodynamics. All the other higher order corrections satisfy the same first-order partial differential equations but with different inhomogeneous terms. We therefore argue that our method could be easily extended to any orders. The problem of causality and stability will be released if the gradient expansion is guaranteed. This method might be of great help to both theoretical and numerical calculations of relativistic hydrodynamics.
AGS tune jump system to cross horizontal depolarization resonances overview
Glenn, J.W.; Ahrens, L.; Fu, W.; Mi, J.L.; Rosas, P.; Schoefer, V.; Theisen, C.; Altinbas, Z.
2011-03-28T23:59:59.000Z
Two partial snakes overcome the vertical depolarizing resonances in the AGS. But a new type of depolarizing intrinsic resonance from horizontal motion appeared. We reduce these using horizontal tune jumps timed to these resonances. We gain a factor of six in crossing rate with a tune jump of 0.05 in 100 {micro}s. Two quadrapoles, we described in 2009, pulse 42 times, the current matching beam energy. The power supplies for these quads are described in detail elsewhere in this conference. The controls for the Jump Quad system is based on a BNL designed Quad Function Generator. Two modules are used; one for timing, and one to supply reference voltages. Synchronization is provided by a proprietary serial bus, the Event Link. The AgsTuneJump application predicts the times of the resonances during the AGS cycle and calculates the power supply trigger times from externally collected tune and energy versus time data and the Low and High PS voltage functions from a voltage to current model of the power supply. The system was commissioned during runs 09 & 10 and is operational. Many beam effects are described elsewhere. The TuneJump system has worked well and has caused little trouble save for the perturbations in the lattice having such a large effect due to our need to run with the vertical tune within a few thousandths of the integer tune. As these problems were mostly sorted out by correcting the 6th harmonic orbit distortions which caused a large 18 theta beta wave. Also running with minimal chromaticity reduces emittance growth. There are still small beta waves which are being addressed. The timing of the pulses is still being investigated, but as each crossing causes minimal polarization loss, this is a lengthy process.
Jump-Di usion Stock Return Models in Finance: Stochastic Process Density with Uniform-Jump Amplitude
Hanson, Floyd B.
-time, geometric, jump-di usion stochastic di erential equation (SDE), dS(t) = S(t) ddt + ddZ(t) + J(Q)dP (t)] S(0 and are constants. The di erential di usion process with drift ddt + ddZ(t) is has mean ddt and ddt variance
Experiments on wind-perturbed rogue wave hydrodynamics using the Peregrine breather model
Boyer, Edmond
Engineering, Imperial College London, London SW7 2AZ, United Kingdom 2 Dynamics Group, Hamburg University on the surface that results in a flux of energy from the wind to the waves and (ii) it generates a rotationalExperiments on wind-perturbed rogue wave hydrodynamics using the Peregrine breather model A
Pedersen, Tom
Turbines by Michael Robert Shives B.Eng., Carleton University, 2008 A Dissertation Submitted in Partial Hydrodynamic Modeling, Optimization and Performance Assessment for Ducted and Non-ducted Tidal Turbines) #12;iii ABSTRACT This thesis examines methods for designing and analyzing kinetic turbines based
Victoria, University of
Turbines by Michael Robert Shives B.Eng., Carleton University, 2008 A Thesis Submitted in Partial Hydrodynamic Modeling, Optimization and Performance Assessment for Ducted and Non-ducted Tidal Turbines examines methods for designing and analyzing kinetic turbines based on blade element momentum (BEM) theory
Analysis and Improvements of Fringe Jump Corrections by Electronics on the JET Tokamak FIR Interferometer
Shear viscosity, cavitation and hydrodynamics at LHC
Jitesh R. Bhatt; Hiranmaya Mishra; V. Sreekanth
2011-09-28T23:59:59.000Z
We study evolution of quark-gluon matter in the ultrarelativistic heavy-ion collisions within the frame work of relativistic second-order viscous hydrodynamics. In particular, by using the various prescriptions of a temperature-dependent shear viscosity to the entropy ratio, we show that the hydrodynamic description of the relativistic fluid become invalid due to the phenomenon of cavitation. For most of the initial conditions relevant for LHC, the cavitation sets in very early during the evolution of the hydrodynamics in time $\\lesssim 2 $fm/c. The cavitation in this case is entirely driven by the large values of shear viscosity. Moreover we also demonstrate that the conformal term used in equations of the relativistic dissipative hydrodynamic can influence the cavitation time.
Rioux, Frank
Quantum Jumps for an Electron in a One-dimensional Box The phrases "quantum jump" and "quantum leap by the nature of the process by which a quantum system passes from one allowed energy state to another. McMillin [J. Chem. Ed. 55, 7 (1978)] has described an appealing model for "quantum jumps" that is referred
Thermo--hydrodynamics As a Field Theory
Jacek Jezierski; Jerzy Kijowski
2011-12-26T23:59:59.000Z
The field theoretical description of thermo-hydrodynamics is given. It is based on the duality between the physical space--time and the "material space-time" which we construct here. The material space appearing in a natural way in the canonical formulation of the hydrodynamics is completed with a material time playing role of the field potential for temperature. Both Lagrangian and Hamiltonian formulations, the canonical structure, Poisson bracket, N\\"other theorem and conservation laws are discussed.
Heat release by controlled continuous-time Markov jump processes
Paolo Muratore-Ginanneschi; Carlos Mejía-Monasterio; Luca Peliti
2012-12-17T23:59:59.000Z
We derive the equations governing the protocols minimizing the heat released by a continuous-time Markov jump process on a one-dimensional countable state space during a transition between assigned initial and final probability distributions in a finite time horizon. In particular, we identify the hypotheses on the transition rates under which the optimal control strategy and the probability distribution of the Markov jump problem obey a system of differential equations of Hamilton-Bellman-Jacobi-type. As the state-space mesh tends to zero, these equations converge to those satisfied by the diffusion process minimizing the heat released in the Langevin formulation of the same problem. We also show that in full analogy with the continuum case, heat minimization is equivalent to entropy production minimization. Thus, our results may be interpreted as a refined version of the second law of thermodynamics.
Hydrodynamic force characteristics in the splash zone
Daliri, M.R.; Haritos, N. [Univ. of Melbourne, Parkville, Victoria (Australia). Dept. of Civil and Environmental Engineering
1996-12-31T23:59:59.000Z
A comprehensive experimental study concerned with the hydrodynamic force characteristics of both rigid and compliant surface piercing cylinders, with a major focus on the local nature of these characteristics as realized in the splash zone and in the fully submerged zone immediately below this region, has been in progress at the University of Melbourne for the last three years. This paper concentrates on a portion of this study associated with uni-directional regular wave inputs with wave steepness (H/{lambda}) in the range 0.0005--0.1580 and Keulegan-Carpenter (KC) numbers in the range 2--15 which encompasses inertia force dominant (KC<5) to drag force significant conditions (5
The University of New Mexico An NSF Integrative Graduate
New Mexico, University of
The University of New Mexico An NSF Integrative Graduate Education and Research Traineeship the mesoscale hydrodynamic, lubrication, and depletion forces. In a recent paper, featured on the cover
Jumping-Droplet-Enhanced Condensation on Scalable Superhydrophobic Nanostructured Surfaces
Miljkovic, N; Enright, R; Nam, Y; Lopez, K; Dou, N; Sack, J; Wang, E
2012-01-01T23:59:59.000Z
When droplets coalesce on a superhydrophobic nanostructured surface, the resulting droplet can jump from the surface due to the release of excess surface energy. If designed properly, these superhydrophobic nanostructured surfaces can not only allow for easy droplet removal at micrometric length scales during condensation but also promise to enhance heat transfer performance. However, the rationale for the design of an ideal nanostructured surface as well as heat transfer experiments demonstrating the advantage of this jumping behavior are lacking. Here, we show that silanized copper oxide surfaces created via a simple fabrication method can achieve highly efficient jumping-droplet condensation heat transfer. We experimentally demonstrated a 25% higher overall heat flux and 30% higher condensation heat transfer coefficient compared to state-of-the-art hydrophobic condensing surfaces at low supersaturations (<1.12). This work not only shows significant condensation heat transfer enhancement but also promises a low cost and scalable approach to increase efficiency for applications such as atmospheric water harvesting and dehumidification. Furthermore, the results offer insights and an avenue to achieve high flux superhydrophobic condensation.
Self-consistent solution of cosmological radiation-hydrodynamics and chemical ionization
Reynolds, Daniel R. [Mathematics, Southern Methodist University, Dallas, TX 75275-0156 (United States)], E-mail: reynolds@smu.edu; Hayes, John C. [Lawrence Livermore National Lab, P.O. Box 808, L-551, Livermore, CA 94551 (United States)], E-mail: jchayes@llnl.gov; Paschos, Pascal [Ctr. for Astrophysics and Space Sciences, U.C. San Diego, La Jolla, CA 92093 (United States)], E-mail: ppaschos@minbari.ucsd.edu; Norman, Michael L. [Ctr. for Astrophysics and Space Sciences, U.C. San Diego, La Jolla, CA 92093 (United States); Physics Department, U.C. San Diego, La Jolla, CA 92093 (United States)], E-mail: mlnorman@ucsd.edu
2009-10-01T23:59:59.000Z
We consider a PDE system comprising compressible hydrodynamics, flux-limited diffusion radiation transport and chemical ionization kinetics in a cosmologically-expanding universe. Under an operator-split framework, the cosmological hydrodynamics equations are solved through the piecewise parabolic method, as implemented in the Enzo community hydrodynamics code. The remainder of the model, including radiation transport, chemical ionization kinetics, and gas energy feedback, form a stiff coupled PDE system, which we solve using a fully-implicit inexact Newton approach, and which forms the crux of this paper. The inner linear Newton systems are solved using a Schur complement formulation, and employ a multigrid-preconditioned conjugate gradient solver for the inner Schur systems. We describe this approach and provide results on a suite of test problems, demonstrating its accuracy, robustness, and scalability to very large problems.
Jump Steady Resort Space Heating Low Temperature Geothermal Facility | Open
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are8COaBulkTransmissionSitingProcess.pdfGetecGtelInteriasIowa: Energy Resources JumpJudson, SouthJumao Photonics Co
Hydrodynamic simulations of self-phoretic microswimmers
Mingcheng Yang; Adam Wysocki; Marisol Ripoll
2014-03-04T23:59:59.000Z
A mesoscopic hydrodynamic model to simulate synthetic self-propelled Janus particles which is thermophoretically or diffusiophoretically driven is here developed. We first propose a model for a passive colloidal sphere which reproduces the correct rotational dynamics together with strong phoretic effect. This colloid solution model employs a multiparticle collision dynamics description of the solvent, and combines potential interactions with the solvent, with stick boundary conditions. Asymmetric and specific colloidal surface is introduced to produce the properties of self-phoretic Janus particles. A comparative study of Janus and microdimer phoretic swimmers is performed in terms of their swimming velocities and induced flow behavior. Self-phoretic microdimers display long range hydrodynamic interactions and can be characterized as pullers or pushers. In contrast, Janus particles are characterized by short range hydrodynamic interactions and behave as neutral swimmers. Our model nicely mimics those recent experimental realization of the self-phoretic Janus particles.
Ionizing Radiation in Smoothed Particle Hydrodynamics
O. Kessel-Deynet; A. Burkert
2000-02-11T23:59:59.000Z
A new method for the inclusion of ionizing radiation from uniform radiation fields into 3D Smoothed Particle Hydrodynamics (SPHI) simulations is presented. We calculate the optical depth for the Lyman continuum radiation from the source towards the SPHI particles by ray-tracing integration. The time-dependent ionization rate equation is then solved locally for the particles within the ionizing radiation field. Using test calculations, we explore the numerical behaviour of the code with respect to the implementation of the time-dependent ionization rate equation. We also test the coupling of the heating caused by the ionization to the hydrodynamical part of the SPHI code.
Bounce-free spherical hydrodynamic implosion
Kagan, Grigory; Tang Xianzhu; Hsu, Scott C.; Awe, Thomas J. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
2011-12-15T23:59:59.000Z
In a bounce-free spherical hydrodynamic implosion, the post-stagnation hot core plasma does not expand against the imploding flow. Such an implosion scheme has the advantage of improving the dwell time of the burning fuel, resulting in a higher fusion burn-up fraction. The existence of bounce-free spherical implosions is demonstrated by explicitly constructing a family of self-similar solutions to the spherically symmetric ideal hydrodynamic equations. When applied to a specific example of plasma liner driven magneto-inertial fusion, the bounce-free solution is found to produce at least a factor of four improvement in dwell time and fusion energy gain.
Dissipative hydrodynamics in 2+1 dimensions
A. K. Chaudhuri
2007-03-12T23:59:59.000Z
In a first order theory of dissipative hydrodynamics, we have simulated hydrodynamic evolution of QGP fluid with dissipation due to shear viscosity only. Simulation confirms that compared to an ideal fluid, energy density or temperature of a viscous fluid evolve slowly. Transverse expansion is also more in viscous fluid. We also study the effect of viscosity on particle production. Particle production is enhanced, more at large $p_T$. The elliptic flow on the otherhand decreases and shows a tendency to saturate at large $p_T$.
Parity Breaking Transport in Lifshitz Hydrodynamics
Carlos Hoyos; Adiel Meyer; Yaron Oz
2015-05-12T23:59:59.000Z
We derive the constitutive relations of first order charged hydrodynamics for theories with Lifshitz scaling and broken parity in $2+1$ and $3+1$ spacetime dimensions. In addition to the anomalous (in $3+1$) or Hall (in $2+1$) transport of relativistic hydrodynamics, there is an additional non-dissipative transport allowed by the absence of boost invariance. We analyze the non-relativistic limit and use a phenomenological model of a strange metal to argue that these effects can be measured in principle by using electromagnetic fields with non-zero gradients.
NOAA Fisheries Protocols For Hydro-dynamic Dredge Surveys
NOAA Fisheries Protocols For Hydro-dynamic Dredge Surveys: Surf Clams and Ocean Quahogs December 19..................................................................................................................................... 1 NOAA Fisheries Hydro-dynamic Clam Dredge Survey Protocols........................................................................... 5 Clam Dredge Construction and Repair
Optimal Linear Quadratic Regulator for Markovian Jump Linear Systems, in the
Baras, John S.
, in the last fifteen, the classical paradigms of optimal control for Markovian jump linear systems (see CostaOptimal Linear Quadratic Regulator for Markovian Jump Linear Systems, in the presence of one time] and in the design of controllers Chizeck [1986] of controllers for Markovian jump linear systems. More specifically
Vapor chambers with jumping-drop liquid return from superhydrophobic condensers
Chen, Chuan-Hua
Vapor chambers with jumping-drop liquid return from superhydrophobic condensers Jonathan B. Boreyko January 2013 Accepted 28 January 2013 Keywords: Jumping drops Vapor chamber Superhydrophobicity Wick-propelled jumping drops on a superhydrophobic condenser offer a new mechanism to return the working fluid
Stabilizing geometry for hydrodynamic rotary seals
Dietle, Lannie L. (Houston, TX); Schroeder, John E. (Richmond, TX)
2010-08-10T23:59:59.000Z
A hydrodynamic sealing assembly including a first component having first and second walls and a peripheral wall defining a seal groove, a second component having a rotatable surface relative to said first component, and a hydrodynamic seal comprising a seal body of generally ring-shaped configuration having a circumference. The seal body includes hydrodynamic and static sealing lips each having a cross-sectional area that substantially vary in time with each other about the circumference. In an uninstalled condition, the seal body has a length defined between first and second seal body ends which varies in time with the hydrodynamic sealing lip cross-sectional area. The first and second ends generally face the first and second walls, respectively. In the uninstalled condition, the first end is angulated relative to the first wall and the second end is angulated relative to the second wall. The seal body has a twist-limiting surface adjacent the static sealing lip. In the uninstalled condition, the twist-limiting surface is angulated relative to the peripheral wall and varies along the circumference. A seal body discontinuity and a first component discontinuity mate to prevent rotation of the seal body relative to the first component.
General Relativity as Geometro-Hydrodynamics
B. L. Hu
1996-07-29T23:59:59.000Z
In the spirit of Sakharov's `metric elasticity' proposal, we draw a loose analogy between general relativity and the hydrodynamic state of a quantum gas. In the `top-down' approach, we examine the various conditions which underlie the transition from some candidate theory of quantum gravity to general relativity. Our emphasis here is more on the `bottom-up' approach, where one starts with the semiclassical theory of gravity and examines how it is modified by graviton and quantum field excitations near and above the Planck scale. We mention three aspects based on our recent findings: 1) Emergence of stochastic behavior of spacetime and matter fields depicted by an Einstein-Langevin equation. The backreaction of quantum fields on the classical background spacetime manifests as a fluctuation-dissipation relation. 2) Manifestation of stochastic behavior in effective theories below the threshold arising from excitations above. The implication for general relativity is that such Planckian effects, though exponentially suppressed, is in principle detectable at sub-Planckian energies. 3) Decoherence of correlation histories and quantum to classical transition. From Gell-Mann and Hartle's observation that the hydrodynamic variables which obey conservation laws are most readily decohered, one can, in the spirit of Wheeler, view the conserved Bianchi identity obeyed by the Einstein tensor as an indication that general relativity is a hydrodynamic theory of geometry. Many outstanding issues surrounding the transition to general relativity are of a nature similar to hydrodynamics and mesoscopic physics.
Simple Waves in Ideal Radiation Hydrodynamics
Bryan M. Johnson
2008-11-24T23:59:59.000Z
In the dynamic diffusion limit of radiation hydrodynamics, advection dominates diffusion; the latter primarily affects small scales and has negligible impact on the large scale flow. The radiation can thus be accurately regarded as an ideal fluid, i.e., radiative diffusion can be neglected along with other forms of dissipation. This viewpoint is applied here to an analysis of simple waves in an ideal radiating fluid. It is shown that much of the hydrodynamic analysis carries over by simply replacing the material sound speed, pressure and index with the values appropriate for a radiating fluid. A complete analysis is performed for a centered rarefaction wave, and expressions are provided for the Riemann invariants and characteristic curves of the one-dimensional system of equations. The analytical solution is checked for consistency against a finite difference numerical integration, and the validity of neglecting the diffusion operator is demonstrated. An interesting physical result is that for a material component with a large number of internal degrees of freedom and an internal energy greater than that of the radiation, the sound speed increases as the fluid is rarefied. These solutions are an excellent test for radiation hydrodynamic codes operating in the dynamic diffusion regime. The general approach may be useful in the development of Godunov numerical schemes for radiation hydrodynamics.
Compressible fluid model for hydrodynamic lubrication cavitation
Sart, Remi
Compressible fluid model for hydrodynamic lubrication cavitation G. Bayada L. Chupin I.C.J. UMR.chupin@math.univ-bpclermont.fr Keywords: cavitation, compressible Reynolds equation Date: april 2013 Summary In this paper, it is shown how vaporous cavitation in lubricant films can be modelled in a physically justified manner through
Massachusetts Institute of Technology Hydrodynamics | Open Energy
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov YouKizildere I Geothermal Pwer Plant JumpMarysville, Ohio: Energy Resources Jump to:Michigan: Energy
Precautionary Measures for Credit Risk Management in Jump Models
Egami, Masahiko
2011-01-01T23:59:59.000Z
Sustaining efficiency and stability by properly controlling the equity to asset ratio is one of the most important and difficult challenges in bank management. Due to unexpected and abrupt decline of asset values, a bank must closely monitor its net worth as well as market conditions, and one of its important concerns is when to raise more capital so as not to violate capital adequacy requirements. In this paper, we model the tradeoff between avoiding costs of delay and premature capital raising, and solve the corresponding optimal stopping problem. In order to model defaults in a bank's loan/credit business portfolios, we represent its net worth by Levy processes, and solve explicitly for the double exponential jump diffusion process and for a general spectrally negative Levy process.
Markov Jump Processes Approximating a Non-Symmetric Generalized Diffusion
Limic, Nedzad, E-mail: nlimic@math.hr [University of Zagreb, Dept. of Mathematics (Croatia)
2011-08-15T23:59:59.000Z
Consider a non-symmetric generalized diffusion X( Dot-Operator ) in Double-Struck-Capital-R {sup d} determined by the differential operator A(x) = -{Sigma}{sub ij} {partial_derivative}{sub i}a{sub ij}(x){partial_derivative}{sub j} + {Sigma}{sub i} b{sub i}(x){partial_derivative}{sub i}. In this paper the diffusion process is approximated by Markov jump processes X{sub n}( Dot-Operator ), in homogeneous and isotropic grids G{sub n} Subset-Of Double-Struck-Capital-R {sup d}, which converge in distribution in the Skorokhod space D([0,{infinity}), Double-Struck-Capital-R {sup d}) to the diffusion X( Dot-Operator ). The generators of X{sub n}( Dot-Operator ) are constructed explicitly. Due to the homogeneity and isotropy of grids, the proposed method for d{>=}3 can be applied to processes for which the diffusion tensor {l_brace}a{sub ij}(x){r_brace}{sub 11}{sup dd} fulfills an additional condition. The proposed construction offers a simple method for simulation of sample paths of non-symmetric generalized diffusion. Simulations are carried out in terms of jump processes X{sub n}( Dot-Operator ). For piece-wise constant functions a{sub ij} on Double-Struck-Capital-R {sup d} and piece-wise continuous functions a{sub ij} on Double-Struck-Capital-R {sup 2} the construction and principal algorithm are described enabling an easy implementation into a computer code.
MHK Technologies/Oregon State University Columbia Power Technologies...
Jump to: navigation, search << Return to the MHK database homepage Oregon State University Columbia Power Technologies Direct Drive Point Absorber.jpg Technology Profile...
China Solar Energy Ltd Tianpu Xianxing Group aka Beijing Universal...
China Solar Energy Ltd Tianpu Xianxing Group aka Beijing Universal Antecedence Jump to: navigation, search Name: China Solar Energy Ltd (Tianpu Xianxing Group, aka Beijing...
Pursuit and Synchronization in Hydrodynamic Dipoles
Kanso, Eva
2015-01-01T23:59:59.000Z
We study theoretically the behavior of a class of hydrodynamic dipoles. This study is motivated by recent experiments on synthetic and biological swimmers in microfluidic \\textit{Hele-Shaw} type geometries. Under such confinement, a swimmer's hydrodynamic signature is that of a potential source dipole, and the long-range interactions among swimmers are obtained from the superposition of dipole singularities. Here, we recall the equations governing the positions and orientations of interacting asymmetric swimmers in doubly-periodic domains, and focus on the dynamics of swimmer pairs. We obtain two families of `relative equilibria'-type solutions that correspond to pursuit and synchronization of the two swimmers, respectively. Interestingly, the pursuit mode is stable for large tail swimmers whereas the synchronization mode is stable for large head swimmers. These results have profound implications on the collective behavior reported in several recent studies on populations of confined microswimmers.
Hu, Huosheng
fish Robotic design SimulationObjectives Hydrodynamic testsThe main objective of the SHOAL project is to design and develop three The hydrodynamic component will simulate fish ICT call: Project contract number in this consortium, the University of ESSEX has successfully built the advanced robotic fish (shown in the left
Jumping into buckets, or How to decontaminate overlapping fat jets
Koichi Hamaguchi; Seng Pei Liew; Martin Stoll
2015-05-12T23:59:59.000Z
At the LHC, tagging boosted heavy particle resonances which decay hadronically, such as top quarks and Higgs bosons, can play an essential role in new physics searches. In events with high multiplicity, however, the standard approach to tag boosted resonances by a large-radius fat jet becomes difficult because the resonances are not well-separated from other hard radiation. In this paper, we propose a different approach to tag and reconstruct boosted resonances by using the recently proposed mass-jump jet algorithm. A key feature of the algorithm is the flexible radius of the jets, which results from a terminating veto that prevents the recombination of two hard prongs if their combined jet mass is substantially larger than the masses of the separate prongs. The idea of collecting jets in "buckets" is also used. As an example, we consider the fully hadronic final state of pair-produced vectorlike top partners at the LHC, $pp\\to T\\bar{T}\\to t\\bar{t}HH$, and show that the new approach works better than the corresponding generalized $k_T$ jet clustering algorithm. We also show that tagging and kinematic reconstruction of boosted top quarks and Higgs bosons are possible with good quality even in these very busy final states. The vectorlike top partners are kinematically reconstructed, which allows their direct mass measurement.
Jumping into buckets, or How to decontaminate overlapping fat jets
Hamaguchi, Koichi; Stoll, Martin
2015-01-01T23:59:59.000Z
At the LHC, tagging boosted heavy particle resonances which decay hadronically, such as top quarks and Higgs bosons, can play an essential role in new physics searches. In events with high multiplicity, however, the standard approach to tag boosted resonances by a large-radius fat jet becomes difficult because the resonances are not well-separated from other hard radiation. In this paper, we propose a different approach to tag and reconstruct boosted resonances by using the recently proposed mass-jump jet algorithm. A key feature of the algorithm is the flexible radius of the jets, which results from a terminating veto that prevents the recombination of two hard prongs if their combined jet mass is substantially larger than the masses of the separate prongs. The idea of collecting jets in "buckets" is also used. As an example, we consider the fully hadronic final state of pair-produced vectorlike top partners at the LHC, $pp\\to T\\bar{T}\\to t\\bar{t}HH$, and show that the new approach works better than the corr...
Hydrodynamic forces due to waves and a current induced on a pipeline placed in an open trench
Lee, Jaeyoung
1991-01-01T23:59:59.000Z
HYDRODYNAMIC FORCES DUE TO WAVES AND A CURRENT INDUCED ON A PIPELINE PLACED IN AN OPEN TRENCH A Thesis by JAEYOUNG LEE Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements... for the degree of MASTER OF SCIENCE December 1991 Major Subject: Ocean Engineering HYDRODYNAMIC FORCES DUE TO WAVES AND A CURRENT INDUCED ON A PIPELINE PLACED IN AN OPEN TRENCH A Thesis by JAEYOUNG LEE Approved as to style and content by: John B...
Basset, Yves
Journal of Natural History, 2000, 34, 57155 The jumping plant-lice (Hemiptera, Psylloidea: Anacardiaceae, biogeography, cladistics, discriminant analysis, Hemiptera, host plant relationships, phylogeny
Consistent description of kinetics and hydrodynamics of dusty plasma
Markiv, B. [Institute for Condensed Matter Physics of the National Academy of Sciences of Ukraine, 1 Svientsitskii St., 79011 Lviv (Ukraine)] [Institute for Condensed Matter Physics of the National Academy of Sciences of Ukraine, 1 Svientsitskii St., 79011 Lviv (Ukraine); Tokarchuk, M. [Institute for Condensed Matter Physics of the National Academy of Sciences of Ukraine, 1 Svientsitskii St., 79011 Lviv (Ukraine) [Institute for Condensed Matter Physics of the National Academy of Sciences of Ukraine, 1 Svientsitskii St., 79011 Lviv (Ukraine); National University “Lviv Polytechnic,” 12 Bandera St., 79013 Lviv (Ukraine)
2014-02-15T23:59:59.000Z
A consistent statistical description of kinetics and hydrodynamics of dusty plasma is proposed based on the Zubarev nonequilibrium statistical operator method. For the case of partial dynamics, the nonequilibrium statistical operator and the generalized transport equations for a consistent description of kinetics of dust particles and hydrodynamics of electrons, ions, and neutral atoms are obtained. In the approximation of weakly nonequilibrium process, a spectrum of collective excitations of dusty plasma is investigated in the hydrodynamic limit.
Smoothed Particle Hydrodynamics pore-scale simulations of unstable...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
experiments using the Pair-Wise Force Smoothed Particle Hydrodynamics (PF-SPH) multiphase flow model. First, we derived analytical expressions relating parameters in the...
axis radiographic hydrodynamic: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
For an "empty vacuum" the hydrodynamic equations are familiar ones (shallow water-wave equations) and they describe an experimentally observed phenomenon -- the...
Particle-Based Mesoscale Hydrodynamic Techniques
Hiroshi Noguchi; Norio Kikuchi; Gerhard Gompper
2006-10-31T23:59:59.000Z
Dissipative particle dynamics (DPD) and multi-particle collision (MPC) dynamics are powerful tools to study mesoscale hydrodynamic phenomena accompanied by thermal fluctuations. To understand the advantages of these types of mesoscale simulation techniques in more detail, we propose new two methods, which are intermediate between DPD and MPC -- DPD with a multibody thermostat (DPD-MT), and MPC-Langevin dynamics (MPC-LD). The key features are applying a Langevin thermostat to the relative velocities of pairs of particles or multi-particle collisions, and whether or not to employ collision cells. The viscosity of MPC-LD is derived analytically, in very good agreement with the results of numerical simulations.
Asymptotic equivalence of jumps Lvy processes and their discrete counterpart Pierre tora
Paris-Sud XI, Université de
Asymptotic equivalence of jumps Lévy processes and their discrete counterpart Pierre Étoréa , Sana.Mariucci@imag.fr Abstract We establish the global asymptotic equivalence between a pure jumps Lévy process {Xt} on the time Poisson independent random variables with parameters linked with the Lévy measure . The equivalence result
Wolfe, Patrick J.
Impact of jumps on returns and realised variances: econometric analysis of time-deformed L In order to assess the effect of jumps on realised variance calculations, we study some of the econometric econometric work on realised variance. Keywords: Kalman filter, L´evy process, Long-memory, Quasi
Internal geophysics (Physics of Earth's interior) Jump conditions and dynamic surface tension of momentum across the interface, a possibly anisotropic surface tension and terms including an inter- face equals the jump of pressure; and in the presence of surface tension defined as a capillary action due
Sandia National Laboratories Hydrodynamics | Open Energy Information
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Hydrodynamic Testing Facilities Database | Open Energy Information
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are8COaBulkTransmissionSitingProcess.pdfGetecGtel JumpCounty, Texas: EnergyHy9 CorporationHydra FuelLtdFacilities
Hydrodynamic Tesla Wheel Flume for Model and Prototype Testing
Wood, Stephen L.
The Tesla turbine, U.S. Patent 1,061,206 -- May 6, 1913 was invented by Nikola Tesla as a means to extractHydrodynamic Tesla Wheel Flume for Model and Prototype Testing Spencer Jenkins, Chris Scott, Jacob Engineering department at Florida Institute of Technology (Florida Tech) has developed a Hydrodynamic Tesla
TRANSONIC HYDRODYNAMIC ESCAPE OF HYDROGEN FROM EXTRASOLAR PLANETARY ATMOSPHERES
De Sterck, Hans
. The model uses a two-dimensional energy depo- sition calculation instead of the single-layer heating planets is investigated using the model. The importance of hydrogen hydrodynamic escape for the longTRANSONIC HYDRODYNAMIC ESCAPE OF HYDROGEN FROM EXTRASOLAR PLANETARY ATMOSPHERES Feng Tian,1, 2 Owen
Hu, Chia-Ren.
1992-01-01T23:59:59.000Z
superfluid sandwiched between two parallel boundaries that are boosted adiabatically from rest to a finite velocity, and (ii) a two-dimensional two-component Coulomb gas (considered as a set of parallel line charges in three dimensions), sandwiched between...
Green's functions and hydrodynamics for isotopic binary diffusion
R. van Zon; E. G. D. Cohen
2005-08-10T23:59:59.000Z
We study classical binary fluid mixtures in which densities vary on very short time (ps) and length (nm) scales, such that hydrodynamics does not apply. In a pure fluid with a localized heat pulse the breakdown of hydrodynamics was overcome using Green's functions which connect the initial densities to those at later times. Numerically it appeared that for long times the results from the Green's functions would approach hydrodynamics. In this paper we extend the Green's functions theory to binary mixtures. For the case of isothermal isobaric mutual diffusion in isotopic binary mixtures and ideal binary mixtures, which is easier to handle than heat conduction yet still non-trivial, we show analytically that in the Green's function approach one recovers hydrodynamic behaviour at long time scales provided the system reaches local equilibrium at long times. This is a first step toward giving the Green's function theory a firmer basis because it can for this case be considered as an extension of hydrodynamics.
On the hydrodynamics of the matter reinserted within superstellar clusters
Tenorio-Tagle, G; Palous, S S J; Tenorio-Tagle, Guillermo; Wunsch, Richard; Palous, Sergiy Silich & Jan
2006-01-01T23:59:59.000Z
We present semi-analytical and numerical models, accounting for the impact of radiative cooling on the hydrodynamics of the matter reinserted as strong stellar winds and supernovae within the volume occupied by young, massive and compact superstellar clusters. First of all we corroborate the location of the threshold line in the mechanical energy input rate vs the cluster size plane, found by Silich et al. (2004). Such a line separates clusters able to drive a quasi-adiabatic or a strongly radiative wind from clusters in which catastrophic cooling occurs within the star cluster volume. Then we show that the latter, clusters above the threshold line, undergo a bimodal behavior in which the central densest zones cool rapidly and accumulate the injected matter to eventually feed further generations of star formation, while the outer zones are still able to drive a stationary wind. The results are presented into a series of universal dimensionless diagrams from which one can infer: the size of the two zones, the ...
Radiation Hydrodynamical Evolution of Primordial H II Regions
Daniel Whalen; Tom Abel; Michael L. Norman
2004-03-02T23:59:59.000Z
We simulate the ionization environment of z ~ 20 luminous objects formed within the framework of the current CDM cosmology and compute their UV escape fraction. These objects are likely single very massive stars that are copious UV emitters. We present analytical estimates as well as one--dimensional radiation hydrodynamical calculations of the evolution of these first HII regions in the universe. The initially D--type ionization front evolves to become R--type within $\\lesssim 10^5$ yrs at a distance $\\sim1$ pc. This ionization front then completely overruns the halo, accelerating an expanding shell of gas outward to velocities in excess of 30 km s$^{-1}$, about ten times the escape velocity of the confining dark matter halo. We find that the evolution of the HII region depends only weakly on the assumed stellar ionizing luminosities. Consequently, most of the gas surrounding the first stars will leave the dark halo whether or not the stars produce supernovae. If they form the first massive seed black holes these are unlikely to accrete within a Hubble time after they formed until they are incorporated into larger dark matter halos that contain more gas. Because these I--fronts exit the halo on timescales much shorter than the stars' main sequence lifetimes their host halos have UV escape fractions of $\\gtrsim 0.95$, fixing an important parameter for theoretical studies of cosmological hydrogen reionization.
Code Differentiation for Hydrodynamic Model Optimization
Henninger, R.J.; Maudlin, P.J.
1999-06-27T23:59:59.000Z
Use of a hydrodynamics code for experimental data fitting purposes (an optimization problem) requires information about how a computed result changes when the model parameters change. These so-called sensitivities provide the gradient that determines the search direction for modifying the parameters to find an optimal result. Here, the authors apply code-based automatic differentiation (AD) techniques applied in the forward and adjoint modes to two problems with 12 parameters to obtain these gradients and compare the computational efficiency and accuracy of the various methods. They fit the pressure trace from a one-dimensional flyer-plate experiment and examine the accuracy for a two-dimensional jet-formation problem. For the flyer-plate experiment, the adjoint mode requires similar or less computer time than the forward methods. Additional parameters will not change the adjoint mode run time appreciably, which is a distinct advantage for this method. Obtaining ''accurate'' sensitivities for the j et problem parameters remains problematic.
An Owner's Guide to Smoothed Particle Hydrodynamics
T. J. Martin; F. R. Pearce; P. A. Thomas
1993-10-13T23:59:59.000Z
We present a practical guide to Smoothed Particle Hydrodynamics (\\SPH) and its application to astrophysical problems. Although remarkably robust, \\SPH\\ must be used with care if the results are to be meaningful since the accuracy of \\SPH\\ is sensitive to the arrangement of the particles and the form of the smoothing kernel. In particular, the initial conditions for any \\SPH\\ simulation must consist of particles in dynamic equilibrium. We describe some of the numerical difficulties that may be encountered when using \\SPH, and how these may be overcome. Through our experience in using \\SPH\\ code to model convective stars, galaxy clusters and large scale structure problems we have developed many diagnostic tests. We give these here as an aid to rapid identification of errors, together with a list of basic prerequisites for the most efficient implementation of \\SPH.
Flow stabilization with active hydrodynamic cloaks
Urzhumov, Yaroslav A; 10.1103/PhysRevE.86.056313
2012-01-01T23:59:59.000Z
We demonstrate that fluid flow cloaking solutions based on active hydrodynamic metamaterials exist for two-dimensional flows past a cylinder in a wide range of Reynolds numbers, up to approximately 200. Within the framework of the classical Brinkman equation for homogenized porous flow, we demonstrate using two different methods that such cloaked flows can be dynamically stable for $Re$ in the range 5-119. The first, highly efficient, method is based on a linearization of the Brinkman-Navier-Stokes equation and finding the eigenfrequencies of the least stable eigen-perturbations; the second method is a direct, numerical integration in the time domain. We show that, by suppressing the Karman vortex street in the weekly turbulent wake, porous flow cloaks can raise the critical Reynolds number up to about 120, or five times greater than for a bare, uncloaked cylinder.
Non-linear hydrodynamics of axion dark matter: relative velocity effects and "quantum forces"
Marsh, David J E
2015-01-01T23:59:59.000Z
The non-linear hydrodynamic equations for axion/scalar field dark matter (DM) in the non-relativistic Madelung-Shcr\\"{o}dinger form are derived in a simple manner, including the effects of universal expansion and Hubble drag. The hydrodynamic equations are used to investigate the relative velocity between axion DM and baryons, and the moving-background perturbation theory (MBPT) derived. Axions massive enough to be all of the DM do not affect the coherence length of the relative velocity, but the MBPT equations are modified by the inclusion of the axion effective sound speed. These MBPT equations are necessary for accurately modelling the effects of axion DM on the formation of the first cosmic structures, and suggest that the 21cm power spectrum could improve constraints on axion mass by up to four orders of magnitude with respect to the current best constraints. A further application of these results uses the "quantum force" analogy to model scalar field gradient energy in a smoothed-particle hydrodynamics ...
Jiang, George J.
In this paper, we identify jumps in U.S. Treasury-bond (T-bond) prices and investigate what causes such unexpected large price changes. In particular, we examine the relative importance of macroeconomic news announcements ...
Rochefort, Alain
Effects of long jumps, reversible aggregation, and Meyer-Neldel rule on submonolayer epitaxial with an embedded-atom-method molecular-dynamics study that the compensation law or the Meyer-Neldel rule MNR could
Boyer, Edmond
Bow-wave-like hydraulic jump and horseshoe vortex around an obstacle in a supercritical open the obstacle, two main flow structures are observed: i a hydraulic jump in the near-surface region and ii turbulent regime , the detachment length of the hydraulic jump exceeds the one of the horseshoe vortex
Effect of shockwave-induced density jump on laser plasma interactions in low-pressure ambient air
Tillack, Mark
1 Effect of shockwave-induced density jump on laser plasma interactions in low-pressure ambient air jump were investigated in low- pressure ambient air during the laser pulse using an optical interferometer. A tiny shockwave-induced density jump could be observed clearly in ambient air with pressure
Brandeis University Brown University
Jiang, Huiqiang
Institute of Technology McGill University Michigan State University New York University Northwestern University of Kansas University of Maryland, College Park University of Michigan University of MinnesotaBrandeis University Brown University California Institute of Technology Carnegie Mellon University
Second-Order Accurate Method for Solving Radiation-Hydrodynamics
Edwards, Jarrod Douglas
2013-11-12T23:59:59.000Z
Second-order discretization for radiation-hydrodynamics is currently an area of great interest. Second-order methods used to solve the respective single-physics problems often differ fundamentally, making it difficult to combine them in a second...
Characterizing Flow in Oil Reservoir Rock Using Smooth Particle Hydrodynamics
Holmes, David W.
In this paper, a 3D Smooth Particle Hydrodynamics (SPH) simulator for modeling grain scale fluid flow in porous rock is presented. The versatility of the SPH method has driven its use in increasingly complex areas of flow ...
A GPU Accelerated Smoothed Particle Hydrodynamics Capability For Houdini
Sanford, Mathew
2012-10-19T23:59:59.000Z
on the desired result. One common fluid simulation technique is the Smoothed Particle Hydrodynamics (SPH) method. This method is highly parellelizable. I have implemented a method to integrate a Graphics Processor Unit (GPU) accelerated SPH capability into the 3D...
EIS-0228: Dual Axis Radiographic Hydrodynamic Test (DARHT) Facility
Broader source: Energy.gov [DOE]
This EIS evaluates the potential environmental impact of a proposal to construct and operate the Dual Axis Radiographic Hydrodynamic Test (DARHT) facility at Los Alamos National Laboratory (LANL)...
The hydrodynamics of water-walking insects and spiders
Hu, David L., 1979-
2006-01-01T23:59:59.000Z
We present a combined experimental and theoretical investigation of the numerous hydrodynamic propulsion mechanisms employed by water-walking arthropods (insects and spiders). In our experimental study, high speed ...
Bulk viscosity and cavitation in boost-invariant hydrodynamic expansion
Rajagopal, Krishna
We solve second order relativistic hydrodynamics equations for a boost-invariant 1+1-dimensional expanding fluid with an equation of state taken from lattice calculations of the thermodynamics of strongly coupled quark-gluon ...
Hydrodynamics and sediment transport in natural and beneficial use marshes
Kushwaha, Vaishali
2006-10-30T23:59:59.000Z
or siltation. The research reported here applies an engineering approach to analysis of tidal creeks in natural and beneficial use marshes of Galveston Bay. The hydrodynamic numerical model, DYNLET, was used to assess circulation in marsh channels. A...
Photoevaporation of protoplanetary discs I: hydrodynamic models
R. D. Alexander; C. J. Clarke; J. E. Pringle
2006-03-09T23:59:59.000Z
In this paper we consider the effect of the direct ionizing stellar radiation field on the evolution of protoplanetary discs subject to photoevaporative winds. We suggest that models which combine viscous evolution with photoevaporation of the disc (e.g. Clarke, Gendrin & Sotomayor 2001) incorrectly neglect the direct field after the inner disc has drained, at late times in the evolution. We construct models of the photoevaporative wind produced by the direct field, first using simple analytic arguments and later using detailed numerical hydrodynamics. We find that the wind produced by the direct field at late times is much larger than has previously been assumed, and we show that the mass-loss rate scales as $R_{in}^{1/2}$ (where $R_{in}$ is the radius of the instantaneous inner disc edge). We suggest that this result has important consequences for theories of disc evolution, and go on to consider the effects of this result on disc evolution in detail in a companion paper (Alexander, Clarke & Pringle 2006b).
An implicit Smooth Particle Hydrodynamic code
Charles E. Knapp
2000-04-01T23:59:59.000Z
An implicit version of the Smooth Particle Hydrodynamic (SPH) code SPHINX has been written and is working. In conjunction with the SPHINX code the new implicit code models fluids and solids under a wide range of conditions. SPH codes are Lagrangian, meshless and use particles to model the fluids and solids. The implicit code makes use of the Krylov iterative techniques for solving large linear-systems and a Newton-Raphson method for non-linear corrections. It uses numerical derivatives to construct the Jacobian matrix. It uses sparse techniques to save on memory storage and to reduce the amount of computation. It is believed that this is the first implicit SPH code to use Newton-Krylov techniques, and is also the first implicit SPH code to model solids. A description of SPH and the techniques used in the implicit code are presented. Then, the results of a number of tests cases are discussed, which include a shock tube problem, a Rayleigh-Taylor problem, a breaking dam problem, and a single jet of gas problem. The results are shown to be in very good agreement with analytic solutions, experimental results, and the explicit SPHINX code. In the case of the single jet of gas case it has been demonstrated that the implicit code can do a problem in much shorter time than the explicit code. The problem was, however, very unphysical, but it does demonstrate the potential of the implicit code. It is a first step toward a useful implicit SPH code.
Hamiltonian Hydrodynamics and Irrotational Binary Inspiral
Charalampos M. Markakis
2014-10-28T23:59:59.000Z
Gravitational waves from neutron-star and black-hole binaries carry valuable information on their physical properties and probe physics inaccessible to the laboratory. Although development of black-hole gravitational-wave templates in the past decade has been revolutionary, the corresponding work for double neutron-star systems has lagged. Neutron stars can be well-modelled as simple barotropic fluids during the part of binary inspiral most relevant to gravitational wave astronomy, but the crucial geometric and mathematical consequences of this simplification have remained computationally unexploited. In particular, Carter and Lichnerowicz have described barotropic fluid motion via classical variational principles as conformally geodesic. Moreover, Kelvin's circulation theorem implies that initially irrotational flows remain irrotational. Applied to numerical relativity, these concepts lead to novel Hamiltonian or Hamilton-Jacobi schemes for evolving relativistic fluid flows. Hamiltonian methods can conserve not only flux, but also circulation and symplecticity, and moreover do not require addition of an artificial atmosphere typically required by standard conservative methods. These properties can allow production of high-precision gravitational waveforms at low computational cost. This canonical hydrodynamics approach is applicable to a wide class of problems involving theoretical or computational fluid dynamics.
Molecular quantum wakes in the hydrodynamic plasma waveguide in air
Wu Jian; Cai Hua; Zeng Heping [State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062 (China); Milchberg, H. M. [Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742 (United States)
2010-10-15T23:59:59.000Z
We demonstrate a modulated plasma guiding effect from the molecular alignment wakes in the hydrodynamic plasma waveguide. A properly time-delayed laser pulse can be spatially confined by the hydrodynamic expansion induced plasma waveguide of an advancing femtosecond laser pulse. The spatial confinement can be further strengthened or weakened by following the quantum wakes of the impulsively excited rotational wave packets of the molecules in the plasma waveguide.
Annual Report 2006 for Hydrodynamics and Radiation Hydrodynamics with Astrophysical Applications
R. Paul Drake
2007-04-05T23:59:59.000Z
We report the ongoing work of our group in hydrodynamics and radiation hydrodynamics with astrophysical applications. During the period of the existing grant, we have carried out two types of experiments at the Omega laser. One set of experiments has studied radiatively collapsing shocks, obtaining data using a backlit pinhole with a 100 ps backlighter and beginning to develop the ability to look into the shock tube with optical or x-ray diagnostics. Other experiments have studied the deeply nonlinear development of the Rayleigh-Taylor (RT) instability from complex initial conditions, using dual-axis radiographic data with backlit pinholes and ungated detectors to complete the data set for a Ph.D. student. We lead a team that is developing a proposal for experiments at the National Ignition Facility and are involved in experiments at NIKE and LIL. All these experiments have applications to astrophysics, discussed in the corresponding papers. We assemble the targets for the experiments at Michigan, where we also prepare many of the simple components. We also have several projects underway in our laboratory involving our x-ray source. The above activities, in addition to a variety of data analysis and design projects, provide good experience for graduate and undergraduates students. In the process of doing this research we have built a research group that uses such work to train junior scientists.
Property:Hydrodynamic Testing Facility Type | Open Energy Information
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are beingZealand Jump to:Ezfeedflag Jump to: navigation,ProjectStartDate Jump to:Property EditType" Showing 25
Early hydrodynamic evolution of a stellar collision
Kushnir, Doron; Katz, Boaz [Institute for Advanced Study, Einstein Drive, Princeton, NJ 08540 (United States)
2014-04-20T23:59:59.000Z
The early phase of the hydrodynamic evolution following the collision of two stars is analyzed. Two strong shocks propagate from the contact surface and move toward the center of each star at a velocity that is a small fraction of the velocity of the approaching stars. The shocked region near the contact surface has a planar symmetry and a uniform pressure. The density vanishes at the (Lagrangian) surface of contact, and the speed of sound diverges there. The temperature, however, reaches a finite value, since as the density vanishes, the finite pressure is radiation dominated. For carbon-oxygen white dwarf (CO WD) collisions, this temperature is too low for any appreciable nuclear burning shortly after the collision, which allows for a significant fraction of the mass to be highly compressed to the density required for efficient {sup 56}Ni production in the detonation wave that follows. This property is crucial for the viability of collisions of typical CO WD as progenitors of type Ia supernovae, since otherwise only massive (>0.9 M {sub ?}) CO WDs would have led to such explosions (as required by all other progenitor models). The divergence of the speed of sound limits numerical studies of stellar collisions, as it makes convergence tests exceedingly expensive unless dedicated schemes are used. We provide a new one-dimensional Lagrangian numerical scheme to achieve this. A self-similar planar solution is derived for zero-impact parameter collisions between two identical stars, under some simplifying assumptions (including a power-law density profile), which is the planar version of previous piston problems that were studied in cylindrical and spherical symmetries.
Dissipative hydrodynamics in 2+1 dimension
A. K. Chaudhuri
2006-05-25T23:59:59.000Z
In 2+1 dimension, we have simulated the hydrodynamic evolution of QGP fluid with dissipation due to shear viscosity. Comparison of evolution of ideal and viscous fluid, both initialised under the same conditions e.g. same equilibration time, energy density and velocity profile, reveal that the dissipative fluid evolves slowly, cooling at a slower rate. Cooling get still slower for higher viscosity. The fluid velocities on the otherhand evolve faster in a dissipative fluid than in an ideal fluid. The transverse expansion is also enhanced in dissipative evolution. For the same decoupling temperature, freeze-out surface for a dissipative fluid is more extended than an ideal fluid. Dissipation produces entropy as a result of which particle production is increased. Particle production is increased due to (i) extension of the freeze-out surface and (ii) change of the equilibrium distribution function to a non-equilibrium one, the last effect being prominent at large transverse momentum. Compared to ideal fluid, transverse momentum distribution of pion production is considerably enhanced. Enhancement is more at high $p_T$ than at low $p_T$. Pion production also increases with viscosity, larger the viscosity, more is the pion production. Dissipation also modifies the elliptic flow. Elliptic flow is reduced in viscous dynamics. Also, contrary to ideal dynamics where elliptic flow continues to increase with transverse momentum, in viscous dynamics, elliptic flow tends to saturate at large transverse momentum. The analysis suggest that initial conditions of the hot, dense matter produced in Au+Au collisions at RHIC, as extracted from ideal fluid analysis can be changed significantly if the QGP fluid is viscous.
John Tatini Titantah; Mikko Karttunen
2013-03-29T23:59:59.000Z
Structure and dynamics of water remain a challenge. Resolving the properties of hydrogen bonding lies at the heart of this puzzle. Here we employ ab initio Molecular Dynamics (AIMD) simulations over a wide temperature range. The total simulation time was approx 2 ns. Both bulk water and water in the presence of a small hydrophobic molecule were simulated. We show that large-angle jumps and bond bifurcations are fundamental properties of water dynamics and that they are intimately coupled to both local density and hydrogen bond stretch oscillations in scales from about 60 to a few hundred femtoseconds: Local density differences are the driving force for bond bifurcations and the consequent large-angle jumps. The jumps are intimately connected to the recently predicted energy asymmetry. Our analysis also appears to confirm the existence of the so-called negativity track provided by the lone pairs of electrons on the oxygen atom to enable water rotation.
Large Angular Jump Mechanism Observed for Hydrogen Bond Exchange in Aqueous Perchlorate Solution
Ji, Minbiao; /SLAC, PULSE /Stanford U., Phys. Dept.; Odelius3, Michael; /Stockholm U.; Gaffney1, K.J.; /aff SLAC, PULSE
2010-06-11T23:59:59.000Z
The mechanism for hydrogen bond (H-bond) switching in solution has remained subject to debate despite extensive experimental and theoretical studies. We have applied polarization-selective multidimensional vibrational spectroscopy to investigate the H-bond exchange mechanism in aqueous NaClO{sub 4} solution. The results show that a water molecule shifts its donated H-bonds between water and perchlorate acceptors by means of large, prompt angular rotation. Using a jump-exchange kinetic model, we extract an average jump angle of 49 {+-} 4{sup o}, in qualitative agreement with the jump angle observed in molecular dynamics simulations of the same aqueous NaClO{sub 4} solution.
Engineering steady states using jump-based feedback for multipartite entanglement generation
Stevenson, R. N.; Hope, J. J.; Carvalho, A. R. R. [Department of Quantum Sciences, Research School of Physics and Engineering, Australian National University, Canberra ACT 0200 (Australia)
2011-08-15T23:59:59.000Z
We investigate the use of quantum-jump-based feedback to manipulate the stability of multipartite entangled dark states in an open quantum system. Using the model proposed in Phys. Rev. A 76, 010301(R) (2007) for a pair of atoms, we show a general strategy to produce many-body singlet stationary entangled states for larger number of atoms. In the case of four qubits, we propose a simple local feedback control that, although not optimal, is realistic and stabilizes a highly entangled state. We discuss the limitations and analyze alternative strategies within the framework of direct jump feedback schemes.
Control Improvement for Jump-Diffusion Processes with Applications to Finance
Baeuerle, Nicole, E-mail: nicole.baeuerle@kit.edu [Karlsruhe Institute of Technology, Institute for Stochastics (Germany); Rieder, Ulrich, E-mail: ulrich.rieder@uni-ulm.de [University of Ulm, Department of Optimization and Operations Research (Germany)
2012-02-15T23:59:59.000Z
We consider stochastic control problems with jump-diffusion processes and formulate an algorithm which produces, starting from a given admissible control {pi}, a new control with a better value. If no improvement is possible, then {pi} is optimal. Such an algorithm is well-known for discrete-time Markov Decision Problems under the name Howard's policy improvement algorithm. The idea can be traced back to Bellman. Here we show with the help of martingale techniques that such an algorithm can also be formulated for stochastic control problems with jump-diffusion processes. As an application we derive some interesting results in financial portfolio optimization.
Dynamics of a drop trapped inside a horizontal circular hydraulic jump
Duchesne, Alexis; Lebon, Luc; Pirat, Christophe; Limat, Laurent
2013-01-01T23:59:59.000Z
A drop of moderate size deposited inside a horizontal circular hydraulic jump of the same liquid remains trapped at the shock front and does not coalesce. In this situation the drop is moving along the jump and one observes two different motions: a periodic one (it orbitates at constant speed) and an irregular one involving reversals of the orbital motion. Modeling the drop as a rigid sphere exchanging friction with liquid across a thin film of air, we recover the orbital motion and the internal rotation of the drop. This internal rotation is experimentally observed.
Orbits and reversals of a drop rolling inside a horizontal circular hydraulic jump
Alexis Duchesne; Clément Savaro; Luc Lebon; Christophe Pirat; Laurent Limat
2013-02-14T23:59:59.000Z
We explore the complex dynamics of a non-coalescing drop of moderate size inside a circular hydraulic jump of the same liquid formed on a horizontal disk. In this situation the drop is moving along the jump and one observes two different motions: a periodic one (it orbitates at constant speed) and an irregular one involving reversals of the orbital motion. Modeling the drop as a rigid sphere exchanging friction with liquid across a thin film of air, we recover the orbital motion and the internal rotation of the drop. This internal rotation is experimentally observed.
Synchronizing a sea-level jump, final Lake Agassiz drainage, and abrupt cooling 8200 years ago
Törnqvist, Torbjörn E.
Synchronizing a sea-level jump, final Lake Agassiz drainage, and abrupt cooling 8200 years ago Yong cooling that can be directly linked to a well-documented freshwater source with a temporal resolution has received extensive interest for a wide range of reasons, including its potential role in a future
Stochastic Models of Energy Commodity Prices and Their Applications: Mean-reversion with Jumps and
California at Berkeley. University of
PWP-073 Stochastic Models of Energy Commodity Prices and Their Applications: Mean.ucei.berkeley.edu/ucei #12;Stochastic Models of Energy Commodity Prices and Their Applications: Mean-reversion with Jumps-switching and stochastic volatility into these models in order to capture the salient features of energy commodity prices
Numerical Solution of Two Asset Jump Diffusion Models for Option Valuation
Forsyth, Peter A.
Numerical Solution of Two Asset Jump Diffusion Models for Option Valuation Simon S. Clift and Peter parabolic partial integro-differential equation (PIDE). An implicit, finite difference method is derived with an FFT. The method prices both American and European style contracts indepen- dent (under some simple
Variation, jumps, market frictions and high frequency data in financial econometrics
Wolfe, Patrick J.
Variation, jumps, market frictions and high frequency data in financial econometrics Ole E the econometrics of non-parametric estimation of the components of the variation of asset prices. This very active and order books. In our view the interaction of the new data sources with new econometric methodology
Econometrics of testing for jumps in financial economics using bipower variation
Wolfe, Patrick J.
Econometrics of testing for jumps in financial economics using bipower variation Ole E. Barndorff management and asset allocation. A stream of recent papers in financial econometrics has addressed this issue of quadratic variation to the increments of the risk premium. The re- cent econometric work on this topic
Mantises exchange angular momentum between three rotating body parts to jump precisely to targets
Burrows, M.; Cullen, D. A.; Dorosenko, M.; Sutton, G. P.
2015-03-05T23:59:59.000Z
, 1406-1416. 2. Burrows, M., and Bräunig, P. (2010). Actions of motor neurons and leg muscles in jumping by planthopper insects (Hemiptera, Issidae). J. Comp. Neurol. 518, 1349-1369. 3. Burrows, M., and Sutton, G.P. (2013). Interacting gears...
Decentralized Control of Power Systems via Robust Control of Uncertain Markov Jump Parameter Systems
Pota, Himanshu Roy
are regulated by small disturbance controllers whose gains are adjusted for variations in power system model due control of small disturbances in interconnected power systems. The linearized power system dynamic modelDecentralized Control of Power Systems via Robust Control of Uncertain Markov Jump Parameter
Kinetics and Mechanisms of Sulfate Adsorption/Desorption on Goethite Using Pressure-Jump Relaxation
Sparks, Donald L.
Kinetics and Mechanisms of Sulfate Adsorption/Desorption on Goethite Using Pressure-Jump Relaxation Peng Chu Zhang* and Donald L. Sparks ABSTRACT Sulfate adsorption/desorption on goethite (Fe indicated that adsorption decreased with increased pH of the goethite suspension. The triple-layer model fit
Hoy, Ronald R.
Seismic signals are crucial for male mating success in a visual specialist jumping spider (Araneae of multicomponent seismic courtship signals in addition to and produced in concert with its multiple visual ornaments and movement displays. Here, we demonstrate the importance of these seismic signals
Self-cleaning of superhydrophobic surfaces by self-propelled jumping condensate
Chen, Chuan-Hua
Self-cleaning of superhydrophobic surfaces by self-propelled jumping condensate Katrina M. Wisdoma 2, 2013 (received for review June 24, 2012) The self-cleaning function of superhydrophobic surfaces the superhydrophobic surface is powered by the sur- face energy released upon coalescence of the condensed water phase
Jump conditions and dynamic surface tension at permeable interfaces such as the inner core boundary
Jump conditions and dynamic surface tension at permeable interfaces such as the inner core boundary as the density and viscosity changes. Independently of any intrinsic surface tension, a dynamic surface tension, a possibly anisotropic surface tension and terms including an interface mass density. In pratice
University of Pittsburgh | Open Energy Information
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University of Toledo | Open Energy Information
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West Virginia University | Open Energy Information
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From Field Theory to the Hydrodynamics of Relativistic Superfluids
Stetina, Stephan
2015-01-01T23:59:59.000Z
The hydrodynamic description of a superfluid is usually based on a two-fluid picture. In this thesis, basic properties of such a relativistic two-fluid system are derived from the underlying microscopic physics of a complex scalar quantum field theory. To obtain analytic results of all non-dissipative hydrodynamic quantities in terms of field theoretic variables, calculations are first carried out in a low-temperature and weak-coupling approximation. In a second step, the 2-particle-irreducible formalism is applied: This formalism allows for a numerical evaluation of the hydrodynamic parameters for all temperatures below the critical temperature. In addition, a system of two coupled superfluids is studied. As an application, the velocities of first and second sound in the presence of a superflow are calculated. The results show that first (second) sound evolves from a density (temperature) wave at low temperatures to a temperature (density) wave at high temperatures. This role reversal is investigated for ult...
Conformational Manipulation of DNA in Nanochannels Using Hydrodynamics
Qihao He; Hubert Ranchon; Pascal Carrivain; Yannick Viero; Joris Lacroix; Charline Blatché; Emmanuelle Daran; Jean-Marc Victor; Aurélien Bancaud
2014-09-01T23:59:59.000Z
The control over DNA elongation in nanofluidic devices holds great potential for large-scale genomic analysis. So far, the manipulation of DNA in nanochannels has been mostly carried out with electrophoresis and seldom with hydrodynamics, although the physics of soft matter in nanoscale flows has raised considerable interest over the past decade. In this report the migration of DNA is studied in nanochannels of lateral dimension spanning 100 to 500 nm using both actuation principles. We show that the relaxation kinetics are 3-fold slowed down and the extension increases up to 3-fold using hydrodynamics. We propose a model to account for the onset in elongation with the flow, which assumes that DNA response is determined by the shear-driven lift forces mediated by the proximity of the channels' walls. Overall, we suggest that hydrodynamic actuation allows for an improved manipulation of DNA in nanochannels.
Non-decaying hydrodynamic interactions along narrow channels
Misiunas, Karolis; Lauga, Eric; Lister, John R; Keyser, Ulrich F
2015-01-01T23:59:59.000Z
Particle-particle interactions are of paramount importance in every multi-body system as they determine the collective behaviour and coupling strength. Many well-known interactions like electro-static, van der Waals or screened Coulomb, decay exponentially or with negative powers of the particle spacing r. Similarly, hydrodynamic interactions between particles undergoing Brownian motion decay as 1/r in bulk, and are assumed to decay quickly in small channels. Such interactions are ubiquitous in biological and technological systems. Here we confine two particles undergoing Brownian motion in narrow, microfluidic channels and study their coupling through hydrodynamic interactions. Our experiments show that, in contrast to expectations from current theoretical understanding, the hydrodynamic particle-particle interactions are long-range and non-decaying in these channels. This new effect is of fundamental importance for the interpretation of experiments where dense mixtures of particles or molecules diffuse thro...
Bulk Viscosity Effects in Event-by-Event Relativistic Hydrodynamics
Jacquelyn Noronha-Hostler; Gabriel S. Denicol; Jorge Noronha; Rone P. G. Andrade; Frederique Grassi
2013-05-10T23:59:59.000Z
Bulk viscosity effects on the collective flow harmonics in heavy ion collisions are investigated, on an event by event basis, using a newly developed 2+1 Lagrangian hydrodynamic code named v-USPhydro which implements the Smoothed Particle Hydrodynamics (SPH) algorithm for viscous hydrodynamics. A new formula for the bulk viscous corrections present in the distribution function at freeze-out is derived starting from the Boltzmann equation for multi-hadron species. Bulk viscosity is shown to enhance the collective flow Fourier coefficients from $v_2(p_T)$ to $v_5(p_T)$ when $% p_{T}\\sim 1-3$ GeV even when the bulk viscosity to entropy density ratio, $% \\zeta/s$, is significantly smaller than $1/(4\\pi)$.
Collective excitations of hydrodynamically coupled driven colloidal particles
Harel Nagar; Yael Roichman
2014-08-21T23:59:59.000Z
Two colloidal particles, driven around an optical vortex trap, have been recently shown to pair due to an interplay between hydrodynamic interactions and the curved path they are forced to follow. We demonstrate here, that this pairing interaction can be tuned experimentally, and study its effect on the collective excitations of many particles driven around such an optical trap. We find that even though the system is overdamped, hydrodynamic interactions due to driving give rise to non-decaying excitations with characteristic dispersion relations. The collective excitations of the colloidal ring reflect fluctuations of particle pairs rather than those of single particles.
Second order hydrodynamics for a special class of gravity duals
Springer, T. [School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455 (United States)
2009-04-15T23:59:59.000Z
The sound mode hydrodynamic dispersion relation is computed up to order q{sup 3} for a class of gravitational duals which includes both Schwarzschild AdS and Dp-brane metrics. The implications for second order transport coefficients are examined within the context of Israel-Stewart theory. These sound mode results are compared with previously known results for the shear mode. This comparison allows one to determine the third order hydrodynamic contributions to the shear mode for the class of metrics considered here.
3-D HYDRODYNAMIC MODELING IN A GEOSPATIAL FRAMEWORK
Bollinger, J; Alfred Garrett, A; Larry Koffman, L; David Hayes, D
2006-08-24T23:59:59.000Z
3-D hydrodynamic models are used by the Savannah River National Laboratory (SRNL) to simulate the transport of thermal and radionuclide discharges in coastal estuary systems. Development of such models requires accurate bathymetry, coastline, and boundary condition data in conjunction with the ability to rapidly discretize model domains and interpolate the required geospatial data onto the domain. To facilitate rapid and accurate hydrodynamic model development, SRNL has developed a pre- and post-processor application in a geospatial framework to automate the creation of models using existing data. This automated capability allows development of very detailed models to maximize exploitation of available surface water radionuclide sample data and thermal imagery.
Development of a Hydrodynamic Model of Puget Sound and Northwest Straits
Yang, Zhaoqing; Khangaonkar, Tarang P.
2007-12-10T23:59:59.000Z
The hydrodynamic model used in this study is the Finite Volume Coastal Ocean Model (FVCOM) developed by the University of Massachusetts at Dartmouth. The unstructured grid and finite volume framework, as well as the capability of wetting/drying simulation and baroclinic simulation, makes FVCOM a good fit to the modeling needs for nearshore restoration in Puget Sound. The model domain covers the entire Puget Sound, Strait of Juan de Fuca, San Juan Passages, and Georgia Strait at the United States-Canada Border. The model is driven by tide, freshwater discharge, and surface wind. Preliminary model validation was conducted for tides at various locations in the straits and Puget Sound using National Oceanic and Atmospheric Administration (NOAA) tide data. The hydrodynamic model was successfully linked to the NOAA oil spill model General NOAA Operational Modeling Environment model (GNOME) to predict particle trajectories at various locations in Puget Sound. Model results demonstrated that the Puget Sound GNOME model is a useful tool to obtain first-hand information for emergency response such as oil spill and fish migration pathways.
Dong, Cheng
Hydrodynamic Shear Rate Regulates Melanoma-Leukocyte Aggregation, Melanoma Adhesion that polymorphonuclear neutrophils (PMNs) may enhance melanoma adhesion to the endothelium (EC) and subsequent microenvironment within the microcirculation. In this study, effects of hydrodynamic flow on regulating melanoma
Simon, Scott I.
Hydrodynamic Shear Rate Regulates Melanoma-Leukocyte Aggregation, Melanoma Adhesion that polymorphonuclear neutrophils (PMNs) may enhance melanoma adhesion to the endothelium (EC) and subsequent microenvironment within the microcirculation. In this study, effects of hydrodynamic flow on regulating melanoma
Compatible, energy and symmetry preserving 2D Lagrangian hydrodynamics in rz-cylindrical coordinates
Shashkov, Mikhail [Los Alamos National Laboratory; Wendroff, Burton [Los Alamos National Laboratory; Burton, Donald [Los Alamos National Laboratory; Barlow, A [AWE; Hongbin, Guo [ASU
2009-01-01T23:59:59.000Z
We present a new discretization for 2D Lagrangian hydrodynamics in rz geometry (cylindrical coordinates) that is compatible, energy conserving and symmetry preserving. We describe discretization of the basic Lagrangian hydrodynamics equations.
Epps, Brenden P
2010-01-01T23:59:59.000Z
This thesis presents an impulse framework for analyzing the hydrodynamic forces on bodies in flow. This general theoretical framework is widely applicable, and it is used to address the hydrodynamics of fish propulsion, ...
A new shock-capturing numerical scheme for ideal hydrodynamics
Zuzana Feckova; Boris Tomasik
2015-01-07T23:59:59.000Z
We present a new algorithm for solving ideal relativistic hydrodynamics based on Godunov method with an exact solution of Riemann problem for an arbitrary equation of state. Standard numerical tests are executed, such as the sound wave propagation and the shock tube problem. Low numerical viscosity and high precision are attained with proper discretization.
Onset of superradiant instabilities in the hydrodynamic vortex model
Shahar Hod
2014-07-30T23:59:59.000Z
The hydrodynamic vortex, an effective spacetime geometry for propagating sound waves, is studied analytically. In contrast with the familiar Kerr black-hole spacetime, the hydrodynamic vortex model is described by an effective acoustic geometry which has no horizons. However, this acoustic spacetime possesses an ergoregion, a property which it shares with the rotating Kerr spacetime. It has recently been shown numerically that this physical system is linearly unstable due to the superradiant scattering of sound waves in the ergoregion of the effective spacetime. In the present study we use analytical tools in order to explore the onset of these superradiant instabilities which characterize the effective spacetime geometry. In particular, we derive a simple analytical formula which describes the physical properties of the hydrodynamic vortex system in its critical (marginally-stable) state, the state which marks the boundary between stable and unstable fluid configurations. The analytically derived formula is shown to agree with the recently published numerical data for the hydrodynamic vortex system.
A new shock-capturing numerical scheme for ideal hydrodynamics
Feckova, Zuzana
2015-01-01T23:59:59.000Z
We present a new algorithm for solving ideal relativistic hydrodynamics based on Godunov method with an exact solution of Riemann problem for an arbitrary equation of state. Standard numerical tests are executed, such as the sound wave propagation and the shock tube problem. Low numerical viscosity and high precision are attained with proper discretization.
New Formulation of Causal Dissipative Hydrodynamics: Shock wave propagation
Ph. Mota; G. S. Denicol; T. Koide; T. Kodama
2007-01-19T23:59:59.000Z
The first 3D calculation of shock wave propagation in a homogeneous QGP has been performed within the new formulation of relativistic dissipative hydrodynamics which preserves the causality. We found that the relaxation time plays an important role and also affects the angle of Mach cone.
Sedimentation, Pclet number, and hydrodynamic screening Kiley Benes,1
Tong, Penger
a is the sphere radius, is the solvent viscosity, g is the accel- eration of gravity, and is the particle. Two functional forms for the sedimentation velocity as a function of particle concen- tration velocity. He assumed i a low particle Reynolds number or the neglect of inertia , ii two- body hydrodynamic
Hydrodynamic analysis of mooring lines based on optical tracking experiments
Yang, Woo Seuk
2009-05-15T23:59:59.000Z
Hydrodynamic Force Coefficients.............................................................................11 1.2.2.1. Deterministic Approach .............................................12 1.2.2.2. Stochastic Approach... Page 2.6. Estimation of Force Transfer Coefficients ...........................................50 2.6.1. Fourier Analysis ......................................................................51 2.6.2. Least Square Minimization...
IDENTIFICATION OF UNDERWATER VEHICLE HYDRODYNAMIC COEFFICIENTS USING FREE
Johansen, Tor Arne
been an ever increasing num- ber of applications for unmanned underwater vehicles (UUV) in variousIDENTIFICATION OF UNDERWATER VEHICLE HYDRODYNAMIC COEFFICIENTS USING FREE DECAY TESTS Andrew Ross the potential accuracy of these new methods. Copyright c 2004 IFAC. Keywords: Low-speed underwater vehicles
Delta Hydrodynamics and Water Salinity with Future Conditions
Pasternack, Gregory B.
, Comparing Futures for the Sacramento-San Joaquin Delta, prepared by a team of researchers from the CenterDelta Hydrodynamics and Water Salinity with Future Conditions Technical Appendix C William E of California All rights reserved San Francisco, CA Short sections of text, not to exceed three paragraphs, may
Hydrodynamic model for picosecond propagation of laser-created nanoplasmas
Saxena, Vikrant; Ziaja, Beata; Santra, Robin
2015-01-01T23:59:59.000Z
The interaction of a free-electron-laser pulse with a moderate or large size cluster is known to create a quasi-neutral nanoplasma, which then expands on hydrodynamic timescale, i.e., $>1$ ps. To have a better understanding of ion and electron data from experiments derived from laser-irradiated clusters, one needs to simulate cluster dynamics on such long timescales for which the molecular dynamics approach becomes inefficient. We therefore propose a two-step Molecular Dynamics-Hydrodynamic scheme. In the first step we use molecular dynamics code to follow the dynamics of an irradiated cluster until all the photo-excitation and corresponding relaxation processes are finished and a nanoplasma, consisting of ground-state ions and thermalized electrons, is formed. In the second step we perform long-timescale propagation of this nanoplasma with a computationally efficient hydrodynamic approach. In the present paper we examine the feasibility of a hydrodynamic two-fluid approach to follow the expansion of spherica...
Three-Dimensional Hydrodynamic Model for Prediction of Falling Cylinder Through Water Column
Chu, Peter C.
1 1 Three-Dimensional Hydrodynamic Model for Prediction of Falling Cylinder Through Water Column-coordinate), cylinder's main-axis following coordinate (M-coordinate), and hydrodynamic force following coordinate (F-coordinate system. The hydrodynamic forces (such as the drag and lift forces) and their moments are easily computed
Mofrad, Mohammad R. K.
, in order to better resolve the drag profiles along the filament. A large part of the hydrodynamic dragAveraged implicit hydrodynamic model of semiflexible filaments Preethi L. Chandran and Mohammad R 2009; published 26 March 2010 We introduce a method to incorporate hydrodynamic interaction in a model
Tests of the hydrodynamic equivalence of direct-drive implosions with different D2 and 3
Tests of the hydrodynamic equivalence of direct-drive implosions with different D2 and 3 He, D2 and 3 He gases are fully ionized, and hydrodynamically equivalent fuels with different ratios the materials are cho- sen to be as nearly hydrodynamically equivalent as possible. D and 3 He have the special
Murray, Richard M.
On the Control of Jump Linear Markov Systems with Markov State Estimation Vijay Gupta, Richard M of such a system and also solve the optimal LQR control problem for the case when the state estimate update uses. As an example of how jump linear Markov systems might be useful to model systems being controlled over a network
Automated high pressure cell for pressure jump x-ray diffraction
Brooks, Nicholas J.; Gauthe, Beatrice L. L. E.; Templer, Richard H.; Ces, Oscar; Seddon, John M. [Department of Chemistry, Imperial College London, South Kensington Campus, London SW7 2AZ (United Kingdom); Terrill, Nick J. [Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom); Rogers, Sarah E. [ISIS, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0QX (United Kingdom)
2010-06-15T23:59:59.000Z
A high pressure cell for small and wide-angle x-ray diffraction measurements of soft condensed matter samples has been developed, incorporating a fully automated pressure generating network. The system allows both static and pressure jump measurements in the range of 0.1-500 MPa. Pressure jumps can be performed as quickly as 5 ms, both with increasing and decreasing pressures. Pressure is generated by a motorized high pressure pump, and the system is controlled remotely via a graphical user interface to allow operation by a broad user base, many of whom may have little previous experience of high pressure technology. Samples are loaded through a dedicated port allowing the x-ray windows to remain in place throughout an experiment; this facilitates accurate subtraction of background scattering. The system has been designed specifically for use at beamline I22 at the Diamond Light Source, United Kingdom, and has been fully integrated with the I22 beamline control systems.
Assessing Thermo-Hydrodynamic-Chemical Processes at the Dixie Valley
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Tisdell, Chris
Massachusetts University Massey University McGill University McMaster University Melbourne University Michigan State University Michigan University Minnesota University Monash University Montpellier UniversityAachen RWTH Aarhus University Aberdeen University Adelaide University Alabama University Alberta
Risk-Sensitive Control of Pure Jump Process on Countable Space with Near Monotone Cost
Suresh Kumar, K., E-mail: suresh@math.iitb.ac.in; Pal, Chandan, E-mail: cpal@math.iitb.ac.in [Indian Institute of Technology Bombay, Department of Mathematics (India)
2013-12-15T23:59:59.000Z
In this article, we study risk-sensitive control problem with controlled continuous time pure jump process on a countable space as state dynamics. We prove multiplicative dynamic programming principle, elliptic and parabolic Harnack’s inequalities. Using the multiplicative dynamic programing principle and the Harnack’s inequalities, we prove the existence and a characterization of optimal risk-sensitive control under the near monotone condition.
Temperature jump in degenerate quantum gases in the presence of a Bose - Einstein condensate
A. V. Latyshev; A. A. Yushkanov
2010-01-04T23:59:59.000Z
We construct a kinetic equation modeling the behavior of degenerate quantum Bose gases whose collision rate depends on the momentum of elementary excitations. We consider the case where the phonon component is the decisive factor in the elementary excitations. We analytically solve the half-space boundary value problem of the temperature jump at the boundary of the degenerate Bose gas in the presence of a Bose -- Einstein condensate.
Galaxies that Shine: radiation-hydrodynamical simulations of disk galaxies
Rosdahl, Joakim; Teyssier, Romain; Agertz, Oscar
2015-01-01T23:59:59.000Z
Radiation feedback is typically implemented using subgrid recipes in hydrodynamical simulations of galaxies. Very little work has so far been performed using radiation-hydrodynamics (RHD), and there is no consensus on the importance of radiation feedback in galaxy evolution. We present RHD simulations of isolated galaxy disks of different masses with a resolution of 18 pc. Besides accounting for supernova feedback, our simulations are the first galaxy-scale simulations to include RHD treatments of photo-ionisation heating and radiation pressure, from both direct optical/UV radiation and multi-scattered, re-processed infrared (IR) radiation. Photo-heating smooths and thickens the disks and suppresses star formation about as much as the inclusion of ("thermal dump") supernova feedback does. These effects decrease with galaxy mass and are mainly due to the prevention of the formation of dense clouds, as opposed to their destruction. Radiation pressure, whether from direct or IR radiation, has little effect, but ...
Enhanced Heat Flow in the Hydrodynamic Collisionless Regime
Meppelink, R.; Rooij, R. van; Vogels, J. M.; Straten, P. van der [Atom Optics and Ultrafast Dynamics, Utrecht University, P.O. Box 80000, 3508 TA Utrecht (Netherlands)
2009-08-28T23:59:59.000Z
We study the heat conduction of a cold, thermal cloud in a highly asymmetric trap. The cloud is axially hydrodynamic, but due to the asymmetric trap radially collisionless. By locally heating the cloud we excite a thermal dipole mode and measure its oscillation frequency and damping rate. We find an unexpectedly large heat conduction compared to the homogeneous case. The enhanced heat conduction in this regime is partially caused by atoms with a high angular momentum spiraling in trajectories around the core of the cloud. Since atoms in these trajectories are almost collisionless they strongly contribute to the heat transfer. We observe a second, oscillating hydrodynamic mode, which we identify as a standing wave sound mode.
Hydrodynamic model of Fukushima-Daiichi NPP Industrial site flooding
Vaschenko, V N; Gerasimenko, T V; Vachev, B
2014-01-01T23:59:59.000Z
While the Fukushima-Daiichi was designed and constructed the maximal tsunami height estimate was about 3 m based on analysis of statistical data including Chile earthquake in 1960. The NPP project industrial site height was 10 m. The further deterministic estimates TPCO-JSCE confirmed the impossibility of the industrial site flooding by a tsunami and therefore confirmed ecological safety of the NPP. However, as a result of beyond design earthquake of 11 March 2011 the tsunami height at the shore near the Fukushima-Daiichi NPP reached 15 m. This led to flooding and severe emergencies having catastrophic environmental consequences. This paper proposes hydrodynamic model of tsunami emerging and traveling based on conservative assumptions. The possibility of a tsunami wave reaching 15 m height at the Fukushima-Daiichi NPP shore was confirmed for deduced hydrodynamic resistance coefficient of 1.8. According to the model developed a possibility of flooding is determined not only by the industrial site height, magni...
Hydrodynamic instabilities in beryllium targets for the National Ignition Facility
Yi, S. A., E-mail: austinyi@lanl.gov; Simakov, A. N.; Wilson, D. C.; Olson, R. E.; Kline, J. L.; Batha, S. H. [Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, New Mexico 87545 (United States); Clark, D. S.; Hammel, B. A.; Milovich, J. L.; Salmonson, J. D.; Kozioziemski, B. J. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551 (United States)
2014-09-15T23:59:59.000Z
Beryllium ablators offer higher ablation velocity, rate, and pressure than their carbon-based counterparts, with the potential to increase the probability of achieving ignition at the National Ignition Facility (NIF) [E. I. Moses et al., Phys. Plasmas 16, 041006 (2009)]. We present here a detailed hydrodynamic stability analysis of low (NIF Revision 6.1) and high adiabat NIF beryllium target designs. Our targets are optimized to fully utilize the advantages of beryllium in order to suppress the growth of hydrodynamic instabilities. This results in an implosion that resists breakup of the capsule, and simultaneously minimizes the amount of ablator material mixed into the fuel. We quantify the improvement in stability of beryllium targets relative to plastic ones, and show that a low adiabat beryllium capsule can be at least as stable at the ablation front as a high adiabat plastic target.
COSMOS: A Radiation-Chemo-Hydrodynamics Code for Astrophysical Problems
Peter Anninos; P. Chris Fragile; Stephen D. Murray
2003-03-10T23:59:59.000Z
We have developed a new massively-parallel radiation-hydrodynamics code (Cosmos) for Newtonian and relativistic astrophysical problems that also includes radiative cooling, self-gravity, and non-equilibrium, multi-species chemistry. Several numerical methods are implemented for the hydrodynamics, including options for both internal and total energy conserving schemes. Radiation is treated using flux-limited diffusion. The chemistry incorporates 27 reactions, including both collisional and radiative processes for atomic hydrogen and helium gases, and molecular hydrogen chains. In this paper we discuss the equations and present results from test problems carried out to verify the robustness and accuracy of our code in the Newtonian regime. An earlier paper presented tests of the relativistic capabilities of Cosmos.
COSMOS A Radiation-Chemo-Hydrodynamics Code for Astrophysical Problems
Anninos, P; Murray, S D; Anninos, Peter; Murray, Stephen D.
2003-01-01T23:59:59.000Z
We have developed a new massively-parallel radiation-hydrodynamics code (Cosmos) for Newtonian and relativistic astrophysical problems that also includes radiative cooling, self-gravity, and non-equilibrium, multi-species chemistry. Several numerical methods are implemented for the hydrodynamics, including options for both internal and total energy conserving schemes. Radiation is treated using flux-limited diffusion. The chemistry incorporates 27 reactions, including both collisional and radiative processes for atomic hydrogen and helium gases, and molecular hydrogen chains. In this paper we discuss the equations and present results from test problems carried out to verify the robustness and accuracy of our code in the Newtonian regime. An earlier paper presented tests of the relativistic capabilities of Cosmos.
Porous Superhydrophobic Membranes: Hydrodynamic Anomaly in Oscillating Flows
Rajauria, Sukumar; Lawall, J; Yakhot, Victor; Ekinci, Kamil L
2011-01-01T23:59:59.000Z
We have fabricated and characterized a novel superhydrophobic system, a mesh-like porous superhydrophobic membrane with solid area fraction $\\Phi_s$, which can maintain intimate contact with outside air and water reservoirs simultaneously. Oscillatory hydrodynamic measurements on porous superhydrophobic membranes as a function of $\\Phi_s$ reveal surprising effects. The hydrodynamic mass oscillating in-phase with the membranes stays constant for $0.9\\le\\Phi_s\\le1$, but drops precipitously for $\\Phi_s < 0.9$. The viscous friction shows a similar drop after a slow initial decrease proportional to $\\Phi_s$. We attribute these effects to the percolation of a stable Knudsen layer of air at the interface.
Porous Superhydrophobic Membranes: Hydrodynamic Anomaly in Oscillating Flows
Sukumar Rajauria; O. Ozsun; J. Lawall; Victor Yakhot; Kamil L. Ekinci
2011-08-05T23:59:59.000Z
We have fabricated and characterized a novel superhydrophobic system, a mesh-like porous superhydrophobic membrane with solid area fraction $\\Phi_s$, which can maintain intimate contact with outside air and water reservoirs simultaneously. Oscillatory hydrodynamic measurements on porous superhydrophobic membranes as a function of $\\Phi_s$ reveal surprising effects. The hydrodynamic mass oscillating in-phase with the membranes stays constant for $0.9\\le\\Phi_s\\le1$, but drops precipitously for $\\Phi_s < 0.9$. The viscous friction shows a similar drop after a slow initial decrease proportional to $\\Phi_s$. We attribute these effects to the percolation of a stable Knudsen layer of air at the interface.
Hydrodynamic analogy of production decline for Devonian shale wells
Pulle, C.V.
1982-01-01T23:59:59.000Z
Several studies on production decline curves have shown that an exponential or hyperbolic curve adequately fits production decline data for Devonian shale wells. Attempts to characterize the production decline based on open flows, rock pressures, and specific shale production mechanisms have also been made. This paper seeks to provide a genesis of the decline curves with the use of a simple hydrodynamic analogy. Some physical factors critical to well productivity are also examined. 4 refs.
Skew and twist resistant hydrodynamic rotary shaft seal
Dietle, Lannie (Sugar Land, TX); Kalsi, Manmohan Singh (Houston, TX)
1999-01-01T23:59:59.000Z
A hydrodynamically lubricated squeeze packing type rotary shaft seal suitable for lubricant retention and environmental exclusion which incorporates one or more resilient protuberances which and cooperate with the gland walls to hold the seal straight in its installation groove in unpressurized and low pressure lubricant retention applications thereby preventing skew-induced wear caused by impingement of abrasive contaminants present in the environment, and which also serve as radial bearings to prevent tipping of the seal within its installation gland.
Skew and twist resistant hydrodynamic rotary shaft seal
Dietle, L.; Kalsi, M.S.
1999-02-23T23:59:59.000Z
A hydrodynamically lubricated squeeze packing type rotary shaft seal suitable for lubricant retention and environmental exclusion which incorporates one or more resilient protuberances which cooperate with the gland walls to hold the seal straight in its installation groove in unpressurized and low pressure lubricant retention applications thereby preventing skew-induced wear caused by impingement of abrasive contaminants present in the environment, and which also serve as radial bearings to prevent tipping of the seal within its installation gland. 14 figs.
Variational Principle of Hydrodynamics and Quantization by Stochastic Process
T. Kodama; T. Koide
2015-01-05T23:59:59.000Z
The well-known hydrodynamical representation of the Schr\\"{o}dinger equation is reformulated by extending the idea of Nelson-Yasue's stochastic variational method. The fluid flow is composed by the two stochastic processes from the past and the future, which are unified naturally by the principle of maximum entropy. We show that this formulation is easily applicable to the quantization of scalar fields.
A multiblob approach to colloidal hydrodynamics with inherent lubrication
Adolfo Vázquez-Quesada; Florencio Balboa Usabiaga; Rafael Delgado-Buscalioni
2014-07-23T23:59:59.000Z
This work presents an intermediate resolution model of the hydrodynamics of colloidal particles based on a mixed Eulerian-Lagrangian formulation. The particle is constructed with a small set of overlapping Peskin's Immersed Boundary kernels (blobs) which are held together by springs to build up a particle impenetrable core. Here, we used 12 blobs placed in the vertexes of an icosahedron with an extra one in its center. Although the particle surface is not explicitly resolved, we show that the short-distance hydrodynamic responses (flow profiles, translational and rotational mobilities, lubrication, etc) agree with spherical colloids and provide consistent effective radii. A remarkable property of the present multiblob model is that it naturally presents a "divergent" lubrication force at finite inter-particle distance. This permits to resolve the large viscosity increase at dense colloidal volume fractions. The intermediate resolution model is able to recover highly non-trivial (many-body) hydrodynamics using small particles whose radii are similar to the grid size $h$ (in the range $[1.6-3.2]\\,h$). Considering that the cost of the embedding fluid phase scales like the cube of the particle radius, this result brings about a significant computational speed-up. Our code Fluam works in Graphics Processor Units (GPU's) and uses Fast Fourier Transform for the Poisson solver, which further improves its efficiency.
From Field Theory to the Hydrodynamics of Relativistic Superfluids
Stephan Stetina
2015-01-31T23:59:59.000Z
The hydrodynamic description of a superfluid is usually based on a two-fluid picture. In this thesis, basic properties of such a relativistic two-fluid system are derived from the underlying microscopic physics of a complex scalar quantum field theory. To obtain analytic results of all non-dissipative hydrodynamic quantities in terms of field theoretic variables, calculations are first carried out in a low-temperature and weak-coupling approximation. In a second step, the 2-particle-irreducible formalism is applied: This formalism allows for a numerical evaluation of the hydrodynamic parameters for all temperatures below the critical temperature. In addition, a system of two coupled superfluids is studied. As an application, the velocities of first and second sound in the presence of a superflow are calculated. The results show that first (second) sound evolves from a density (temperature) wave at low temperatures to a temperature (density) wave at high temperatures. This role reversal is investigated for ultra-relativistic and near-nonrelativistic systems for zero and nonzero superflow. The studies carried out in this thesis are of a very general nature as one does not have to specify the system for which the microscopic field theory is an effective description. As a particular example, superfluidity in dense quark and nuclear matter in compact stars are discussed.
Jump Chaotic Behaviour of Ultra Low Loss Bulk Acoustic Wave Cavities
Maxim Goryachev; Warrick G. Farr; Serge Galliou; Michael E. Tobar
2014-06-16T23:59:59.000Z
We demonstrate a previously unobserved nonlinear phenomenon in an ultra-low loss quartz Bulk Acoustic Wave cavity ($Q>3\\times10^9$), which only occurs below 20 milli-Kelvin in temperature and under relatively weak pumping. The phenomenon reveals the emergence of several stable equilibria (at least two foci and two nodes) and jumps between these quasi states at random times. The degree of this randomness as well as separations between levels can be controlled by the frequency of the incident carrier signal. It is demonstrated that the nature of the effect lays beyond the standard Duffing model.
Jump chaotic behaviour of ultra low loss bulk acoustic wave cavities
Goryachev, Maxim, E-mail: maxim.goryachev@uwa.edu.au; Farr, Warrick G.; Tobar, Michael E. [ARC Centre of Excellence for Engineered Quantum Systems, University of Western Australia, 35 Stirling Highway, Crawley WA 6009 (Australia); Galliou, Serge [Department of Time and Frequency, FEMTO-ST Institute, ENSMM, 26 Chemin de l'Épitaphe 25000 Besançon (France)
2014-08-11T23:59:59.000Z
We demonstrate a previously unobserved nonlinear phenomenon in an ultra-low loss quartz bulk acoustic wave cavity (Q>3>10{sup 9}), which only occurs below 20 mK in temperature and under relatively weak pumping. The phenomenon reveals the emergence of several stable equilibria (at least two foci and two nodes) and jumps between these quasi states at random times. The degree of this randomness as well as separations between levels can be controlled by the frequency of the incident carrier signal. It is demonstrated that the nature of the effect lies beyond the standard Duffing model.
The jump-off velocity of an impulsively loaded spherical shell
Chabaud, Brandon M. [Los Alamos National Laboratory; Brock, Jerry S. [Los Alamos National Laboratory
2012-04-13T23:59:59.000Z
We consider a constant temperature spherical shell of isotropic, homogeneous, linearly elastic material with density {rho} and Lame coefficients {lambda} and {mu}. The inner and outer radii of the shell are r{sub i} and r{sub o}, respectively. We assume that the inside of the shell is a void. On the outside of the shell, we apply a uniform, time-varying pressure p(t). We also assume that the shell is initially at rest. We want to compute the jump-off time and velocity of the pressure wave, which are the first time after t = 0 at which the pressure wave from the outer surface reaches the inner surface. This analysis computes the jump-off velocity and time for both compressible and incompressible materials. This differs substantially from [3], where only incompressible materials are considered. We will consider the behavior of an impulsively loaded, exponentially decaying pressure wave p(t) = P{sub 0{sup e}}{sup -{alpha}t}, where {alpha} {ge} 0. We notice that a constant pressure wave P(t) = P{sub 0} is a special case ({alpha} = 0) of a decaying pressure wave. Both of these boundary conditions are considered in [3].
Dao, Ming
2006-01-01T23:59:59.000Z
) comparison of indentation creep curve (ICC) right after load jumping and that for the corresponding constant-load on the load-jump tests of AlMg solidsolution alloy using instrumented indentation technique H. Takagia,, M January 2006 Abstract Constant-load tests and load-jump tests were carried out using a microindenter in Al
University of Southern California-Energy Institute | Open Energy
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University of Strathclyde Dpt of Electric Electrical Engineering Institute
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Xueke Pu; Boling Guo
2015-04-21T23:59:59.000Z
The hydrodynamic equations with quantum effects are studied in this paper. First we establish the global existence of smooth solutions with small initial data and then in the second part, we establish the convergence of the solutions of the quantum hydrodynamic equations to those of the classical hydrodynamic equations. The energy equation is considered in this paper, which added new difficulties to the energy estimates, especially to the selection of the appropriate Sobolev spaces.
RAM: a Relativistic Adaptive Mesh Refinement Hydrodynamics Code
Zhang, Wei-Qun; /KIPAC, Menlo Park; MacFadyen, Andrew I.; /Princeton, Inst. Advanced Study
2005-06-06T23:59:59.000Z
The authors have developed a new computer code, RAM, to solve the conservative equations of special relativistic hydrodynamics (SRHD) using adaptive mesh refinement (AMR) on parallel computers. They have implemented a characteristic-wise, finite difference, weighted essentially non-oscillatory (WENO) scheme using the full characteristic decomposition of the SRHD equations to achieve fifth-order accuracy in space. For time integration they use the method of lines with a third-order total variation diminishing (TVD) Runge-Kutta scheme. They have also implemented fourth and fifth order Runge-Kutta time integration schemes for comparison. The implementation of AMR and parallelization is based on the FLASH code. RAM is modular and includes the capability to easily swap hydrodynamics solvers, reconstruction methods and physics modules. In addition to WENO they have implemented a finite volume module with the piecewise parabolic method (PPM) for reconstruction and the modified Marquina approximate Riemann solver to work with TVD Runge-Kutta time integration. They examine the difficulty of accurately simulating shear flows in numerical relativistic hydrodynamics codes. They show that under-resolved simulations of simple test problems with transverse velocity components produce incorrect results and demonstrate the ability of RAM to correctly solve these problems. RAM has been tested in one, two and three dimensions and in Cartesian, cylindrical and spherical coordinates. they have demonstrated fifth-order accuracy for WENO in one and two dimensions and performed detailed comparison with other schemes for which they show significantly lower convergence rates. Extensive testing is presented demonstrating the ability of RAM to address challenging open questions in relativistic astrophysics.
Hydrodynamic and Ecological Assessment of Nearshore Restoration: A Modeling Study
Yang, Zhaoqing; Sobocinski, Kathryn L.; Heatwole, Danelle W.; Khangaonkar, Tarang; Thom, Ronald M.; Fuller, Roger
2010-04-10T23:59:59.000Z
Along the Pacific Northwest coast, much of the estuarine habitat has been diked over the last century for agricultural land use, residential and commercial development, and transportation corridors. As a result, many of the ecological processes and functions have been disrupted. To protect coastal habitats that are vital to aquatic species, many restoration projects are currently underway to restore the estuarine and coastal ecosystems through dike breaches, setbacks, and removals. Information on physical processes and hydrodynamic conditions are critical for the assessment of the success of restoration actions. Restoration of a 160- acre property at the mouth of the Stillaguamish River in Puget Sound has been proposed. The goal is to restore native tidal habitats and estuary-scale ecological processes by removing the dike. In this study, a three-dimensional hydrodynamic model was developed for the Stillaguamish River estuary to simulate estuarine processes. The model was calibrated to observed tide, current, and salinity data for existing conditions and applied to simulate the hydrodynamic responses to two restoration alternatives. Responses were evaluated at the scale of the restoration footprint. Model data was combined with biophysical data to predict habitat responses at the site. Results showed that the proposed dike removal would result in desired tidal flushing and conditions that would support four habitat types on the restoration footprint. At the estuary scale, restoration would substantially increase the proportion of area flushed with freshwater (< 5 ppt) at flood tide. Potential implications of predicted changes in salinity and flow dynamics are discussed relative to the distribution of tidal marsh habitat.
A Moving Frame Algorithm for High Mach Number Hydrodynamics
Hy Trac; Ue-Li Pen
2003-09-24T23:59:59.000Z
We present a new approach to Eulerian computational fluid dynamics that is designed to work at high Mach numbers encountered in astrophysical hydrodynamic simulations. The Eulerian fluid conservation equations are solved in an adaptive frame moving with the fluid where Mach numbers are minimized. The moving frame approach uses a velocity decomposition technique to define local kinetic variables while storing the bulk kinetic components in a smoothed background velocity field that is associated with the grid velocity. Gravitationally induced accelerations are added to the grid, thereby minimizing the spurious heating problem encountered in cold gas flows. Separately tracking local and bulk flow components allows thermodynamic variables to be accurately calculated in both subsonic and supersonic regions. A main feature of the algorithm, that is not possible in previous Eulerian implementations, is the ability to resolve shocks and prevent spurious heating where both the preshock and postshock Mach numbers are high. The hybrid algorithm combines the high resolution shock capturing ability of the second-order accurate Eulerian TVD scheme with a low-diffusion Lagrangian advection scheme. We have implemented a cosmological code where the hydrodynamic evolution of the baryons is captured using the moving frame algorithm while the gravitational evolution of the collisionless dark matter is tracked using a particle-mesh N-body algorithm. The MACH code is highly suited for simulating the evolution of the IGM where accurate thermodynamic evolution is needed for studies of the Lyman alpha forest, the Sunyaev-Zeldovich effect, and the X-ray background. Hydrodynamic and cosmological tests are described and results presented. The current code is fast, memory-friendly, and parallelized for shared-memory machines.
Chemo -- Dynamical evolution of disk galaxies, smoothed particles hydrodynamics approach
Peter Berczik
1998-10-20T23:59:59.000Z
A new Chemo -- Dynamical Smoothed Particle Hydrodynamic (CD -- SPH) code is presented. The disk galaxy is described as a multi -- fragmented gas and star system, embedded into the cold dark matter halo. The star formation (SF) process, SNII, SNIa and PN events as well as chemical enrichment of gas have been considered within the framework of standard SPH model. Using this model we try to describe the dynamical and chemical evolution of triaxial disk -- like galaxies. It is found that such approach provides a realistic description of the process of formation, chemical and dynamical evolution of disk galaxies over the cosmological timescale.
SPLASH: An interactive visualisation tool for Smoothed Particle Hydrodynamics simulations
Daniel J. Price
2007-09-06T23:59:59.000Z
This paper presents SPLASH, a publicly available interactive visualisation tool for Smoothed Particle Hydrodynamics (SPH) simulations. Visualisation of SPH data is more complicated than for grid-based codes because the data is defined on a set of irregular points and therefore requires a mapping procedure to a two dimensional pixel array. This means that, in practise, many authors simply produce particle plots which offer a rather crude representation of the simulation output. Here we describe the techniques and algorithms which are utilised in SPLASH in order to provide the user with a fast, interactive and meaningful visualisation of one, two and three dimensional SPH results.
Role of Brownian Motion Hydrodynamics on Nanofluid Thermal Conductivity
W Evans, J Fish, P Keblinski
2005-11-14T23:59:59.000Z
We use a simple kinetic theory based analysis of heat flow in fluid suspensions of solid nanoparticles (nanofluids) to demonstrate that the hydrodynamics effects associated with Brownian motion have a minor effect on the thermal conductivity of the nanofluid. Our conjecture is supported by the results of molecular dynamics simulations of heat flow in a model nanofluid with well-dispersed particles. Our findings are consistent with the predictions of the effective medium theory as well as with recent experimental results on well dispersed metal nanoparticle suspensions.
Hydrodynamic Modes of a holographic $p-$ wave superfluid
Raul E. Arias; Ignacio Salazar Landea
2014-11-04T23:59:59.000Z
In this work we analyze the hydrodynamics of a $p-$ wave superfluid on its strongly coupled regime by considering its holographic description. We obtain the poles of the retarded Green function through the computation of the quasi-normal modes of the dual AdS black hole background finding diffusive, pseudo-diffusive and sound modes. For the sound modes we compute the speed of sound and its attenuation as function of the temperature. For the diffusive and pseudo-diffusive modes we find that they acquire a non-zero real part at certain finite momentum.
Electron magneto-hydrodynamic waves bounded by magnetic bubble
Anitha, V. P.; Sharma, D.; Banerjee, S. P.; Mattoo, S. K. [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India)
2012-08-15T23:59:59.000Z
The propagation of electron magneto-hydrodynamic (EMHD) waves is studied experimentally in a 3-dimensional region of low magnetic field surrounded by stronger magnetic field at its boundaries. We report observations where bounded left hand polarized Helicon like EMHD waves are excited, localized in the region of low magnetic field due to the boundary effects generated by growing strengths of the ambient magnetic field rather than a conducting or dielectric material boundary. An analytical model is developed to include the effects of radially nonuniform magnetic field in the wave propagation. The bounded solutions are compared with the experimentally obtained radial wave magnetic field profiles explaining the observed localized propagation of waves.
Skew And Twist Resistant Hydrodynamic Rotary Shaft Seal
Dietle, Lannie (Sugar Land, TX); Kalsi, Manmohan Singh (Houston, TX)
2000-03-14T23:59:59.000Z
A hydrodynamically lubricated squeeze packing type rotary shaft seal suitable for lubricant retention and environmental exclusion which incorporates one or more resilient protuberances which and cooperate with the gland walls to hold the seal straight in its installation groove in unpressurized and low pressure lubricant retention applications thereby preventing skew-induced wear caused by impingement of abrasive contaminants present in the environment, and which also serve as radial bearings to prevent tipping of the seal within its installation gland. Compared to prior art, this invention provides a dramatic reduction of seal and shaft wear in abrasive environments and provides a significant increase in seal life.
Dancing Volvox: Hydrodynamic Bound States of Swimming Algae
Knut Drescher; Kyriacos C. Leptos; Idan Tuval; Takuji Ishikawa; Timothy J. Pedley; Raymond E. Goldstein
2009-01-14T23:59:59.000Z
The spherical alga Volvox swims by means of flagella on thousands of surface somatic cells. This geometry and its large size make it a model organism for studying the fluid dynamics of multicellularity. Remarkably, when two nearby Volvox swim close to a solid surface, they attract one another and can form stable bound states in which they "waltz" or "minuet" around each other. A surface-mediated hydrodynamic attraction combined with lubrication forces between spinning, bottom-heavy Volvox explains the formation, stability and dynamics of the bound states. These phenomena are suggested to underlie observed clustering of Volvox at surfaces.
Semiclassical hydrodynamics of a quantum Kane model for semiconductors
Luigi Barletti; Giovanni Borgioli; Giovanni Frosali
2014-02-17T23:59:59.000Z
In this paper we derive a semiclassical hydrodynamic system for electron densities and currents in the two energy bands of a semiconductor. We use the semiclassical Wigner equation with a k.p Hamiltonian and a BGK dissipative term to construct the first two moment equations. The closure of the moment system is obtained using the Maximum Entropy Principle, by minimizing a Gibbs free-energy functional under suitable constraints. We prove that the constraint equations can be uniquely solved, i.e. that the local equilibrium state can be parametrized by the density and velocity field. Some BGK-like models are proposed to mimic the quantum interband migration.
Hydrodynamic Focusing Micropump Module with PDMS/Nickel Particle
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Hydrodynamic experiment provides key data for Stockpile Stewardship
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Limiting results for the free energy of directed polymers in random environment with unbounded jumps
Francis Comets; Ryoki Fukushima; Shuta Nakajima; Nobuo Yoshida
2015-04-17T23:59:59.000Z
We study asymptotic behaviors of the free energy for the directed polymer in random environment. The polymer is allowed to make unbounded jumps and the environment is given by the Bernoulli variables. We first establish the existence and continuity including the negative infinity value of the coupling constant $\\beta$. Our proof of existence at $\\beta=-\\infty$ differs from existing ones in that it avoids the direct use of subadditivity. Secondly, we identify the asymptotics of the free energy at $\\beta=-\\infty$ in the limit of the success probability of the Bernoulli variables tending to one. It is described by using the so-called time constant of a certain directed first passage percolation. Our proof relies on a certain continuity property of the time constant, which is of independent interest.
Limiting results for the free energy of directed polymers in random environment with unbounded jumps
Francis Comets; Ryoki Fukushima; Shuta Nakajima; Nobuo Yoshida
2015-05-27T23:59:59.000Z
We study asymptotic behaviors of the free energy for the directed polymer in random environment. The polymer is allowed to make unbounded jumps and the environment is given by the Bernoulli variables. We first establish the existence and continuity including the negative infinity value of the coupling constant $\\beta$. Our proof of existence at $\\beta=-\\infty$ differs from existing ones in that it avoids the direct use of subadditivity. Secondly, we identify the asymptotics of the free energy at $\\beta=-\\infty$ in the limit of the success probability of the Bernoulli variables tending to one. It is described by using the so-called time constant of a certain directed first passage percolation. Our proof relies on a certain continuity property of the time constant, which is of independent interest.
Hydrodynamics of rapidly rotating superfluid neutron stars with mutual friction
A. Passamonti; N. Andersson
2010-04-26T23:59:59.000Z
We study time evolutions of superfluid neutron stars, focussing on the nature of the oscillation spectrum, the effect of mutual friction force on the oscillations and the hydrodynamical spin-up phase of pulsar glitches. We linearise the dynamical equations of a Newtonian two-fluid model for rapidly rotating backgrounds. In the axisymmetric equilibrium configurations, the two fluid components corotate and are in beta-equilibrium. We use analytical equations of state that generate stratified and non-stratified stellar models, which enable us to study the coupling between the dynamical degrees of freedom of the system. By means of time evolutions of the linearised dynamical equations, we determine the spectrum of axisymmetric and non-axisymmetric oscillation modes, accounting for the contribution of the gravitational potential perturbations, i.e. without adopting the Cowling approximation. We study the mutual friction damping of the superfluid oscillations and consider the effects of the non-dissipative part of the mutual friction force on the mode frequencies. We also provide technical details and relevant tests for the hydrodynamical model of pulsar glitches discussed by Sidery, Passamonti and Andersson (2010). In particular, we describe the method used to generate the initial data that mimic the pre-glitch state, and derive the equations that are used to extract the gravitational-wave signal.
Hydrodynamic model for electron-hole plasma in graphene
D. Svintsov; V. Vyurkov; S. Yurchenko; T. Otsuji; V. Ryzhii
2012-01-03T23:59:59.000Z
We propose a hydrodynamic model describing steady-state and dynamic electron and hole transport properties of graphene structures which accounts for the features of the electron and hole spectra. It is intended for electron-hole plasma in graphene characterized by high rate of intercarrier scattering compared to external scattering (on phonons and impurities), i.e., for intrinsic or optically pumped (bipolar plasma), and gated graphene (virtually monopolar plasma). We demonstrate that the effect of strong interaction of electrons and holes on their transport can be treated as a viscous friction between the electron and hole components. We apply the developed model for the calculations of the graphene dc conductivity, in particular, the effect of mutual drag of electrons and holes is described. The spectra and damping of collective excitations in graphene in the bipolar and monopolar limits are found. It is shown that at high gate voltages and, hence, at high electron and low hole densities (or vice-versa), the excitations are associated with the self-consistent electric field and the hydrodynamic pressure (plasma waves). In intrinsic and optically pumped graphene, the waves constitute quasineutral perturbations of the electron and hole densities (electron-hole sound waves) with the velocity being dependent only on the fundamental graphene constants.
Hydrodynamic Simulation of Supernova Remnants Including Efficient Particle Acceleration
Donald C. Ellison; Anne Decourchelle; Jean Ballet
2003-08-19T23:59:59.000Z
A number of supernova remnants (SNRs) show nonthermal X-rays assumed to be synchrotron emission from shock accelerated TeV electrons. The existence of these TeV electrons strongly suggests that the shocks in SNRs are sources of galactic cosmic rays (CRs). In addition, there is convincing evidence from broad-band studies of individual SNRs and elsewhere that the particle acceleration process in SNRs can be efficient and nonlinear. If SNR shocks are efficient particle accelerators, the production of CRs impacts the thermal properties of the shock heated, X-ray emitting gas and the SNR evolution. We report on a technique that couples nonlinear diffusive shock acceleration, including the backreaction of the accelerated particles on the structure of the forward and reverse shocks, with a hydrodynamic simulation of SNR evolution. Compared to models which ignore CRs, the most important hydrodynamical effects of placing a significant fraction of shock energy into CRs are larger shock compression ratios and lower temperatures in the shocked gas. We compare our results, which use an approximate description of the acceleration process, with a more complete model where the full CR transport equations are solved (i.e., Berezhko et al., 2002), and find excellent agreement for the CR spectrum summed over the SNR lifetime and the evolving shock compression ratio. The importance of the coupling between particle acceleration and SNR dynamics for the interpretation of broad-band continuum and thermal X-ray observations is discussed.
Hydrodynamic and hydromagnetic energy spectra from large eddy simulations
N. E. L. Haugen; A. Brandenburg
2006-06-29T23:59:59.000Z
Direct and large eddy simulations of hydrodynamic and hydromagnetic turbulence have been performed in an attempt to isolate artifacts from real and possibly asymptotic features in the energy spectra. It is shown that in a hydrodynamic turbulence simulation with a Smagorinsky subgrid scale model using 512^3 meshpoints two important features of the 4096^3 simulation on the Earth simulator (Kaneda et al. 2003, Phys. Fluids 15, L21) are reproduced: a k^{-0.1} correction to the inertial range with a k^{-5/3} Kolmogorov slope and the form of the bottleneck just before the dissipative subrange. Furthermore, it is shown that, while a Smagorinsky-type model for the induction equation causes an artificial and unacceptable reduction in the dynamo efficiency, hyper-resistivity yields good agreement with direct simulations. In the large-scale part of the inertial range, an excess of the spectral magnetic energy over the spectral kinetic energy is confirmed. However, a trend towards spectral equipartition at smaller scales in the inertial range can be identified. With magnetic fields, no explicit bottleneck effect is seen.
The dynamics of polymers in solution with hydrodynamic memory
V. Lisy; J. Tothova; B. Brutovsky; A. V Zatovsky
2005-09-15T23:59:59.000Z
The theory of the dynamics of polymers in solution is developed coming from the hydrodynamic theory of the Brownian motion (BM) and the Rouse-Zimm (RZ) model. It is shown that the time correlation functions describing the polymer motion essentially differ from those in the previous RZ models based on the Einstein theory of BM. The MSD of the polymer coil is at short times proportional to t^2 (instead of t). At long times it contains additional (to the Einstein term) contributions, the leading of which is ~ t^{1/2}. The relaxation of the internal normal modes of the polymer differs from the traditional exponential decay. This is displayed in the tails of their correlation functions, the longest-lived being ~ t^{-3/2} in the Rouse limit and t^{-5/2} in the Zimm case when the hydrodynamic interaction is strong. It is discussed that the found peculiarities, in particular a slower diffusion of the coil, should be observable in dynamic scattering experiments. The dynamic structure factor and the first cumulant of the polymer coil are calculated. The theory is extended to the situation when the dynamics of the studied polymer is influenced by the presence of other polymers in dilute solution.
Dynamic mesoscale model of dipolar fluids via fluctuating hydrodynamics
Persson, Rasmus A. X.; Chu, Jhih-Wei, E-mail: jwchu@nctu.edu.tw [Institute of Bioinformatics and Systems Biology, National Chiao Tung University, Hsinchu 30068, Taiwan (China); Department of Biological Science and Technology, National Chiao Tung University, Hsinchu 30068, Taiwan (China); Voulgarakis, Nikolaos K. [Department of Mathematics, Washington State University, Richland, Washington 99372 (United States)
2014-11-07T23:59:59.000Z
Fluctuating hydrodynamics (FHD) is a general framework of mesoscopic modeling and simulation based on conservational laws and constitutive equations of linear and nonlinear responses. However, explicit representation of electrical forces in FHD has yet to appear. In this work, we devised an Ansatz for the dynamics of dipole moment densities that is linked with the Poisson equation of the electrical potential ? in coupling to the other equations of FHD. The resulting ?-FHD equations then serve as a platform for integrating the essential forces, including electrostatics in addition to hydrodynamics, pressure-volume equation of state, surface tension, and solvent-particle interactions that govern the emergent behaviors of molecular systems at an intermediate scale. This unique merit of ?-FHD is illustrated by showing that the water dielectric function and ion hydration free energies in homogeneous and heterogenous systems can be captured accurately via the mesoscopic simulation. Furthermore, we show that the field variables of ?-FHD can be mapped from the trajectory of an all-atom molecular dynamics simulation such that model development and parametrization can be based on the information obtained at a finer-grained scale. With the aforementioned multiscale capabilities and a spatial resolution as high as 5 Å, the ?-FHD equations represent a useful semi-explicit solvent model for the modeling and simulation of complex systems, such as biomolecular machines and nanofluidics.
Bulk Viscosity and Cavitation in Boost-Invariant Hydrodynamic Expansion
Krishna Rajagopal; Nilesh Tripuraneni
2010-02-16T23:59:59.000Z
We solve second order relativistic hydrodynamics equations for a boost-invariant 1+1-dimensional expanding fluid with an equation of state taken from lattice calculations of the thermodynamics of strongly coupled quark-gluon plasma. We investigate the dependence of the energy density as a function of proper time on the values of the shear viscosity, the bulk viscosity, and second order coefficients, confirming that large changes in the values of the latter have negligible effects. Varying the shear viscosity between zero and a few times s/(4 pi), with s the entropy density, has significant effects, as expected based on other studies. Introducing a nonzero bulk viscosity also has significant effects. In fact, if the bulk viscosity peaks near the crossover temperature Tc to the degree indicated by recent lattice calculations in QCD without quarks, it can make the fluid cavitate -- falling apart into droplets. It is interesting to see a hydrodynamic calculation predicting its own breakdown, via cavitation, at the temperatures where hadronization is thought to occur in ultrarelativistic heavy ion collisions.
University of Minnesota (NorthernSTAR Building America Partnership) | Open
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are being directedAnnualProperty Edit withTianlin BaxinUmwelt Management AG UMaAGUnitilMichigan Hydrodynamics Jump
Category:Hydrodynamic Testing Facility Type | Open Energy Information
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are beingZealand JumpConceptual Model, click here. Category:Conceptual Model Add.pngpage?sourcehelp is welcomed.This
THERMO-HYDRODYNAMICS OF DEVELOPING FLOW IN A RECTANGULAR MINI-CHANNEL ARRAY Gaurav Agarwal
Khandekar, Sameer
THERMO-HYDRODYNAMICS OF DEVELOPING FLOW IN A RECTANGULAR MINI-CHANNEL ARRAY Gaurav Agarwal Dept of Technology Kanpur Kanpur (UP) 208016, India samkhan@iitk.ac.in ABSTRACT Thermo-hydrodynamic performance on developing flows. Thus, the study reveals that conventional theory, which predicts thermo
Coupling upland watershed and downstream waterbody hydrodynamic and water quality models
. Such models lack the capacity to simulate the hydrodynamics and water quality processes of larger waterCoupling upland watershed and downstream waterbody hydrodynamic and water quality models (SWAT and CE-QUAL-W2) for better water resources management in complex river basins B. Debele & R. Srinivasan
An Investigation on the Hydrodynamics and Sediment Dynamics on an Intertidal Mudflat in
Talke, Stefan
An Investigation on the Hydrodynamics and Sediment Dynamics on an Intertidal Mudflat in Central San on the Hydrodynamics and Sediment Dynamics on an Intertidal Mudflat in Central San Francisco Bay Copyright 2005 on an Intertidal Mudflat in Central San Francisco Bay by Stefan Andreas Talke Doctor of Philosophy in Engineering
Role of Brownian motion hydrodynamics on nanofluid thermal conductivity William Evans
Fish, Jacob
Role of Brownian motion hydrodynamics on nanofluid thermal conductivity William Evans Lockheed of solid nanoparticles nanofluids to demonstrate that the hydrodynamics effects associated with Brownian motion have only a minor effect on the thermal conductivity of the nanofluid. This analysis is supported
Michigan State University | Open Energy Information
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are beingZealand Jump to: navigation, searchOfRose BendMiasole Inc Jump to: navigation, search Name:State University
PLANET FORMATION IN HIGHLY INCLINED BINARY SYSTEMS. I. PLANETESIMALS JUMP INWARD AND PILE UP
Xie Jiwei; Zhou Jilin [Department of Astronomy and Key Laboratory of Modern Astronomy and Astrophysics in Ministry of Education, Nanjing University, 210093 (China); Payne, Matthew J.; Ge Jian [Department of Astronomy, University of Florida, Gainesville, FL 32611-2055 (United States); Thebault, Philippe, E-mail: xiejiwei@gmail.com [Observatoire de Paris, Section de Meudon, F-92195 Meudon Principal Cedex (France)
2011-07-01T23:59:59.000Z
Most detected planet-bearing binaries are in wide orbits, for which a high inclination, i{sub B} , between the binary orbital plane and the plane of the planetary disk around the primary is likely to be common. In this paper, we investigate the intermediate stages-from planetesimals to planetary embryos/cores-of planet formation in such highly inclined cases. Our focus is on the effects of gas drag on the planetesimals' orbital evolution, in particular on the evolution of the planetesimals' semimajor axis distribution and their mutual relative velocities. We first demonstrate that a non-evolving axisymmetric disk model is a good approximation for studying the effects of gas drag on a planetesimal in the highly inclined case (30 deg. < i{sub B} < 150 deg.). We then find that gas drag plays a crucial role, and the results can be generally divided into two categories, i.e., the Kozai-on regime and the Kozai-off regime, depending on the specific value of i{sub B} . For both regimes, a robust outcome over a wide range of parameters is that planetesimals migrate/jump inward and pile up, leading to a severely truncated and dense planetesimal disk around the primary. In this compact and dense disk, collision rates are high but relative velocities are low, providing conditions that are favorable for planetesimal growth and potentially allow for the subsequent formation of planets.
Quenched Invariance Principle for a class of random conductance models with long-range jumps
Marek Biskup; Takashi Kumagai
2014-12-10T23:59:59.000Z
We study random walks on $\\mathbb Z^d$ among random conductances $\\{C_{xy}\\colon x,y\\in\\mathbb Z^d\\}$ that permit jumps of arbitrary length. Apart from joint ergodicity with respect to spatial shifts, we assume only that the nearest-neighbor conductances are uniformly positive and that $\\sum_{x\\in\\mathbb Z^d} C_{0x}|x|^2$ is integrable. Our focus is on the Quenched Invariance Principle (QIP) which we establish in all $d\\ge3$ by a combination of corrector methods and heat-kernel technology. In particular, a QIP thus holds for random walks on long-range percolation graphs with exponents larger than $d+2$ in all $d\\ge3$, provided all nearest-neighbor edges are present. We then show that, for long-range percolation with exponents between $d+2$ and $2d$, the corrector fails to be sublinear everywhere. Similar examples are constructed also for nearest-neighbor, ergodic conductances in $d\\ge4$ under the conditions close to, albeit not exactly, complementary to those of the recent work of S. Andres, M. Slowik and J.-D. Deuschel.
Adrian A. Budini
2010-05-20T23:59:59.000Z
In this paper, we develop a quantum-jump approach for describing the photon-emission process of single fluorophore systems coupled to complex classically fluctuating reservoirs. The formalism relies on an open quantum system approach where the dynamic of the system and the reservoir fluctuations are described through a density matrix whose evolution is defined by a Lindblad rate equation. For each realization of the photon measurement processes it is possible to define a conditional system state (stochastic density matrix) whose evolution depends on both the photon detection events and the fluctuations between the configurational states of the reservoir. In contrast to standard fluorescent systems the photon-to-photon emission process is not a renewal one, being defined by a (stochastic) waiting time distribution that in each recording event parametrically depends on the conditional state. The formalism allows calculating experimental observables such as the full hierarchy of joint probabilities associated to the time intervals between consecutive photon recording events. These results provide a powerful basis for characterizing different situations arising in single-molecule spectroscopy, such as spectral fluctuations, lifetime fluctuations, and light assisted processes.
Fringe jump analysis and electronic corrections for the Tore Supra far infrared interferometer
Gil, C.; Barbuti, A.; Elbeze, D.; Pastor, P.; Philip, J.; Toulouse, L. [CEA, IRFM, F-13108 Saint Paul Lez Durance (France)
2008-10-15T23:59:59.000Z
On the Tore Supra tokamak, the ten-channel far infrared interferometer consists of a double color (119 and 195 {mu}m) system with two detectors for each channel to measure the plasma density. The phase measurement is obtained by combining a 100 kHz shifted reference beam with the probing beam that has crossed the plasma. The achieved precision--a few percent of a fringe--is very good compared with the expected variations due to plasma, which are on the order of several fringes. However, the counting of the fringe variations can be affected when the signal is perturbed by electromagnetic interferences or when it deviates in the presence of strong plasma refraction changes occurring during ICRH breakdowns, pellet injections, or disruptions. This induces a strong decrease in the reliability of the measurement, which is an important concern when the diagnostic is used for density control. We describe in this paper the renewing of the electronics that has been achieved to reduce and correct the number of the so-called fringe jumps. A new zero crossing method for phase measurement is used, together with a field programable gate array semiconductor integration, to measure the phase and activate the algorithm of corrections every 10 {mu}s. Comparisons between a numerical oscilloscope analysis and the corrected acquired data in the case of laboratory amplitude modulation tests and in the case of real plasma perturbations are also discussed.
Hydro-dynamical models for the chaotic dripping faucet
P. Coullet; L. Mahadevan; C. S. Riera
2004-08-20T23:59:59.000Z
We give a hydrodynamical explanation for the chaotic behaviour of a dripping faucet using the results of the stability analysis of a static pendant drop and a proper orthogonal decomposition (POD) of the complete dynamics. We find that the only relevant modes are the two classical normal forms associated with a Saddle-Node-Andronov bifurcation and a Shilnikov homoclinic bifurcation. This allows us to construct a hierarchy of reduced order models including maps and ordinary differential equations which are able to qualitatively explain prior experiments and numerical simulations of the governing partial differential equations and provide an explanation for the complexity in dripping. We also provide a new mechanical analogue for the dripping faucet and a simple rationale for the transition from dripping to jetting modes in the flow from a faucet.
A Co-moving Coordinate System for Relativistic Hydrodynamics
Scott Pratt
2006-12-03T23:59:59.000Z
The equations of relativistic hydrodynamics are transformed so that steps forward in time preserves local simultaneity. In these variables, the space-time coordinates of neighboring points on the mesh are simultaneous according to co-moving observers. Aside from the time step varying as a function of the location on the mesh, the local velocity gradient and the local density then evolve according to non-relativistic equations of motion. Analytic solutions are found for two one-dimensional cases with constant speed of sound. One solution has a Gaussian density profile when mapped into the new coordinates. That solution is analyzed for the effects of longitudinal acceleration in relativistic heavy ion collisions at RHIC, especially in regards to two-particle correlation measurements of the longitudinal size.
Black brane entropy and hydrodynamics: The boost-invariant case
Booth, Ivan; Heller, Michal P.; Spalinski, Michal [Department of Mathematics and Statistics, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, A1C 5S7 (Canada); Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Cracow (Poland); Soltan Institute for Nuclear Studies, 00-681 Warsaw (Poland) and Physics Department, University of Bialystok, 15-424 Bialystok (Poland)
2009-12-15T23:59:59.000Z
The framework of slowly evolving horizons is generalized to the case of black branes in asymptotically anti-de Sitter spaces in arbitrary dimensions. The results are used to analyze the behavior of both event and apparent horizons in the gravity dual to boost-invariant flow. These considerations are motivated by the fact that at second order in the gradient expansion the hydrodynamic entropy current in the dual Yang-Mills theory appears to contain an ambiguity. This ambiguity, in the case of boost-invariant flow, is linked with a similar freedom on the gravity side. This leads to a phenomenological definition of the entropy of black branes. Some insights on fluid/gravity duality and the definition of entropy in a time-dependent setting are elucidated.
Absolute Lineshifts - A new diagnostic for stellar hydrodynamics
Dainis Dravins
2003-02-28T23:59:59.000Z
For hydrodynamic model atmospheres, absolute lineshifts are becoming an observable diagnostic tool beyond the classical ones of line-strength, -width, -shape, and -asymmetry. This is the wavelength displacement of different types of spectral lines away from the positions naively expected from the Doppler shift caused by stellar radial motion. Caused mainly by correlated velocity and brightness patterns in granular convection, such absolute lineshifts could in the past be studied only for the Sun (since the relative Sun-Earth motion, and the ensuing Doppler shift is known). For other stars, this is now becoming possible thanks to three separate developments: (a) Astrometric determination of stellar radial motion; (b) High-resolution spectrometers with accurate wavelength calibration, and (c) Accurate laboratory wavelengths for several atomic species. Absolute lineshifts offer a tool to segregate various 2- and 3-dimensional models, and to identify non-LTE effects in line formation.
Absolute Lineshifts - A new diagnostic for stellar hydrodynamics
Dravins, D
2003-01-01T23:59:59.000Z
For hydrodynamic model atmospheres, absolute lineshifts are becoming an observable diagnostic tool beyond the classical ones of line-strength, -width, -shape, and -asymmetry. This is the wavelength displacement of different types of spectral lines away from the positions naively expected from the Doppler shift caused by stellar radial motion. Caused mainly by correlated velocity and brightness patterns in granular convection, such absolute lineshifts could in the past be studied only for the Sun (since the relative Sun-Earth motion, and the ensuing Doppler shift is known). For other stars, this is now becoming possible thanks to three separate developments: (a) Astrometric determination of stellar radial motion; (b) High-resolution spectrometers with accurate wavelength calibration, and (c) Accurate laboratory wavelengths for several atomic species. Absolute lineshifts offer a tool to segregate various 2- and 3-dimensional models, and to identify non-LTE effects in line formation.
Hydrodynamic transport coefficients in relativistic scalar field theory
Jeon, S. [Department of Physics FM-15, University of Washington, Seattle, Washington 98195 (United States)] [Department of Physics FM-15, University of Washington, Seattle, Washington 98195 (United States)
1995-09-15T23:59:59.000Z
Hydrodynamic transport coefficients may be evaluated from first principals in a weakly coupled scalar field theory at an arbitrary temperature. In a theory with cubic and quartic interactions, the infinite class of diagrams which contributes to the leading weak coupling behavior is identified and summed. The resulting expression may be reduced to a single linear integral equation, which is shown to be identical to the corresponding result obtained from a linearized Boltzmann equation describing effective thermal excitations with temperature-dependent masses and scattering amplitudes. The effective Boltzmann equation is valid even at very high temperature where the thermal lifetime and mean free path are short compared to the Compton wavelength of the fundamental particles. Numerical results for the shear and the bulk viscosities are presented.
Hydrodynamic forces on smooth inclined cylinder in oscillatory flow
Kang, H.G. [Dalian Univ. of Technology (China)
1993-12-31T23:59:59.000Z
The hydrodynamic forces on a smooth inclined circular cylinder exposed to oscillating flow were experimentally investigated at Reynolds number (Re) in the range 40,000--200,000 and Keulegan-Capenter number (Kc) in the interval from 5--40. In the test, Re number and Kc number were varied systematically. The inertia force coefficient (C{sub M}) and the drag force coefficient (C{sub D}) in Morison equation were determined form the measured loads and the water particle kinematics. This analysis uses a modified form of Morison equation since it uses the normal velocity and acceleration. Thus, the applicability of the Cross Flow Principle was assumed. This principle, simply stated, is as follows: the force acting in the direction normal to the axis of a cylinder placed at some oblique angle to the direction of flow is expressed in terms of the normal component of flow only, and the axial component is disregarded. Both total in-line force coefficient (C{sub F}) and transverse force (lift) coefficient (C{sub L}) were analyzed in terms of their maximum and root mean square values. All the in-line and lift force coefficient were given as a functions of Re and Kc number. From this research, it can be seen that the Cross-Flow Principle does not always work well. It seems valid for the total in-line force at high Re and large Kc number; the C{sub M} for {alpha} = 45{degree} is larger and the C{sub D} for {alpha} = 45{degree} is smaller than that for {alpha} = 90{degree} and Re {ge} 80,000. The hydrodynamic force coefficients C{sub D} and C{sub M} for the inclined cylinder are only the functions of oblique angle ({alpha}) and Kc number, but not of the Re number.
Impact of hydrodynamics on coal liquefaction. Final technical report
Kang, D.; Ying, D.H.S.; Givens, E.N.
1983-09-01T23:59:59.000Z
We have attempted to determine the hydrodynamic effects of various reactor configurations on coal liquefaction, to help select the optimal reactor configuration and to provide additional understanding of coal liquefaction reaction kinetics, which cannot be definitively determined by a CSTR alone. Only a qualitative understanding of the fluid dynamic effects on product yields has been perceived by operating various sizes of open-column tubular reactors, because the fluid-dynamic characteristics of these reactors were not clearly understood and could not be varied significantly. Indirect studies, by cold-flow simulation, have been of little help in defining the fluid dynamic impact on coal liquefaction. Comparison of actual coal liquefaction data from both the plug-flow reactor and the CSTR showed that the plug-flow configuration had various advantages. Reactor yields improved significantly, especially the primary product conversions. At 840/sup 0/F and residence times of 29 and 40 min, coal and preasphaltene conversions were enhanced approximately 6 and 10%, respectively. At these conditions, the plug-flow reactor also yielded about 10% more oils than the CSTR with significant increase in hydrogen utilization. Also, this study provided an opportunity to examine the soundness of APCI/ICRC's sequential kinetic model, by interfacing the plug-flow and CSTR yield data. Transforming CSTR yields to plug-flow data showed that product yields deviated considerably from the measured plug-flow data, suggesting the need to improve the existing reaction model. Having both CSTR and plug-flow reactor data bases is important for developing a sound coal reaction model and for determining hydrodynamic effects on coal liquefaction in a direct way. The results will lead to an optimized reactor configuration as well as optimized operation. 5 references, 23 figures, 20 tables.
Albanese, Claudio
A Numerical Method for Pricing Electricity Derivatives for Jump-Diffusion Processes Based.tompaidis@mccombs.utexas.edu Corresponding author. Tel. 512-4715252, Fax 512-4710587. #12;A Numerical Method for Pricing Electricity method for pricing derivatives on electricity prices. The method is based on approximating the generator
Wolpert, Robert L
Bayesian analysis of GARCH and stochastic volatility: modeling leverage, jumps and heavy for two broad major classes of varying volatility model, GARCH and stochastic volatility (SV) models-t errors yields the best performance among the competing models on the return data. Key words: GARCH, Heavy
Hydraulic jumps on an incline J E A N L U C T H I F F E A U L T1,2
1 Hydraulic jumps on an incline J E A N L U C T H I F F E A U L T1,2 AND A N D R E W B E L M O N rim resembling a parabola and reminiscent of a hydraulic jump. There appears to be little theory, and present a simple theory based on horizontal hydraulic jumps which accounts for the rise height and its
Universal formulae for thermoelectric transport with magnetic field and disorder
Andrea Amoretti; Daniele Musso
2015-02-09T23:59:59.000Z
We obtain explicit expressions for the thermoelectric transport coefficients of a strongly coupled, planar medium in the presence of an orthogonal magnetic field and disorder. The computations are performed within the gauge/gravity framework, however we propose and argue for a possible universal relevance of the results relying on comparisons and extensions of previous hydrodynamical analyses and experimental data.
Universal formulae for thermoelectric transport with magnetic field and disorder
Amoretti, Andrea
2015-01-01T23:59:59.000Z
We obtain explicit expressions for the thermoelectric transport coefficients of a strongly coupled, planar medium in the presence of an orthogonal magnetic field and disorder. The computations are performed within the gauge/gravity framework, however we propose and argue for a possible universal relevance of the results relying on comparisons and extensions of previous hydrodynamical analyses and experimental data.
On the origin of solar wind. Alfven waves induced jump of coronal temperature
T. M. Mishonov; M. V. Stoev; Y. G. Maneva
2007-06-06T23:59:59.000Z
Absorbtion of Alfven waves is considered to be the main mechanism of heating in the solar corona. It is concluded that the sharp increase of the plasma temperature by two orders of magnitude is related to a self-induced opacity with respect to Alfven waves. The maximal frequency for propagation of Alfven waves is determined by the strongly temperature dependent kinematic viscosity. In such a way the temperature jump is due to absorption of high frequency Alfven waves in a narrow layer above the solar surface. It is calculated that the power per unit area dissipated in this layer due to damping of Alfven waves blows up the plasma and gives birth to the solar wind. A model short wave-length (WKB) evaluation takes into account the 1/f^2 frequency dependance of the transversal magnetic field and velocity spectral densities. Such spectral densities agree with old magnetometric data taken by Voyager 1 and recent theoretical calculations in the framework of Langevin-Burgers MHD. The present theory predicts existence of intensive high frequency MHD Alfven waves in the cold layer beneath the corona. It is briefly discussed how this statement can be checked experimentally. It is demonstrated that the magnitude of the Alfven waves generating random noise and the solar wind velocity can be expressed only in terms of satellite experimental data. It is advocated that investigation of properties of the solar surface as a random driver by optical methods is an important task for future solar physics. Jets of accretion disks are speculated as a special case of the wind from magnetized turbulent plasma.
Non-Relativistic Parity-Violating Hydrodynamics in Two Spatial Dimensions
Matthias Kaminski; Sergej Moroz
2014-04-01T23:59:59.000Z
We construct the non-relativistic parity-violating hydrodynamic description of a two-dimensional dissipative, normal fluid in presence of small U(1) background fields and vorticity. This is achieved by taking the non-relativistic limit of the recently developed relativistic hydrodynamics in 2+1 dimensions. We identify and interpret the resulting parity-violating contributions to the non-relativistic constitutive relations, which include the Hall current flowing perpendicular to the temperature gradient, the Hall viscosity and the Leduc-Righi energy current. Also a comparison of our findings is made with the non-relativistic parity-violating hydrodynamics obtained from a light-cone dimensional reduction.
Effect of Second-Order Hydrodynamics on a Floating Offshore Wind Turbine
Roald, L.; Jonkman, J.; Robertson, A.
2014-05-01T23:59:59.000Z
The design of offshore floating wind turbines uses design codes that can simulate the entire coupled system behavior. At the present, most codes include only first-order hydrodynamics, which induce forces and motions varying with the same frequency as the incident waves. Effects due to second- and higher-order hydrodynamics are often ignored in the offshore industry, because the forces induced typically are smaller than the first-order forces. In this report, first- and second-order hydrodynamic analysis used in the offshore oil and gas industry is applied to two different wind turbine concepts--a spar and a tension leg platform.
Introduction and guide to LLNL's relativistic 3-D nuclear hydrodynamics code
Zingman, J.A.; McAbee, T.L.; Alonso, C.T.; Wilson, J.R.
1987-11-01T23:59:59.000Z
We have constructed a relativistic hydrodynamic model to investigate Bevalac and higher energy, heavy-ion collisions. The basis of the model is a finite-difference solution to covariant hydrodynamics, which will be described in the rest of this paper. This paper also contains: a brief review of the equations and numerical methods we have employed in the solution to the hydrodynamic equations, a detailed description of several of the most important subroutines, and a numerical test on the code. 30 refs., 8 figs., 1 tab.
Bush, John W.M.
2006-01-01T23:59:59.000Z
J. Fluid Mech. (2006), vol. 558, pp. 3352. c 2006 Cambridge University Press doi:10.1017/S hydraulic jump By JOHN W. M. BUS H1 , JEFFREY M. ARISTOFF1 AND A. E. HOSOI2 1 Department of Mathematics; Nonlinearity, vol. 12, 1999, p. 1) demonstrated that the axial symmetry of the circular hydraulic jump may
Hogg, Andrew
2009-01-01T23:59:59.000Z
J. Fluid Mech. (2009), vol. 633, pp. 285309. c 2009 Cambridge University Press doi:10.1017/S conservation of mass and momentum across the shock and thus we show how the hydraulic jump moves within waves form, leading to hydraulic jumps, which translate throughout the domain. Such motions were
Balmforth, Neil
2012-01-01T23:59:59.000Z
J. Fluid Mech. (2012), vol. 695, pp. 3562. c Cambridge University Press 2012 35 doi:10.1017/jfm hydraulic jumps just downstream of the steepest part of the steps. Near onset, steadily migrating, nonlinear. Vakil z x Cyclic step Erodible bed Water Hydraulic jump u(x,t) h(x,t) FIGURE 1. Sketch of the geometry
Blanchette, Robert A.
Species of Mycosphaerellaceae and Teratosphaeriaceae on native Myrtaceae in Uruguay: evidence Proteccion Vegetal, Facultad de Agronomia, Universidad de la Republica, Uruguay b Forestry and Agricultural Agropecuaria (INIA), Uruguay d Department of Plant Pathology, University of Minnesota, USA a r t i c l e i n f
Matha, D.; Schlipf, M.; Cordle, A.; Pereira, R.; Jonkman, J.
2011-10-01T23:59:59.000Z
This paper presents the current major modeling challenges for floating offshore wind turbine design tools and describes aerodynamic and hydrodynamic effects due to rotor and platform motions and usage of non-slender support structures.
Design of the All-Electric Ship: Focus on Integrated Power System Coupled to Hydrodynamics
Prempraneerach, P.
2008-01-01T23:59:59.000Z
We present a detailed model of the integrated power system coupled to hydrodynamics that allows us to study global sensitivities in the All-Electric Ship. A novel element of our formulation is the stochastic modeling of ...
A model for analyzing the effects of hydrodynamic forces on cell adhesion in a perfused bioreactor
Owens, Bryan D
2007-01-01T23:59:59.000Z
In bioreactor culture systems that aim to provide a convective flux to address mass transport limitations of oxygen and other nutrients, large hydrodynamic forces and shear stress can potentially serve as a negative signals ...
Simulation and Optimization of DPP Hydrodynamics and Radiation Transport for EUV Lithography Devices
Harilal, S. S.
be used to study the hydrodynamics and radiation in two-gas mixtures of dense plasma focus (DPF) and z the HEIGHTS- EUV package are schematically shown in Figure 1: a) A dense plasma focus device, b) A hollow
Scattering and nonlinear bound states of hydrodynamically coupled particles in a narrow channel
Doyle, Patrick S.
We model a pair of hydrodynamically interacting particles confined in a channel with thin rectangular cross section. We find that the particles have a finite region of attraction, which arises from the screening of dipolar ...
Mendelson, Leah Rose
2013-01-01T23:59:59.000Z
Abstract This thesis details the implementation of a three-dimensional PIV system to study the hydrodynamics of freely swimming Giant Danio (Danio aequipinnatus). Volumetric particle fields are reconstructed using synthetic ...
The role of hydrodynamic interactions in the dynamics and viscoelasticity of actin networks
Karimi, Reza, Ph. D. Massachusetts Institute of Technology
2012-01-01T23:59:59.000Z
Actin, the primary component of the cytoskeleton, is the most studied semi-flexible filament, yet its dynamics remains elusive. We show that hydrodynamic interactions (HIs) significantly alter the time scale of actin ...
Measurements of static loading characteristics of a Flexurepivot Tilt Pad Hydrodynamic Bearing
Walton, Nicholas Van Edward
1995-01-01T23:59:59.000Z
An experimental investigation examining the static loading characteristics of a four-pad, KMC FLEXUREPIVOT Tilt Pad Hydrodynamic Bearing is presented. Tests are conducted on the TRACE Fluid Film Bearing Element Test Rig for journal speeds ranging...
CFD study of hydrodynamic signal perception by fish using the lateral line system
Rapo, Mark Andrew
2009-01-01T23:59:59.000Z
The lateral line system on fish has been found to aid in schooling behavior, courtship communication, active and passive hydrodynamic imaging, and prey detection. The most widely used artificial prey stimulus has been the ...
A Smoothed Particle Hydrodynamics-Based Fluid Model With a Spatially...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
A Smoothed Particle Hydrodynamics-Based Fluid Model With a Spatially Dependent Viscosity Authors: Martys, N.S., George, W.L., Chun, B., Lootens, D. A smoothed particle...
Laverty, Stephen Michael
2005-01-01T23:59:59.000Z
This thesis looks at the hydrodynamics of spherical projectiles impacting the free surface using a unique experimental WebLab facility. Experiments were performed to determine the force impact coefficients of spheres and ...
A Model for the Dynamic User-Equilibrium Problem Using a Hydrodynamic Theory Approach
Perakis, Georgia
In this paper we study the dynamic user-equilibrium problem. The development of Intelligent Vehicle Highway Systems (IVHS) has made this problem very popular in the recent years. In this paper we take a hydrodynamic theory ...
The hydrodynamic stability of crossflow vortices in the Bdewadt boundary layer
The hydrodynamic stability of crossflow vortices in the Bödewadt boundary layer N. A. Culverhouse the critical Reynolds number. extends the laminar flow region. decreasing the magnitude of the crossflow
Hydrodynamics and heat transfer during flow boiling instabilities in a single microchannel
Aussillous, Pascale
Hydrodynamics and heat transfer during flow boiling instabilities in a single microchannel July 2008 Keywords: Boiling Microchannels Visualisation Flow boiling instabilities Heat transfer a b intensification heat removal. Flow boiling heat transfer in microchannel geometry and the associated flow
Energy Conversion Efficiency of Nanofluidic Batteries: Hydrodynamic Slip and Access Resistance
Chang, Hsueh-Chia
Energy Conversion Efficiency of Nanofluidic Batteries: Hydrodynamic Slip and Access Resistance Yu channels. INTRODUCTION Nanofluidic batteries are interesting energy generation systems for converting with this nanofluidic battery system has gained considerable attention. One of the challenges for the nanofluidic
Physico-chemical hydrodynamics of droplets on textured surfaces with engineered micro/nanostructures
Park, Kyoo Chul
2013-01-01T23:59:59.000Z
Understanding physico-chemical hydrodynamics of droplets on textured surfaces is of fundamental and practical significance for designing a diverse range of engineered surfaces such as low-reflective, self-cleaning or ...
IUTAM symposium on hydrodynamic diffusion of suspended particles
Davis, R.H. [ed.
1995-12-31T23:59:59.000Z
Hydrodynamic diffusion refers to the fluctuating motion of nonBrownian particles (or droplets or bubbles) which occurs in a dispersion due to multiparticle interactions. For example, in a concentrated sheared suspension, particles do not move along streamlines but instead exhibit fluctuating motions as they tumble around each other. This leads to a net migration of particles down gradients in particle concentration and in shear rate, due to the higher frequency of encounters of a test particle with other particles on the side of the test particle which has higher concentration or shear rate. As another example, suspended particles subject to sedimentation, centrifugation, or fluidization, do not generally move relative to the fluid with a constant velocity, but instead experience diffusion-like fluctuations in velocity due to interactions with neighboring particles and the resulting variation in the microstructure or configuration of the suspended particles. In flowing granular materials, the particles interact through direct collisions or contacts (rather than through the surrounding fluid); these collisions also cause the particles to undergo fluctuating motions characteristic of diffusion processes. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database.
Low Mach Number Fluctuating Hydrodynamics of Diffusively Mixing Fluids
A. Donev; A. J. Nonaka; Y. Sun; T. G. Fai; A. L. Garcia; J. B. Bell
2014-04-29T23:59:59.000Z
We formulate low Mach number fluctuating hydrodynamic equations appropriate for modeling diffusive mixing in isothermal mixtures of fluids with different density and transport coefficients. These equations eliminate the fluctuations in pressure associated with the propagation of sound waves by replacing the equation of state with a local thermodynamic constraint. We demonstrate that the low Mach number model preserves the spatio-temporal spectrum of the slower diffusive fluctuations. We develop a strictly conservative finite-volume spatial discretization of the low Mach number fluctuating equations in both two and three dimensions and construct several explicit Runge-Kutta temporal integrators that strictly maintain the equation of state constraint. The resulting spatio-temporal discretization is second-order accurate deterministically and maintains fluctuation-dissipation balance in the linearized stochastic equations. We apply our algorithms to model the development of giant concentration fluctuations in the presence of concentration gradients, and investigate the validity of common simplifications such as neglecting the spatial non-homogeneity of density and transport properties. We perform simulations of diffusive mixing of two fluids of different densities in two dimensions and compare the results of low Mach number continuum simulations to hard-disk molecular dynamics simulations. Excellent agreement is observed between the particle and continuum simulations of giant fluctuations during time-dependent diffusive mixing.
Simulating Magnetized Laboratory Plasmas with Smoothed Particle Hydrodynamics
Johnson, J N
2009-07-02T23:59:59.000Z
The creation of plasmas in the laboratory continues to generate excitement in the physics community. Despite the best efforts of the intrepid plasma diagnostics community, the dynamics of these plasmas remains a difficult challenge to both the theorist and the experimentalist. This dissertation describes the simulation of strongly magnetized laboratory plasmas with Smoothed Particle Hydrodynamics (SPH), a method born of astrophysics but gaining broad support in the engineering community. We describe the mathematical formulation that best characterizes a strongly magnetized plasma under our circumstances of interest, and we review the SPH method and its application to astrophysical plasmas based on research by Phillips [1], Buerve [2], and Price and Monaghan [3]. Some modifications and extensions to this method are necessary to simulate terrestrial plasmas, such as a treatment of magnetic diffusion based on work by Brookshaw [4] and by Atluri [5]; we describe these changes as we turn our attention toward laboratory experiments. Test problems that verify the method are provided throughout the discussion. Finally, we apply our method to the compression of a magnetized plasma performed by the Compact Toroid Injection eXperiment (CTIX) [6] and show that the experimental results support our computed predictions.
Cosmological Simulations of Galaxy Formation Including Hydrodynamics (hyper-abridged)
F J Summers
1994-06-02T23:59:59.000Z
The formation of galaxies in hierarchical cosmogonies is studied using high resolution N-body plus SPH hydrodynamics simulations. The collapse of structure is followed self-consistently from Mpc scale filamentary structures to kpc scale galactic objects. The characteristics and formation processes of the galaxy like objects are studied in detail, along with the aggregation into a poor cluster. Related studies consider the effects of modelling star formation, the reliability of tracing galaxies in simulations, and tests of SPH methods. This submission serves first to notify that the full text and figures of my thesis are available in compressed PostScript form via anonymous ftp from astro.princeton.edu in the directory /summers/thesis (122 files, 19 MB compressed, 65 MB uncompressed). See the README file first. Second, this submission contains the title page, abstract, table of contents, introductory chapter, summary chapter, and references for my thesis. Those who are curious about the work may scan these pages to identify which chapters may be interesting to get via ftp.
Design of an electromagnetic accelerator for turbulent hydrodynamic mix studies
Susoeff, A.R.; Hawke, R.S.; Morrison, J.J.; Dimonte, G.; Remington, B.A.
1993-12-08T23:59:59.000Z
An electromagnetic accelerator in the form of a linear electric motor (LEM) has been designed to achieve controlled acceleration profiles of a carriage containing hydrodynamically unstable fluids for the investigation of the development of turbulent mix. The Rayleigh- Taylor instability is investigated by accelerating two dissimilar density fluids using the LEM to achieve a wide variety of acceleration and deceleration profiles. The acceleration profiles are achieved by independent control of rail and augmentation currents. A variety of acceleration-time profiles are possible including: (1) constant, (2) impulsive and (3) shaped. The LEM and support structure are a robust design in order to withstand high loads with deflections and to mitigate operational vibration. Vibration of the carriage during acceleration could create artifacts in the data which would interfere with the intended study of the Rayleigh-Taylor instability. The design allows clear access for diagnostic techniques such as laser induced fluorescence radiography, shadowgraphs and particle imaging velocimetry. Electromagnetic modeling codes were used to optimize the rail and augmentation coil positions within the support structure framework. Results of contemporary studies for non-arcing sliding contact of solid armatures are used for the design of the driving armature and the dynamic electromagnetic braking system. A 0. 6MJ electrolytic capacitor bank is used for energy storage to drive the LEM. This report will discuss a LEM design which will accelerate masses of up to 3kg to a maximum of about 3000g{sub o}, where g{sub o} is accelerated due to gravity.
MODEST: modeling stellar evolution and (hydro)dynamics
Piet Hut
2003-09-15T23:59:59.000Z
Simulations of dense stellar systems currently face two major hurdles, one astrophysical and one computational. The astrophysical problem lies in the fact that several major stages in binary evolution, such as common envelope evolution, are still poorly understood. The best we can do in these cases is to parametrize our ignorance, in a way that is reminiscent of the introduction of a mixing length to describe convection in a single star, or an alpha parameter in modeling an accretion disk. The hope is that by modeling a whole star cluster in great detail, and comparing the results to the wealth of observational data currently available, we will be able to constrain the parameters that capture the unknown physics. The computational problem is one of composition: while we have accurate computer codes for modeling stellar dynamics, stellar hydrodynamics, and stellar evolution, we currently have no good way to put all this knowledge together in a single software environment. A year ago, a loosely-knit organization was founded to address these problems, MODEST for MOdeling DEnse STellar systems, with nine working groups and a series of meetings that are held every half year. This report reviews the first year of this initiative. Much more detail can be found on the MODEST web site http://www.manybody.org/modest.html .
Driven cavity flow: from molecular dynamics to continuum hydrodynamics
Tiezheng Qian; Xiao-Ping Wang
2004-03-06T23:59:59.000Z
Molecular dynamics (MD) simulations have been carried out to investigate the slip of fluid in the lid driven cavity flow where the no-slip boundary condition causes unphysical stress divergence. The MD results not only show the existence of fluid slip but also verify the validity of the Navier slip boundary condition. To better understand the fluid slip in this problem, a continuum hydrodynamic model has been formulated based upon the MD verification of the Navier boundary condition and the Newtonian stress. Our model has no adjustable parameter because all the material parameters (density, viscosity, and slip length) are directly determined from MD simulations. Steady-state velocity fields from continuum calculations are in quantitative agreement with those from MD simulations, from the molecular-scale structure to the global flow. The main discovery is as follows. In the immediate vicinity of the corners where moving and fixed solid surfaces intersect, there is a core partial-slip region where the slippage is large at the moving solid surface and decays away from the intersection quickly. In particular, the structure of this core region is nearly independent of the system size. On the other hand, for sufficiently large system, an additional partial-slip region appears where the slippage varies as $1/r$ with $r$ denoting the distance from the corner along the moving solid surface. The existence of this wide power-law region is in accordance with the asymptotic $1/r$ variation of stress and the Navier boundary condition.
Onset and cessation of motion in hydrodynamically sheared granular beds
Abram H. Clark; Mark D. Shattuck; Nicholas T. Ouellette; Corey S. O'Hern
2015-04-14T23:59:59.000Z
To clarify the grain-scale mechanisms that control the onset and cessation of sediment transport, we performed molecular dynamics simulations of granular beds driven by a model hydrodynamic shear flow. We find a critical value for the Shields number (the nondimensional shear stress at the top of the granular bed) that separates flowing and static states, with a bed flow rate that is discontinuous at the critical value. The transition times between flowing and static states diverge as the system approaches the critical Shields number from above and below. Additionally we find that, for finite systems, the onset of flow occurs stochastically at supercritical Shields numbers. We show that the statistics of the Shields number at failure obey Weibullian weakest-link statistics, and that the onset of flow is caused by local grain rearrangements that give rise to additional rearrangements and then to continuous flow. Thus, the onset of motion is governed by the packing structure of the granular bed, even deep beneath the surface. Since the fluid dynamics is strongly coupled to the settling process and thus to the bed structure, this also suggests a strong feedback between the fluid dynamics and granular physics in bed mobilization.
Hybrid magneto-hydrodynamic simulation of a driven FRC
Rahman, H. U., E-mail: hrahman@trialphaenergy.com; Wessel, F. J.; Binderbauer, M. W.; Qerushi, A.; Rostoker, N. [Tri Alpha Energy, Inc., P.O. Box 7010, Rancho Santa Margarita, California 92688 (United States)] [Tri Alpha Energy, Inc., P.O. Box 7010, Rancho Santa Margarita, California 92688 (United States); Conti, F. [Physics Department “E. Fermi,” University of Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy) [Physics Department “E. Fermi,” University of Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Plasma Diagnostics and Technologies Ltd., Via Giuntini 63, 56023 Navacchio (PI) (Italy); Ney, P. [Mount San Jacinto College, Menifee, California 92584 (United States)] [Mount San Jacinto College, Menifee, California 92584 (United States)
2014-03-15T23:59:59.000Z
We simulate a field-reversed configuration (FRC), produced by an “inductively driven” FRC experiment; comprised of a central-flux coil and exterior-limiter coil. To account for the plasma kinetic behavior, a standard 2-dimensional magneto-hydrodynamic code is modified to preserve the azimuthal, two-fluid behavior. Simulations are run for the FRC's full-time history, sufficient to include: acceleration, formation, current neutralization, compression, and decay. At start-up, a net ion current develops that modifies the applied-magnetic field forming closed-field lines and a region of null-magnetic field (i.e., a FRC). After closed-field lines form, ion-electron drag increases the electron current, canceling a portion of the ion current. The equilibrium is lost as the total current eventually dissipates. The time evolution and magnitudes of the computed current, ion-rotation velocity, and plasma temperature agree with the experiments, as do the rigid-rotor-like, radial-profiles for the density and axial-magnetic field [cf. Conti et al. Phys. Plasmas 21, 022511 (2014)].
Hydrodynamical Simulations of Nuclear Rings in Barred Galaxies
Li, Zhi; Kim, Woong-Tae
2015-01-01T23:59:59.000Z
Dust lanes, nuclear rings, and nuclear spirals are typical gas structures in the inner region of barred galaxies Their shapes and properties are linked to the physical parameters of the host galaxy. We use high-resolution hydrodynamical simulations to study 2D gas flows in simple barred galaxy models. The nuclear rings formed in our simulations can be divided into two groups: one group is nearly round and the other is highly elongated. We find that roundish rings may not form when the bar pattern speed is too high or the bulge central density is too low. We also study the periodic orbits in our galaxy models, and find that the concept of inner Lindblad resonance (ILR) may be generalized by the extent of $x_2$ orbits. All roundish nuclear rings in our simulations settle in the range of $x_2$ orbits (or ILRs). However, knowing the resonances is insufficient to pin down the exact location of these nuclear rings. We suggest that the backbone of round nuclear rings is the $x_2$ orbital family, i.e. round nuclear r...
Hydrodynamical model for $J/?$ suppression and elliptic flow
A. K. Chaudhuri
2009-10-06T23:59:59.000Z
In a hydrodynamic model, we have studied $J/\\psi$ suppression and elliptic flow in Au+Au collisions at RHIC energy $\\sqrt{s}$=200 GeV. At the initial time, $J/\\psi$'s are randomly distributed in the fluid. As the fluid evolve in time, the free streaming $J/\\psi$'s are dissolved if the local fluid temperature exceeds a melting temperature $T_{J/\\psi}$. Sequential melting of charmonium states ($\\chi_c$, $\\psi\\prime$ and $J/\\psi$), with melting temperatures $T_{\\chi_c}=T_{\\psi\\prime} \\approx 1.2T_c$, $T_{J/\\psi} \\approx2T_c$ and feed-down fraction $F\\approx 0.3$, is consistent with the PHENIX data on $J/\\psi$ suppression and near zero elliptic flow for $J/\\psi$'s. It is also shown that the model will require substantial regeneration of charmoniums, if the charmonium states dissolve at temperature close to the critical temperature, $T_{\\chi_c}=T_{\\psi\\prime} \\leq T_c$, $T_{J/\\psi}\\approx1.2T_c$. The regenerated charmoniums will have positive elliptic flow.
The chemical enrichment of the ICM from hydrodynamical simulations
S. Borgani; D. Fabjan; L. Tornatore; S. Schindler; K. Dolag; A. Diaferio
2008-01-07T23:59:59.000Z
The study of the metal enrichment of the intra-cluster and inter-galactic media (ICM and IGM) represents a direct means to reconstruct the past history of star formation, the role of feedback processes and the gas-dynamical processes which determine the evolution of the cosmic baryons. In this paper we review the approaches that have been followed so far to model the enrichment of the ICM in a cosmological context. While our presentation will be focused on the role played by hydrodynamical simulations, we will also discuss other approaches based on semi-analytical models of galaxy formation, also critically discussing pros and cons of the different methods. We will first review the concept of the model of chemical evolution to be implemented in any chemo-dynamical description. We will emphasise how the predictions of this model critically depend on the choice of the stellar initial mass function, on the stellar life-times and on the stellar yields. We will then overview the comparisons presented so far between X-ray observations of the ICM enrichment and model predictions. We will show how the most recent chemo-dynamical models are able to capture the basic features of the observed metal content of the ICM and its evolution. We will conclude by highlighting the open questions in this study and the direction of improvements for cosmological chemo-dynamical models of the next generation.
Kohn, Gabriel (Omer, IL); Hicho, George (Derwood, MD); Swartzendruber, Lydon (New Carrollton, MD)
1997-01-01T23:59:59.000Z
A steel hardness measurement system and method of using same are provided for measuring at least one mechanical or magnetic characteristic of a ferromagnetic sample as a function of at least one magnetic characteristic of the sample. A magnetic field generator subjects the sample to a variable external magnetic field. The magnetic field intensity of the magnetic field generated by the magnetic field generating means is measured and a signal sensor is provided for measuring Barkhausen signals from the sample when the sample is subjected to the external magnetic field. A signal processing unit calculates a jump sum rate first moment as a function of the Barkhausen signals measured by the signal sensor and the magnetic field intensity, and for determining the at least one mechanical or magnetic characteristic as a function of the jump sum rate first moment.
Kohn, G.; Hicho, G.; Swartzendruber, L.
1997-04-08T23:59:59.000Z
A steel hardness measurement system and method of using same are provided for measuring at least one mechanical or magnetic characteristic of a ferromagnetic sample as a function of at least one magnetic characteristic of the sample. A magnetic field generator subjects the sample to a variable external magnetic field. The magnetic field intensity of the magnetic field generated by the magnetic field generating means is measured and a signal sensor is provided for measuring Barkhausen signals from the sample when the sample is subjected to the external magnetic field. A signal processing unit calculates a jump sum rate first moment as a function of the Barkhausen signals measured by the signal sensor and the magnetic field intensity, and for determining the at least one mechanical or magnetic characteristic as a function of the jump sum rate first moment. 7 figs.
Hydrodynamic flow in Lower Cretaceous Muddy Sandstones, Rozet Field, Powder River Basin, Wyoming
Smith, David Arthur
1984-01-01T23:59:59.000Z
/km) across the field yields a hydrodynamic oil column of 420 ft (128 m). Capillary pressure differences due to permeability changes account for a oil column of 72 ft (42 m). The combined capillary and hydrodynamic oil columns of 492 ft (150 m) compares... and other Muddy Formation oil fields. Contour interval 1000 ft (305 m). . . Regional east-west cross section showing variable sandstone development in the Muddy interval from Kitty to Rozet Fields. . . . . . . . . Diagrammatic environments the northern...
Hydrodynamics of the Mission Canyon Formation in the Billings Nose area, North Dakota
Mitsdarffer, Alan Ray
1985-01-01T23:59:59.000Z
and associated highlands of central Montana (Fish and Kinard, 1959). Hydrodynamic flow was considered as a possible cause for the observed tilted oil-water contact for the Nottingham field in Saskatchewan, but the direction of tilt was opposite to flow... conditions with low gradients similiar to that depicted by the regional map. The present hydrodynamic conditions result from the recent invasion of the field area by the fresher ~ster lens. The oil accumulation will eventually be flushed from the area...
Dynamic Forces between Bubbles and Surfaces and Hydrodynamic Boundary Conditions
Chan, Derek Y C
of Mathematics, National UniVersity of Singapore, 117543 Singapore, Institute of High Performance Computing, 1 of High Performance Computing. | Institute of Chemical and Engineering Sciences. (1) Whitesides, G. M
C. Noel; Y. Busegnies; M. V. Papalexandris; V. Deledicque; A. El Messoudi
2007-05-18T23:59:59.000Z
Aims. This work presents a new hydrodynamical algorithm to study astrophysical detonations. A prime motivation of this development is the description of a carbon detonation in conditions relevant to superbursts, which are thought to result from the propagation of a detonation front around the surface of a neutron star in the carbon layer underlying the atmosphere. Methods. The algorithm we have developed is a finite-volume method inspired by the original MUSCL scheme of van Leer (1979). The algorithm is of second-order in the smooth part of the flow and avoids dimensional splitting. It is applied to some test cases, and the time-dependent results are compared to the corresponding steady state solution. Results. Our algorithm proves to be robust to test cases, and is considered to be reliably applicable to astrophysical detonations. The preliminary one-dimensional calculations we have performed demonstrate that the carbon detonation at the surface of a neutron star is a multiscale phenomenon. The length scale of liberation of energy is $10^6$ times smaller than the total reaction length. We show that a multi-resolution approach can be used to solve all the reaction lengths. This result will be very useful in future multi-dimensional simulations. We present also thermodynamical and composition profiles after the passage of a detonation in a pure carbon or mixed carbon-iron layer, in thermodynamical conditions relevant to superbursts in pure helium accretor systems.
Density Power Spectrum of Compressible Hydrodynamic Turbulent Flows
Jongsoo Kim; Dongsu Ryu
2005-07-26T23:59:59.000Z
Turbulent flows are ubiquitous in astrophysical environments, and understanding density structures and their statistics in turbulent media is of great importance in astrophysics. In this paper, we study the density power spectra, $P_{\\rho}$, of transonic and supersonic turbulent flows through one and three-dimensional simulations of driven, isothermal hydrodynamic turbulence with root-mean-square Mach number in the range of $1 \\la M_{\\rm rms} \\la 10$. From one-dimensional experiments we find that the slope of the density power spectra becomes gradually shallower as the rms Mach number increases. It is because the density distribution transforms from the profile with {\\it discontinuities} having $P_{\\rho} \\propto k^{-2}$ for $M_{\\rm rms} \\sim 1$ to the profile with {\\it peaks} having $P_{\\rho} \\propto k^0$ for $M_{\\rm rms} \\gg 1$. We also find that the same trend is carried to three-dimension; that is, the density power spectrum flattens as the Mach number increases. But the density power spectrum of the flow with $M_{\\rm rms} \\sim 1$ has the Kolmogorov slope. The flattening is the consequence of the dominant density structures of {\\it filaments} and {\\it sheets}. Observations have claimed different slopes of density power spectra for electron density and cold H I gas in the interstellar medium. We argue that while the Kolmogorov spectrum for electron density reflects the {\\it transonic} turbulence of $M_{\\rm rms} \\sim 1$ in the warm ionized medium, the shallower spectrum of cold H I gas reflects the {\\it supersonic} turbulence of $M_{\\rm rms} \\sim$ a few in the cold neutral medium.
Preparing for an explosion: Hydrodynamic instabilities and turbulence in presupernovae
Smith, Nathan; Arnett, W. David, E-mail: nathans@as.arizona.edu, E-mail: darnett@as.arizona.edu [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States)
2014-04-20T23:59:59.000Z
Both observations and numerical simulations are discordant with predictions of conventional stellar evolution codes for the latest stages of a massive star's life before core collapse. The most dramatic example of this disconnect is in the eruptive mass loss occurring in the decade preceding Type IIn supernovae. We outline the key empirical evidence that indicates severe pre-supernova instability in massive stars, and we suggest that the chief reason that these outbursts are absent in stellar evolution models may lie in the treatment of turbulent convection in these codes. The mixing length theory that is used ignores (1) finite amplitude fluctuations in velocity and temperature and (2) their nonlinear interaction with nuclear burning. Including these fluctuations is likely to give rise to hydrodynamic instabilities in the latest burning sequences, which prompts us to discuss a number of far-reaching implications for the fates of massive stars. In particular, we explore connections to enhanced pre-supernova mass loss, unsteady nuclear burning and consequent eruptions, swelling of the stellar radius that may trigger violent interactions with a companion star, and potential modifications to the core structure that could dramatically alter calculations of the core-collapse explosion mechanism itself. These modifications may also impact detailed nucleosynthesis and measured isotopic anomalies in meteorites, as well as the interpretation of young core-collapse supernova remnants. Understanding these critical instabilities in the final stages of evolution may make possible the development of an early warning system for impending core collapse, if we can identify their asteroseismological or eruptive signatures.
Effects of Second-Order Hydrodynamics on a Semisubmersible Floating Offshore Wind Turbine: Preprint
Bayati, I.; Jonkman, J.; Robertson, A.; Platt, A.
2014-07-01T23:59:59.000Z
The objective of this paper is to assess the second-order hydrodynamic effects on a semisubmersible floating offshore wind turbine. Second-order hydrodynamics induce loads and motions at the sum- and difference-frequencies of the incident waves. These effects have often been ignored in offshore wind analysis, under the assumption that they are significantly smaller than first-order effects. The sum- and difference-frequency loads can, however, excite eigenfrequencies of the system, leading to large oscillations that strain the mooring system or vibrations that cause fatigue damage to the structure. Observations of supposed second-order responses in wave-tank tests performed by the DeepCwind consortium at the MARIN offshore basin suggest that these effects might be more important than originally expected. These observations inspired interest in investigating how second-order excitation affects floating offshore wind turbines and whether second-order hydrodynamics should be included in offshore wind simulation tools like FAST in the future. In this work, the effects of second-order hydrodynamics on a floating semisubmersible offshore wind turbine are investigated. Because FAST is currently unable to account for second-order effects, a method to assess these effects was applied in which linearized properties of the floating wind system derived from FAST (including the 6x6 mass and stiffness matrices) are used by WAMIT to solve the first- and second-order hydrodynamics problems in the frequency domain. The method has been applied to the OC4-DeepCwind semisubmersible platform, supporting the NREL 5-MW baseline wind turbine. The loads and response of the system due to the second-order hydrodynamics are analysed and compared to first-order hydrodynamic loads and induced motions in the frequency domain. Further, the second-order loads and induced response data are compared to the loads and motions induced by aerodynamic loading as solved by FAST.
Bucknell University | Open Energy Information
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Thermodynamic and hydrodynamic behaviour of interacting Fermi gases
Goulko, Olga
2012-01-10T23:59:59.000Z
of the resources provided by the University of Cambridge High Performance Computing Service (http://www.hpc.cam.ac.uk/). I am grateful to Stuart Rankin from the HPC for help on various occasions. 5 Contents Summary 3 Acknowledgements 4 1 Introduction 8 1...
Hydrodynamic sweepout thresholds in BWR Mark III reactor cavity interactions
Spencer, B.W.; Baronowsky, S.P.; Kilsdonk, D.J.
1984-04-01T23:59:59.000Z
Simulant-material experiments and related analysis are described which investigated hydrodynamics aspects of ex-vessel interactions following postulated core meltdown with subsequent meltthrough of the vessel lower head and ejection of molten corium from the vessel into the containment region beneath the vessel. Objectives were to examine the possible sweepout of water and corium from the cavity by the steam/H/sub 2/ flow. The dispersal pathways in this containment design include a single manway and four CRD penetrations in the cylindrical pedestal wall connecting to the drywell with a combined cross-sectional area of approx. 10 m/sup 2/. These openings range from 3.4 to 6.3 m in elevation off the concrete floor of the cavity. The experiments were performed using a 1:34 scale mock-up of the RPV/pedestal region. The first tests were quasi-steady tests. Tests were also performed using molten Wood's metal (WM). Some tests were performed with water on the cavity floor, and one test was performed using steel shot. The test results indicated that threshold gas flowrates existed beyond which dispersal of water and/or corium from the cavity can be expected. The predominant dispersal flow regime observed in the experiments involved fluidization of the water or molten WM by the gas flowrate through the system and sweepout of the fluidized liquid droplets as the gas exited the cavity through the openings in the wall. The superficial gas velocity at the onset of water sweepout ranged from 0.87 to 1.04 m/s in the tests which agrees very closely to the calculated fluidization threshold of 0.96 m/s. Application of the fluidization model for prediction of sweepout for the full-size system suggests that sweepout of water and corium can occur if the breach size in the RPV lower head exceeds approx. 10 and 17 cm dia, respectively, for steam blowdown at a vessel initial pressure of 1000 psi.
Stellar hydrodynamical modeling of dwarf galaxies: simulation methodology, tests, and first results
Vorobyov, Eduard I; Hensler, Gerhard
2015-01-01T23:59:59.000Z
Cosmological simulations still lack numerical resolution or physical processes to simulate dwarf galaxies in sufficient details. Accurate numerical simulations of individual dwarf galaxies are thus still in demand. We aim at (i) studying in detail the coupling between stars and gas in a galaxy, exploiting the so-called stellar hydrodynamical approach, and (ii) studying the chemo-dynamical evolution of individual galaxies starting from self-consistently calculated initial gas distributions. We present a novel chemo-dynamical code in which the dynamics of gas is computed using the usual hydrodynamics equations, while the dynamics of stars is described by the stellar hydrodynamics approach, which solves for the first three moments of the collisionless Boltzmann equation. The feedback from stellar winds and dying stars is followed in detail. In particular, a novel and detailed approach has been developed to trace the aging of various stellar populations, which enables an accurate calculation of the stellar feedba...
Jonkman, J. M.; Sclavounos, P. D.
2006-01-01T23:59:59.000Z
Aeroelastic simulation tools are routinely used to design and analyze onshore wind turbines, in order to obtain cost effective machines that achieve favorable performance while maintaining structural integrity. These tools employ sophisticated models of wind-inflow; aerodynamic, gravitational, and inertial loading of the rotor, nacelle, and tower; elastic effects within and between components; and mechanical actuation and electrical responses of the generator and of control and protection systems. For offshore wind turbines, additional models of the hydrodynamic loading in regular and irregular seas, the dynamic coupling between the support platform motions and wind turbine motions, and the dynamic characterization of mooring systems for compliant floating platforms are also important. Hydrodynamic loading includes contributions from hydrostatics, wave radiation, and wave scattering, including free surface memory effects. The integration of all of these models into comprehensive simulation tools, capable of modeling the fully coupled aeroelastic and hydrodynamic responses of floating offshore wind turbines, is presented.
Asymmetric (1+1)-dimensional hydrodynamics in high-energy collisions
Bialas, A. [H. Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, Radzikowskiego 152, PL-30-059 Krakow, Poland and M. Smoluchowski Institute of Physics, Jagellonian University, Reymonta 4, PL-30-059 Krakow (Poland); Peschanski, R. [Institut de Physique Theorique, CEA-Saclay, F-91191 Gif-sur-Yvette Cedex (France)
2011-05-15T23:59:59.000Z
The possibility that particle production in high-energy collisions is a result of two asymmetric hydrodynamic flows is investigated using the Khalatnikov form of the (1+1)-dimensional approximation of hydrodynamic equations. The general solution is discussed and applied to the physically appealing ''generalized in-out cascade'' where the space-time and energy-momentum rapidities are equal at initial temperature but boost invariance is not imposed. It is demonstrated that the two-bump structure of the entropy density, characteristic of the asymmetric input, changes easily into a single broad maximum compatible with data on particle production in symmetric processes. A possible microscopic QCD interpretation of asymmetric hydrodynamics is proposed.
Edinburgh University aka Wave Power Group | Open Energy Information
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are beingZealand JumpConceptual Model,DOEHazel Crest, Illinois:Edinburgh University aka Wave Power Group Jump to:
Qing Ai; Yuan-Jia Fan; Bih-Yaw Jin; Yuan-Chung Cheng
2014-04-19T23:59:59.000Z
We present a non-Markovian quantum jump approach for simulating coherent energy transfer dynamics in molecular systems in the presence of laser fields. By combining a coherent modified Redfield theory (CMRT) and a non-Markovian quantum jump (NMQJ) method, this new approach inherits the broad-range validity from the CMRT and highly efficient propagation from the NMQJ. To implement NMQJ propagation of CMRT, we show that the CMRT master equation can be casted into a generalized Lindblad form. Moreover, we extend the NMQJ approach to treat time-dependent Hamiltonian, enabling the description of excitonic systems under coherent laser fields. As a benchmark of the validity of this new method, we show that the CMRT-NMQJ method accurately describes the energy transfer dynamics in a prototypical photosynthetic complex. Finally, we apply this new approach to simulate the quantum dynamics of a dimer system coherently excited to coupled single-excitation states under the influence of laser fields, which allows us to investigate the interplay between the photoexcitation process and ultrafast energy transfer dynamics in the system. We demonstrate that laser-field parameters significantly affect coherence dynamics of photoexcitations in excitonic systems, which indicates that the photoexcitation process must be explicitly considered in order to properly describe photon-induced dynamics in photosynthetic systems. This work should provide a valuable tool for efficient simulations of coherent control of energy flow in photosynthetic systems and artificial optoelectronic materials.
Laser-induced temperature jump/time-resolved infrared study of the fast events in protein folding
Woodruff, W.H.; Dyer, R.B.; Williams, S. [Los Alamos National Laboratory, NM (United States); Callender, H.; Gilmanshin, R. [CUNY, NY (United States)
1996-10-01T23:59:59.000Z
Laser-induced temperature jump followed by time-resolved infrared probe of reaction dynamics are used to study the temporal evolution of polypeptide structure during protein folding and unfolding. Reactions are initiated in times of 50 ps or longer by T-jumps of 10`s of degrees, obtained by laser excitation of water overtone absorbances. Observation of the Amide I transient absorbances reveal melting lifetimes of helices unconstrained by tertiary structure to be ca. 160 ns in a model 21-peptide and ca. 30 ns in {open_quotes}molten globule{close_quotes} apomyoglobin. No other processes are observed in these systems over the timescale 50 ps to 2 ms. Equilibrium data suggest the corresponding helix formation lifetimes to be ca. 16 and 1 ns, respectively. In {open_quotes}native{close_quotes} apomyoglobin two helix melting lifetimes are observed and we infer that a third occurs on a timescale inaccessible to our experiment (> 1 ms). The shorter observed lifetime, as in the molten globule, is ca. 30 ns. The longer lifetime is ca. 70 {mu}s. We suggest that the slower process is helix melting that is rate-limited by the unfolding of tertiary structure. Equilibrium data suggest a lifetime of ca. 1 {mu}s for the development of these tertiary folds.
Henriques, Barbara J. [Instituto Tecnologia Quimica e Biologica, Universidade Nova de Lisboa, Oeiras (Portugal); Saraiva, Ligia M. [Instituto Tecnologia Quimica e Biologica, Universidade Nova de Lisboa, Oeiras (Portugal); Gomes, Claudio M. [Instituto Tecnologia Quimica e Biologica, Universidade Nova de Lisboa, Oeiras (Portugal)]. E-mail: gomes@itqb.unl.pt
2005-08-05T23:59:59.000Z
Rubredoxins are the simplest type of iron-sulphur proteins and in recent years they have been used as model systems in protein folding and stability studies, especially the proteins from thermophilic sources. Here, we report our studies on the rubredoxin from the hyperthermophile Methanococcus jannaschii (T {sub opt} = 85 deg C), which was investigated in respect to its thermal unfolding kinetics by temperature jump experiments. Different spectroscopic probes were used to monitor distinct structural protein features during the thermal transition: the integrity of the iron-sulphur centre was monitored by visible absorption spectroscopy, whereas tertiary structure was followed by intrinsic tryptophan fluorescence and exposure of protein hydrophobic patches was sensed by 1-anilinonaphthalene-8-sulphonate fluorescence. The studies were performed at acidic pH conditions in which any stabilising contributions from salt bridges are annulled due to protonation of protein side chain groups. In these conditions, M. jannaschii rubredoxin assumes a native-like, albeit more flexible and open conformation, as indicated by a red shift in the tryptophan emission maximum and 1-anilinonaphthalene-8-sulphonate binding. Temperature jumps were monitored by the three distinct techniques and showed that the protein undergoes thermal denaturation via a simple two step mechanism, as loss of tertiary structure, hydrophobic collapse, and disintegration of the iron-sulphur centre are concomitant processes. The proposed mechanism is framed with the multiphasic one proposed for Pyrococcus furiosus rubredoxin, showing that a common thermal unfolding mechanism is not observed between these two closely related thermophilic rubredoxins.
Potential climate change effects on Great Lakes hydrodynamics and water quality
Lam, D.C.L.; Schertzer, W.M. [eds.
1999-07-01T23:59:59.000Z
The problem of climate change has become increasingly recognized as a major environmental concern. Its impact can affect many socio-economic and ecosystem components. This book provides a state-of-the-art review of the climate change effects on lake hydrodynamics and water quality. Most of the engineering cases covered deal with the ability of existing infrastructure to cope with extreme weather conditions. The aim is to provide sufficient case studies to illustrate the advancement in modeling research on lake hydrodynamics, thermal stratification, pollutant transport and water quality by highlighting the climate change aspects in the application of these techniques.
Temperature-extrapolation method for Implicit Monte Carlo - Radiation hydrodynamics calculations
McClarren, R. G. [Department of Nuclear Engineering, Texas A and M University, 3133 TAMU, College Station, TX 77802 (United States); Urbatsch, T. J. [XTD-5: Air Force Systems, Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 77845 (United States)
2013-07-01T23:59:59.000Z
We present a method for implementing temperature extrapolation in Implicit Monte Carlo solutions to radiation hydrodynamics problems. The method is based on a BDF-2 type integration to estimate a change in material temperature over a time step. We present results for radiation only problems in an infinite medium and for a 2-D Cartesian hohlraum problem. Additionally, radiation hydrodynamics simulations are presented for an RZ hohlraum problem and a related 3D problem. Our results indicate that improvements in noise and general behavior are possible. We present considerations for future investigations and implementations. (authors)
Statistical Estimation of Two-Body Hydrodynamic Properties Using System Identification
Xie, Chen
2010-01-14T23:59:59.000Z
of Liquid Natural Gas (LNG). The offloading operations from the LNG terminal to the LNG carrier are conditioned by the arm-length of LNG off-loading lines and are also somewhat constrained by the fragility of the transportation lines due to extreme low... the hydrodynamic interaction effects in both the first order motions and the mean second order drift forces on a pair of closely positioned FPSO and LNG carrier. It was shown that the simplification of using free floating single body hydrodynamics to study...
Hydrodynamics and heat transfer aspects of corium-water interactions: Interim report
Spencer, B.W.; Sienicki, J.J.; McUmber, L.M.
1987-03-01T23:59:59.000Z
The results of reactor-material experiments are described in which molten corium entered a scaled mock-up of the reactor cavity region of a PWR containment. The experiments address ex-vessel cavity interactions such as corium quench and steam generation rates (for those cases in which water is present in the cavity), hydrodynamic dispersal of water and corim from the cavity, hydrogen generation, containment atmosphere heatup by dispersed corium, and debris characterization. Generic aspects of corium/water mixing, fragmentation, and quench were also investigated. The results include extensive modeling of the hydrodynamic and heat transfer processes and application of the models to the full size reactor system.
Di-jet hadron pair correlation in a hydrodynamical model with a quenching jet
A. K. Chaudhuri
2008-01-15T23:59:59.000Z
In jet quenching, a hard QCD parton, before fragmenting into a jet of hadrons, deposits a fraction of its energy in the medium, leading to suppressed production of high-$p_T$ hadrons. Assuming that the deposited energy quickly thermalizes, we simulate the subsequent hydrodynamic evolution of the QGP fluid. Hydrodynamic evolution and subsequent particle emission depend on the jet trajectories. Azimuthal distribution of excess $\\pi^-$ due to quenching jet, averaged over all the trajectories, reasonably well reproduce the di-hadron correlation as measured by the STAR and PHENIX collaboration in central and in peripheral Au+Au collisions.
Spin current evolution in the separated spin-up and spin-down quantum hydrodynamics
Trukhanova, Mariya Iv
2015-01-01T23:59:59.000Z
We have developed the quantum hydrodynamic model that describes particles with spin-up and with spin-down in separate. We have derived the equation of the spin current evolution as a part of the set of the quantum hydrodynamics (QHD) equations that treat particles with different projection of spin on the preferable direction as two different species. We have studied orthogonal propagation of waves in the external magnetic field and determined the contribution of quantum corrections due to the Bohm potential and to magnetization energy of particles with different projections of spin in the spin current wave dispersion. We have analyzed the limits of weak and strong magnetic fields.
Reliable estimation of shock position in shock-capturing compressible hydrodynamics codes
Nelson, Eric M [Los Alamos National Laboratory
2008-01-01T23:59:59.000Z
The displacement method for estimating shock position in a shock-capturing compressible hydrodynamics code is introduced. Common estimates use simulation data within the captured shock, but the displacement method uses data behind the shock, making the estimate consistent with and as reliable as estimates of material parameters obtained from averages or fits behind the shock. The displacement method is described in the context of a steady shock in a one-dimensional lagrangian hydrodynamics code, and demonstrated on a piston problem and a spherical blast wave.The displacement method's estimates of shock position are much better than common estimates in such applications.
Order and chaos in hydrodynamic BL Her models
R. Smolec; P. Moskalik
2013-09-23T23:59:59.000Z
Many dynamical systems of different complexity, e.g. 1D logistic map, the Lorentz equations, or real phenomena, like turbulent convection, show chaotic behaviour. Despite huge differences, the dynamical scenarios for these systems are strikingly similar: chaotic bands are born through the series of period doubling bifurcations and merge through interior crises. Within chaotic bands periodic windows are born through the tangent bifurcations, preceded by the intermittent behaviour. This is a universal behaviour of dynamical systems (Feigenbaum 1983). We demonstrate such behaviour in models of pulsating stars.
Fleenor, William E.; Bombardelli, Fabian
2013-01-01T23:59:59.000Z
Hydrodynamic and Salinity Transport Modeling of the Sacramento–San Joaquin Delta: Sea Level Rise and Water Diversion Effects
Effect of Second-Order Hydrodynamics on Floating Offshore Wind Turbines: Preprint
Roald, L.; Jonkman, J.; Robertson, A,; Chokani, N.
2013-07-01T23:59:59.000Z
Offshore winds are generally stronger and more consistent than winds on land, making the offshore environment attractive for wind energy development. A large part of the offshore wind resource is however located in deep water, where floating turbines are the only economical way of harvesting the energy. The design of offshore floating wind turbines relies on the use of modeling tools that can simulate the entire coupled system behavior. At present, most of these tools include only first-order hydrodynamic theory. However, observations of supposed second-order hydrodynamic responses in wave-tank tests performed by the DeepCwind consortium suggest that second-order effects might be critical. In this paper, the methodology used by the oil and gas industry has been modified to apply to the analysis of floating wind turbines, and is used to assess the effect of second-order hydrodynamics on floating offshore wind turbines. The method relies on combined use of the frequency-domain tool WAMIT and the time-domain tool FAST. The proposed assessment method has been applied to two different floating wind concepts, a spar and a tension-leg-platform (TLP), both supporting the NREL 5-MW baseline wind turbine. Results showing the hydrodynamic forces and motion response for these systems are presented and analysed, and compared to aerodynamic effects.
Luo, Haoxiang
An efficient immersed boundary-lattice Boltzmann method for the hydrodynamic interaction of elastic flapping in the Kármán gait and the entrainment regions near a cylinder is studied to model fish swimming in these regions. Significant drag reduction is found for the filament, and the result is consistent
EFFECTS OF CHAMBER GEOMETRY AND GAS PROPERTIES ON HYDRODYNAMIC EVOLUTION OF IFE Zoran Dragojlovic1
Najmabadi, Farrokh
-rays and ions travel through the chamber and deposit some of their energy in the chamber background gas; the effects of various heat sources and transfer mechanisms such as photon and ion heat deposition and chamberEFFECTS OF CHAMBER GEOMETRY AND GAS PROPERTIES ON HYDRODYNAMIC EVOLUTION OF IFE CHAMBERS Zoran
Tlusty, Tsvi
Anomalous Microfluidic Phonons Induced by the Interplay of Hydrodynamic Screening the acoustic normal modes (``phonons'') of a 1D microfluidic droplet crystal at the crossover between 2D flow.55.Dÿ, 47.60.+i, 47.63.mf, 63.22.+m Microfluidic two-phase flow offers experimental tools to investigate
Hydrodynamic forces and surface topography: Centimeter-scale spatial variation in wave forces
Denny, Mark
Hydrodynamic forces and surface topography: Centimeter-scale spatial variation in wave forces. On the rugose rock surfaces of wave-swept shores, interactions between substratum topography and wave-induced flow may create such a spatially variable environment. Topography Numerous investigators have explored
XXII ICTAM, 2529 August 2008, Adelaide, Australia PERISTALSIS AND HYDRODYNAMIC INSTABILITIES
Hoepffner, Jérôme
in hydrodynamic instabilities. A propagating wall deformation generates pressure gradients in the flow, which act channel has its height reduced as if locally constricted by a cuff, sliding towards the right. The wall to the propagation of the constricted region, a high pressure is generated in P1 where the fluid is pushed down
Core-annular flow through a horizontal pipe: Hydrodynamic counterbalancing of buoyancy force on core
Vuik, Kees
Core-annular flow through a horizontal pipe: Hydrodynamic counterbalancing of buoyancy force of a high-viscosity liquid core surrounded by a low-viscosity liquid annular layer through a horizontal pipe through a horizontal pipe. Since the densities of the two liq- uids are almost always different, gravity
GENERIC HYDRODYNAMIC INSTABILITY OF CURL EIGENFIELDS JOHN ETNYRE AND ROBERT GHRIST
Ghrist, Robert W.
GENERIC HYDRODYNAMIC INSTABILITY OF CURL EIGENFIELDS JOHN ETNYRE AND ROBERT GHRIST ABSTRACT. We prove that for generic geometry, the curl-eigenfield solutions to the steady Euler equations on R3 /Z3 class of flows -- the curl eigenfields -- which form the most fascinating and challenging steady
Porous Superhydrophobic Membranes: Hydrodynamic Anomaly in Oscillating Flows S. Rajauria,1,2
that a stable Knudsen layer of gas percolates on the membrane, changing the boundary condition. This is be simultaneously. Oscillatory hydrodynamic measurements on porous superhydropho- bic membranes as a function of Ès Knudsen layer of air at the interface. DOI: 10.1103/PhysRevLett.107.174501 PACS numbers: 47.61.Àk, 47
Berlyand, Leonid
Viscosity of Bacterial Suspensions: Hydrodynamic Interactions and Self-Induced Noise Shawn D. Ryan, 2011) The viscosity of a suspension of swimming bacteria is investigated analytically and numerically fluid, result in a dramatic reduction of the effective viscosity. In agreement with experiments
Fischer, Paul F.
-averaged Navier- Stokes) and subchannel models. Our initial study is focused on LES of sodium-cooled fast reactorPetascale Algorithms for Reactor Hydrodynamics Paul Fischer, James Lottes, David Pointer, and Andew describe recent algorithmic developments that have enabled large eddy simulations of reactor flows on up
A microfluidic-based hydrodynamic trap: design and implementation Melikhan Tanyeri,a
Schroeder, Charles
A microfluidic-based hydrodynamic trap: design and implementation Melikhan Tanyeri,a Mikhil Ranka: 10.1039/c0lc00709a We report an integrated microfluidic device for fine-scale manipulation in a monolithic PDMS-based microfluidic device. In this work, we characterize device design parameters enabling
Hydrodynamic and Structural Performance of the Transverse Horizontal Axis Water Turbine
Gorban, Alexander N.
Hydrodynamic and Structural Performance of the Transverse Horizontal Axis Water Turbine Prof. Guy across the flow THAWT Concept Transverse Horizontal Axis Water Turbine · Length limited only by stiffness;Options for tidal stream power (1) · Axial flow turbines ("underwater windmills") "Unducted" » MCT (most
One dimensional electromagnetic relativistic PIC-hydrodynamic hybrid simulation code H-VLPL
Grimm, Volker
One dimensional electromagnetic relativistic PIC-hydrodynamic hybrid simulation code H-VLPL (Hybrid full electromagnetic relativistic hybrid plasma model. The full kinetic particle-in cell (PIC, there is a demand to simulate high density plasmas, e.g., in the experiments where the laser pulse interacts
Dual Axis Radiographic Hydrodynamic Test Facility mitigation action plan. Annual report for 1998
Haagenstad, T.
1999-01-15T23:59:59.000Z
This Mitigation Action Plan Annual Report (MAPAR) has been prepared as part of implementing the Dual Axis Radiographic Hydrodynamic Test Facility (DARHT) Mitigation Action Plan (MAP) to protect workers, soils, water, and biotic and cultural resources in and around the facility.
Chemistry Induced by Hydrodynamic Cavitation Kenneth S. Suslick,* Millan M. Mdleleni, and
Suslick, Kenneth S.
Chemistry Induced by Hydrodynamic Cavitation Kenneth S. Suslick,* Millan M. Mdleleni, and Jeffrey T, Urbana, Illinois 61801 ReceiVed July 1, 1997 Cavitation (the formation, growth, and implosive collapse the chemical effects of acoustic cavitation (i.e., sonochemistry and sonoluminescence) have been extensively
Hydrodynamic cavitation and boiling in refrigerant (R-123) flow inside microchannels
Peles, Yoav
Hydrodynamic cavitation and boiling in refrigerant (R-123) flow inside microchannels Brandon cavitation has on heat transfer. The fluid medium is refrigerant R-123 flowing through 227 lm hydraulic diameter microchannels. The cavitation is instigated by the inlet orifice. Adiabatic tests were con- ducted
Lucas J. Fernández-Alcázar; Horacio M. Pastawski
2015-02-27T23:59:59.000Z
We present a model for decoherence in time-dependent transport. It boils down into a form of wave function that undergoes a smooth stochastic drift of the phase in a local basis, the Quantum Drift (QD) model. This drift is nothing else but a local energy fluctuation. Unlike Quantum Jumps (QJ) models, no jumps are present in the density as the evolution is unitary. As a first application, we address the transport through a resonant state $\\left\\vert 0\\right\\rangle $ that undergoes decoherence. We show the equivalence with the decoherent steady state transport in presence of a B\\"{u}ttiker's voltage probe. In order to test the dynamics, we consider two many-spin systems whith a local energy fluctuation. A two-spin system is reduced to a two level system (TLS) that oscillates among $\\left\\vert 0\\right\\rangle $ $\\equiv $ $ \\left\\vert \\uparrow \\downarrow \\right\\rangle $ and $\\left\\vert 1\\right\\rangle \\equiv $ $\\left\\vert \\downarrow \\uparrow \\right\\rangle $. We show that QD model recovers not only the exponential damping of the oscillations in the low perturbation regime, but also the non-trivial bifurcation of the damping rates at a critical point, i.e. the quantum dynamical phase transition. We also address the spin-wave like dynamics of local polarization in a spin chain. The QD average solution has about half the dispersion respect to the mean dynamics than QJ. By evaluating the Loschmidt Echo (LE), we find that the pure states $\\left\\vert 0\\right\\rangle $ and $\\left\\vert 1\\right \\rangle $ are quite robust against the local decoherence. In contrast, the LE, and hence coherence, decays faster when the system is in a superposition state. Because its simple implementation, the method is well suited to assess decoherent transport problems as well as to include decoherence in both one-body and many-body dynamics.
Denny, Mark
A limpet shell shape that reduces drag: laboratory demonstration of a hydrodynamic mechanism shell shape that reduces drag: laboratory demonstration of a hydrodynamic mechanism and an exploration that reduces drag: laboratory demonstration of a hydrodynamic mechanism and an exploration of its effectiveness
A pulsed power hydrodynamics approach to exploring properties of warm dense matter
Reinovsky, Robert Emil [Los Alamos National Laboratory
2008-01-01T23:59:59.000Z
Pulsed Power Hydrodynamics, as an application of low-impedance, pulsed power, and high magnetic field technology developed over the last decade to study advanced hydrodynamic problems, instabilities, turbulence, and material properties, can potentially be applied to the study of the behavior and properties of warm dense matter (WDM) as well. Exploration of the properties, such as equation of state and conductivity, of warm dense matter is an emerging area of study focused on the behavior of matter at density near solid density (from 10% of solid density to a few times solid density) and modest temperatures ({approx}1-10 eV). Warm dense matter conditions can be achieved by laser or particle beam heating of very small quantities of matter on timescales short compared to the subsequent hydrodynamic expansion timescales (isochoric heating) and a vigorous community of researchers is applying these techniques using petawatt scale laser systems, but the microscopic size scale of the WDM produced in this way limits access to some physics phenomena. Pulsed power hydrodynamics techniques, either through high convergence liner compression of a large volume, modest density, low temperature plasma to densities approaching solid density or through the explosion and subsequent expansion of a conductor (wire) against a high pressure (density) gas background (isobaric expansion) techniques both offer the prospect for producing warm dense matter in macroscopic quantities. However, both techniques demand substantial energy, proper power conditioning and delivery, and an understanding of the hydrodynamic and instability processes that limit each technique. Similarly, liner compression of normal density material, perhaps using multiple reflected shocks can provide access to the challenging region above normal density -- again with the requirement of very large amounts of driving energy. In this paper we will provide an introduction to techniques that might be applied to explore this interesting new application of the energy-rich technology of pulse power and high magnetic fields.
Julie Napier
2015-04-22T23:59:59.000Z
150 N. University Street. West Lafayette IN, 47907-2067 ... Highest degree from an accredited college/university ... ______ Library professional staff. ______ ...
Hydrodynamic heave damping estimation and scaling for tension leg platforms
Thiagarajan, K.P.; Troesch, A.W. (Univ. of Michigan, Ann Arbor, MI (United States))
1994-05-01T23:59:59.000Z
Resonant heave excitation of tension leg platform (TLP) tendons is typically of high-frequency and small amplitude. The response of the tendons to this excitation is non-negligible due to a very small drag coefficient of the structure in this mode of oscillation. Small values of the drag force complicate experimental estimation in a laboratory due to the dominating inertial force. Model tests conducted at the University of Michigan investigating the damping experienced by a cylinder of 0.457 m (1.5 ft) diameter and 1.219 m (4.0 ft) draft are described here. The cylinder is vertical and surface-piercing, and oscillates parallel to its axis. The amplitude of the forcing is varied to give a Keulegan-Carpenter (KC) number range of 0.1--1.0. The frequency parameter [beta] is 89236, corresponding to an oscillation frequency of 0.41 Hz. From these experiments, a definite nonlinear trend is observed between the drag force and velocity conflicting with some of the results reported by Huse (1990) and Chakrabarti and Hanna (1991). The heave damping coefficients of individual structural components of a TLP follow different scaling laws. Rules are presented for scaling friction and form drag components from model to full scale. Results from experiments are used to obtain a scaling law for vertical columns of a TLP. Previously published results are used for horizontal pontoons. An example TLP calculation shows that the heave damping ratio of horizontal cylinders is approximately 0.049--0.078 percent, depending upon cylinder shape, and that for vertical cylinders is in the range 0.025--0.171 percent, depending upon KC.
Thomas B. Schroder; Ulf R. Pedersen; Nicoletta Gnan; Jeppe C. Dyre
2009-03-03T23:59:59.000Z
Computer simulations recently revealed that several liquids exhibit strong correlations between virial and potential energy equilibrium fluctuations in the NVT ensemble [U. R. Pedersen {\\it et al.}, Phys. Rev. Lett. {\\bf 100}, 015701 (2008)]. In order to investigate whether these correlations are present also far from equilibrium constant-volume aging following a temperature down jump from equilibrium was simulated for two strongly correlating liquids, an asymmetric dumbbell model and Lewis-Wahnstr{\\"o}m OTP, as well as for SPC water that is not strongly correlating. For the two strongly correlating liquids virial and potential energy follow each other closely during the aging towards equilibrium. For SPC water, on the other hand, virial and potential energy vary with little correlation as the system ages towards equilibrium. Further proof that strong pressure-energy correlations express a configuration space property comes from monitoring pressure and energy during the crystallization (reported here for the first time) of supercooled Lewis-Wahnstr{\\"o}m OTP at constant temperature.
Kinetic freeze-out, particle spectra and harmonic flow coefficients from mode-by-mode hydrodynamics
Stefan Floerchinger; Urs Achim Wiedemann
2014-08-27T23:59:59.000Z
The kinetic freeze-out for the hydrodynamical description of relativistic heavy ion collisions is discussed using a background-fluctuation splitting of the hydrodynamical fields. For a single event, the particle spectrum, or its logarithm, can be written as the sum of background part that is symmetric with respect to azimuthal rotations and longitudinal boosts and a part containing the contribution of fluctuations or deviations from the background. Using a complete orthonormal basis to characterize the initial state allows one to write the double differential harmonic flow coefficients determined by the two-particle correlation method as matrix expressions involving the initial fluid correlations. We discuss the use of these expressions for a mode-by-mode analysis of fluctuating initial conditions in heavy ion collisions.
Super stellar clusters with a bimodal hydrodynamic solution: an Approximate Analytic Approach
Wünsch, R; Palous, J; Tenorio-Tagle, G
2007-01-01T23:59:59.000Z
We look for a simple analytic model to distinguish between stellar clusters undergoing a bimodal hydrodynamic solution from those able to drive only a stationary wind. Clusters in the bimodal regime undergo strong radiative cooling within their densest inner regions, which results in the accumulation of the matter injected by supernovae and stellar winds and eventually in the formation of further stellar generations, while their outer regions sustain a stationary wind. The analytic formulae are derived from the basic hydrodynamic equations. Our main assumption, that the density at the star cluster surface scales almost linearly with that at the stagnation radius, is based on results from semi-analytic and full numerical calculations. The analytic formulation allows for the determination of the threshold mechanical luminosity that separates clusters evolving in either of the two solutions. It is possible to fix the stagnation radius by simple analytic expressions and thus to determine the fractions of the depo...
Hydrodynamic flow in the vicinity of a nanopore induced by an applied voltage
Mao, Mao; Hu, Guohui
2013-01-01T23:59:59.000Z
Continuum simulation is employed to study ion transport and fluid flow through a nanopore in a solid-state membrane under an applied potential drop. Results show the existence of concentration polarization layers on the surfaces of the membrane. The nonuniformity of the ionic distribution gives rise to an electric pressure that drives vortical motion in the fluid. There is also a net hydrodynamic flow through the nanopore due to an asymmetry induced by the membrane surface charge. The qualitative behavior is similar to that observed in a previous study using molecular dynamic simulations. The current--voltage characteristics show some nonlinear features but are not greatly affected by the hydrodynamic flow in the parameter regime studied. In the limit of thin Debye layers, the electric resistance of the system can be characterized using an equivalent circuit with lumped parameters. Generation of vorticity can be understood qualitatively from elementary considerations of the Maxwell stresses. However, the flow...
Low torque hydrodynamic lip geometry for bi-directional rotation seals
Dietle, Lannie L. (Houston, TX); Schroeder, John E. (Richmond, TX)
2011-11-15T23:59:59.000Z
A hydrodynamically lubricating geometry for the generally circular dynamic sealing lip of rotary seals that are employed to partition a lubricant from an environment. The dynamic sealing lip is provided for establishing compressed sealing engagement with a relatively rotatable surface, and for wedging a film of lubricating fluid into the interface between the dynamic sealing lip and the relatively rotatable surface in response to relative rotation that may occur in the clockwise or the counter-clockwise direction. A wave form incorporating an elongated dimple provides the gradual convergence, efficient impingement angle, and gradual interfacial contact pressure rise that are conducive to efficient hydrodynamic wedging. Skewed elevated contact pressure zones produced by compression edge effects provide for controlled lubricant movement within the dynamic sealing interface between the seal and the relatively rotatable surface, producing enhanced lubrication and low running torque.
Low torque hydrodynamic lip geometry for bi-directional rotation seals
Dietle, Lannie L. (Houston, TX); Schroeder, John E. (Richmond, TX)
2009-07-21T23:59:59.000Z
A hydrodynamically lubricating geometry for the generally circular dynamic sealing lip of rotary seals that are employed to partition a lubricant from an environment. The dynamic sealing lip is provided for establishing compressed sealing engagement with a relatively rotatable surface, and for wedging a film of lubricating fluid into the interface between the dynamic sealing lip and the relatively rotatable surface in response to relative rotation that may occur in the clockwise or the counter-clockwise direction. A wave form incorporating an elongated dimple provides the gradual convergence, efficient impingement angle, and gradual interfacial contact pressure rise that are conducive to efficient hydrodynamic wedging. Skewed elevated contact pressure zones produced by compression edge effects provide for controlled lubricant movement within the dynamic sealing interface between the seal and the relatively rotatable surface, producing enhanced lubrication and low running torque.
Sienicki, J.J.; Spencer, B.W.
1984-01-01T23:59:59.000Z
An analysis of hydrodynamic phenomena in simulant experiments examining aspects of ex-vessel material interactions in a PWR reactor cavity following postulated core meltdown and localized breaching of the reactor vessel has been carried out. While previous analyses of the tests examined thresholds for the onset of sweepout of fluid from the cavity, the present analysis considers the progression of specific hydrodynamic phenomena involved in the dispersal process: crater formation due to gas jet impingement, radial wave motion and growth, entrainment and transport of liquid droplets, liquid layer formation due to droplet recombination, fluidization of liquid remaining in the cavity, removal of fluidized liquid droplets from the cavity, and the ultimate removal of the remaining liquid layer within the tunnel passageway. Phenomenological models which may be used to predict the phenomena are presented.
Hydrodynamic models of self-organized dynamics: derivation and existence theory
Pierre Degond; Jian-Guo Liu; Sébastien Motsch; Vladislav Panferov
2011-08-16T23:59:59.000Z
This paper is concerned with the derivation and analysis of hydrodynamic models for systems of self-propelled particles subject to alignment interaction and attraction-repulsion. The starting point is the kinetic model considered in earlier work of Degond & Motsch with the addition of an attraction-repulsion interaction potential. Introducing different scalings than in Degond & Motsch, the non-local effects of the alignment and attraction-repulsion interactions can be kept in the hydrodynamic limit and result in extra pressure, viscosity terms and capillary force. The systems are shown to be symmetrizable hyperbolic systems with viscosity terms. A local-in-time existence result is proved in the 2D case for the viscous model and in the 3D case for the inviscid model. The proof relies on the energy method.
Tung, Ryan C., E-mail: ryan.tung@nist.gov; Killgore, Jason P.; Hurley, Donna C. [National Institute of Standards and Technology, Boulder, Colorado 80305 (United States)
2014-06-14T23:59:59.000Z
We present a method to correct for surface-coupled inertial and viscous fluid loading forces in contact resonance (CR) atomic force microscopy (AFM) experiments performed in liquid. Based on analytical hydrodynamic theory, the method relies on experimental measurements of the AFM cantilever's free resonance peaks near the sample surface. The free resonance frequencies and quality factors in both air and liquid allow reconstruction of a continuous hydrodynamic function that can be used to adjust the CR data in liquid. Validation experiments utilizing thermally excited free and in-contact spectra were performed to assess the accuracy of our approach. Results show that the method recovers the air frequency values within approximately 6%. Knowledge of fluid loading forces allows current CR analysis techniques formulated for use in air and vacuum environments to be applied to liquid environments. Our technique greatly extends the range of measurement environments available to CR-AFM.
Non-Abelian hydrodynamics and the flow of spin in spin-orbit coupled substances
Leurs, B.W.A. [Instituut Lorentz for Theoretical Physics, Leiden University, Leiden (Netherlands)], E-mail: leurs@lorentz.leidenuniv.nl; Nazario, Z.; Santiago, D.I.; Zaanen, J. [Instituut Lorentz for Theoretical Physics, Leiden University, Leiden (Netherlands)
2008-04-15T23:59:59.000Z
Motivated by the heavy ion collision experiments there is much activity in studying the hydrodynamical properties of non-Abelian (quark-gluon) plasmas. A major question is how to deal with color currents. Although not widely appreciated, quite similar issues arise in condensed matter physics in the context of the transport of spins in the presence of spin-orbit coupling. The key insight is that the Pauli Hamiltonian governing the leading relativistic corrections in condensed matter systems can be rewritten in a language of SU(2) covariant derivatives where the role of the non-Abelian gauge fields is taken by the physical electromagnetic fields: the Pauli system can be viewed as Yang-Mills quantum-mechanics in a 'fixed frame', and it can be viewed as an 'analogous system' for non-Abelian transport in the same spirit as Volovik's identification of the He superfluids as analogies for quantum fields in curved space time. We take a similar perspective as Jackiw and coworkers in their recent study of non-Abelian hydrodynamics, twisting the interpretation into the 'fixed frame' context, to find out what this means for spin transport in condensed matter systems. We present an extension of Jackiw's scheme: non-Abelian hydrodynamical currents can be factored in a 'non-coherent' classical part, and a coherent part requiring macroscopic non-Abelian quantum entanglement. Hereby it becomes particularly manifest that non-Abelian fluid flow is a much richer affair than familiar hydrodynamics, and this permits us to classify the various spin transport phenomena in condensed matter physics in an unifying framework. The 'particle based hydrodynamics' of Jackiw et al. is recognized as the high temperature spin transport associated with semiconductor spintronics. In this context the absence of faithful hydrodynamics is well known, but in our formulation it is directly associated with the fact that the covariant conservation of non-Abelian currents turns into a disastrous non-conservation of the incoherent spin currents of the high temperature limit. We analyze the quantum-mechanical single particle currents of relevance to mesoscopic transport with as highlight the Ahronov-Casher effect, where we demonstrate that the intricacies of the non-Abelian transport render this effect to be much more fragile than its abelian analog, the Ahronov-Bohm effect. We subsequently focus on spin flows protected by order parameters. At present there is much interest in multiferroics where non-collinear magnetic order triggers macroscopic electric polarization via the spin-orbit coupling. We identify this to be a peculiarity of coherent non-Abelian hydrodynamics: although there is no net particle transport, the spin entanglement is transported in these magnets and the coherent spin 'super' current in turn translates into electric fields with the bonus that due to the requirement of single valuedness of the magnetic order parameter a true hydrodynamics is restored. Finally, 'fixed-frame' coherent non-Abelian transport comes to its full glory in spin-orbit coupled 'spin superfluids', and we demonstrate a new effect: the trapping of electrical line charge being a fixed frame, non-Abelian analog of the familiar magnetic flux trapping by normal superconductors. The only known physical examples of such spin superfluids are the {sup 3}He A- and B-phase where unfortunately the spin-orbit coupling is so weak that it appears impossible to observe these effects.
Running faster together: huge speed up of thermal ratchets due to hydrodynamic coupling
Paolo Malgaretti; Ignacio Pagonabarraga; Daan Frenkel
2012-09-19T23:59:59.000Z
We present simulations that reveal a surprisingly large effect of hydrodynamic coupling on the speed of thermal ratchet motors. The model that we use considers particles performing thermal ratchet motion in a hydrodynamic solvent. Using particle-based, mesoscopic simulations that maintain local momentum conservation, we analyze quantitatively how the coupling to the surrounding fluid affects ratchet motion. We find that coupling can increase the mean velocity of the moving particles by almost two orders of magnitude, precisely because ratchet motion has both a diffusive and a deterministic component. The resulting coupling also leads to the formation of aggregates at longer times. The correlated motion that we describe increases the efficiency of motor-delivered cargo transport and we speculate that the mechanism that we have uncovered may play a key role in speeding up molecular motor-driven intracellular transport.
Schaal, Kevin; Chandrashekar, Praveen; Pakmor, Rüdiger; Klingenberg, Christian; Springel, Volker
2015-01-01T23:59:59.000Z
Solving the Euler equations of ideal hydrodynamics as accurately and efficiently as possible is a key requirement in many astrophysical simulations. It is therefore important to continuously advance the numerical methods implemented in current astrophysical codes, especially also in light of evolving computer technology, which favours certain computational approaches over others. Here we introduce the new adaptive mesh refinement (AMR) code TENET, which employs a high-order Discontinuous Galerkin (DG) scheme for hydrodynamics. The Euler equations in this method are solved in a weak formulation with a polynomial basis by means of explicit Runge-Kutta time integration and Gauss-Legendre quadrature. This approach offers significant advantages over commonly employed finite volume (FV) solvers. In particular, the higher order capability renders it computationally more efficient, in the sense that the same precision can be obtained at significantly less computational cost. Also, the DG scheme inherently conserves a...
Paul, Ephraim Udo
2011-02-22T23:59:59.000Z
This study was conducted to ascertain the impacts of bed leveling, following ship channel dredging operations, and to also investigate the hydrodynamic flow field around box bed levelers. Laboratory experiments were conducted with bed levelers...
Rominger, Jeffrey T. (Jeffrey Tsaros)
2014-01-01T23:59:59.000Z
From the canopy scale to the blade scale, interactions between fluid motion and kelp produce a wide array of hydrodynamic and scalar transport phenomena. At the kilometer scale of the kelp forest, coastal currents transport ...
Gidaspow, D.
1996-04-01T23:59:59.000Z
The objective of this investigation is to convert our ``learning gas solid-liquid`` fluidization model into a predictive design model. The IIT hydrodynamic model computes the phase velocities and the volume fractions of gas, liquid and particulate phase. Model verification involves a comparison of these computed velocities and volume fractions to experimental values. A hydrodynamic model for multiphase flows, based on the principles of mass, momentum and energy conservation for each phase, was developed and applied to model gas-liquid, gas-liquid-solid fluidization and gas-solid-solid separation. To simulate the industrial slurry bubble column reactors, a computer program based on the hydrodynamic model was written with modules for chemical reactions (e.g. the synthesis of methanol), phase changes and heat exchangers. In the simulations of gas-liquid two phases flow system, the gas hold-ups, computed with a variety of operating conditions such as temperature, pressure, gas and liquid velocities, agree well with the measurements obtained at Air Products` pilot plant. The hydrodynamic model has more flexible features than the previous empirical correlations in predicting the gas hold-up of gas-liquid two-phase flow systems. In the simulations of gas-liquid-solid bubble column reactors with and without slurry circulation, the code computes volume fractions, temperatures and velocity distributions for the gas, the liquid and the solid phases, as well as concentration distributions for the species (CO, H{sub 2}, CH{sub 3}0H, ... ), after startup from a certain initial state. A kinetic theory approach is used to compute a solid viscosity due to particle collisions. Solid motion and gas-liquid-solid mixing are observed on a color PCSHOW movie made from computed time series data. The steady state and time average catalyst concentration profiles, the slurry height and the rates of methanol production agree well with the measurements obtained at an Air Products` pilot plant.
Starrfield, S.; Kenyon, S.; Truran, J.W.; Sparks, W.M.
1983-01-01T23:59:59.000Z
We have used a Lagrangian, hydrodynamic stellar-evolution computer code to evolve a thermonuclear runaway in the accreted hydrogen rich envelope of a 1.0M, 10-km neutron star. Our simulation produced an outburst which lasted about 2000 sec and peak effective temperature was 3 keV. The peak luminosity exceeded 2 x 10/sup 5/ L. A shock wave caused a precursor in the light curve which lasted 10/sup -5/ sec.
Simulation study of the effect of hydrodynamic forces on oil recovery
Idrobo Hurtado, Eduardo Alejandro
1992-01-01T23:59:59.000Z
the potential at the intersections of the oil-water contacts of a specific grid pattern in Mishrif Fields, offshore Iran. They determined the inclinations of the oil-water contacts from the changes of potential. Tsenng in 1983 used a computer simulator... to study hydrodynamic flow in the Lower Cretaceous Muddy Sandstone, Bell Creek Field, Montana. The potentiometric surfaces were found to be influenced not only by the permeability variations but also by vertical permeability. However, in this case...
Hydrodynamic flow in lower Cretaceous Muddy sandstone, Gas Draw Field, Powder River Basin, Wyoming
Lin, Joseph Tien-Chin
1978-01-01T23:59:59.000Z
control readily available for analysis of rock properties and fluid pressures. The nine-township area surrounding the Gas Draw field is well-suited for study of hydrodynamic effects on oil accumulation. Regional Geology Structure The citations... of southeastern Montana. It is bounded by the Miles City arch and Black Hills uplift on the east, the Hartville uplift on the southeast, and Bighorn Mountains and Casper arch on the west. Muddy stratigraphic oil fields are located on the east flank...
Development and evaluation of a coupled hydrodynamic (FVCOM) and water quality model (CE-QUAL-ICM)
Kim, Taeyun; Labiosa, Rochelle G.; Khangaonkar, Tarang; Yang, Zhaoqing; Chen, Changsheng; Qi, Jianhua; Cerco, Carl
2010-01-08T23:59:59.000Z
Recent and frequent fish-kills in waters otherwise known for their pristine high quality, created increased awareness and urgent concern regarding potential for degradation of water quality in Puget Sound through coastal eutrophication caused by increased nutrient loading. Following a detailed review of leading models and tools available in public domain, FVCOM and CE-QUAL-ICM models were selected to conduct hydrodynamic and water quality simulations for the fjordal waters of Puget Sound.
Neutrino transport and hydrodynamic stability of rotating proto-neutron stars
V. Urpin
2007-04-24T23:59:59.000Z
We consider stability of differentially rotating non-magnetic proto-neutron stars. When neutrino transport is efficient, the star can be subject to a diffusive instability that can occur even in the convectively stable region. The instability arises on the time-scale comparable to the time-scale of thermal diffusion. Hydrodynamic motions driven by the instability can lead to anisotropy in the neutrino flux since the instability is suppressed near the equator and rotation axis.
General relativistic radiation hydrodynamics of accretion flows. I: Bondi-Hoyle accretion
Olindo Zanotti; Constanze Roedig; Luciano Rezzolla; Luca Del Zanna
2015-03-10T23:59:59.000Z
We present a new code for performing general-relativistic radiation-hydrodynamics simulations of accretion flows onto black holes. The radiation field is treated in the optically-thick approximation, with the opacity contributed by Thomson scattering and thermal bremsstrahlung. Our analysis is concentrated on a detailed numerical investigation of hot two-dimensional, Bondi-Hoyle accretion flows with various Mach numbers. We find significant differences with respect to purely hydrodynamical evolutions. In particular, once the system relaxes to a radiation-pressure dominated regime, the accretion rates become about two orders of magnitude smaller than in the purely hydrodynamical case, remaining however super-Eddington as are the luminosities. Furthermore, when increasing the Mach number of the inflowing gas, the accretion rates become smaller because of the smaller cross section of the black hole, but the luminosities increase as a result a stronger emission in the shocked regions. Overall, our approach provides the first self-consistent calculation of the Bondi-Hoyle luminosity, most of which is emitted within r~100 M from the black hole, with typical values L/L_Edd ~ 1-7, and corresponding energy efficiencies eta_BH ~ 0.09-0.5. The possibility of computing luminosities self-consistently has also allowed us to compare with the bremsstrahlung luminosity often used in modelling the electromagnetic counterparts to supermassive black-hole binaries, to find that in the optically-thick regime these more crude estimates are about 20 times larger than our radiation-hydrodynamics results.
Larberg, Gregory Martin
1976-01-01T23:59:59.000Z
stratigraphic traps in the Lower Cretaceous Muddy Sandstones on the east flank of the basin (Figure 1). The nine ? township area immediately surrounding Kitty in- cludes Kingsbury and Mill ? Gillette fields and is well ? suited for hydrodynamic study because... understanding of the relationships between pressures, flow, and the rocks themselves. 14 Nethods Subsurface data from the nine township area surround- ing Kitty field is abundant and readily available from in- dustry sources. Over 530 class "A" (analyzable...
Granular Solid Hydrodynamics (GSH): a broad-ranged macroscopic theory of granular media
Yimin Jiang; Mario Liu
2014-07-27T23:59:59.000Z
A unified continuum-mechanical theory has been until now lacking for granular media, some believe it could not exist. Derived employing the hydrodynamic approach, GSH is such a theory, though as yet a qualitative one. The behavior being accounted for includes static stress distribution, elastic wave, elasto-plastic motion, the critical state and rapid dense flow. The equations and application to a few typical experiments are presented here.
Hydrodynamic Crossovers in Surface-Directed Spinodal Decomposition and Surface Enrichment
Prabhat K. Jaiswal; Sanjay Puri; Subir K. Das
2010-11-29T23:59:59.000Z
We present comprehensive molecular dynamics (MD) results for the kinetics of surface-directed spinodal decomposition (SDSD) and surface enrichment (SE) in binary mixtures at wetting surfaces. We study the surface morphology and the growth dynamics of the wetting and enrichment layers. The growth law for the thickness of these layers shows a crossover from a diffusive regime to a hydrodynamic regime. We provide phenomenological arguments to understand this crossover.
Causal hydrodynamics from kinetic theory by doublet scheme in renormalization-group method
Kyosuke Tsumura; Teiji Kunihiro
2014-09-10T23:59:59.000Z
We develop a general framework in the renormalization-group (RG) method for extracting a mesoscopic dynamics from an evolution equation by incorporating some excited (fast) modes as additional components to the invariant manifold spanned by zero modes. We call this framework the doublet scheme. We apply the doublet scheme to construct causal hydrodynamics as a mesoscopic dynamics of kinetic theory, i.e., the Boltzmann equation, in a systematic manner with no ad-hoc assumption. It is found that our equation has the same form as Grad's thirteen-moment causal hydrodynamic equation, but the microscopic formulae of the transport coefficients and relaxation times are different. In fact, in contrast to the Grad equation, our equation leads to the same expressions for the transport coefficients as given by the Chapman-Enskog expansion method and suggests novel formulae of the relaxation times expressed in terms of relaxation functions which allow a natural physical interpretation of the relaxation times. Furthermore, our theory nicely gives the explicit forms of the distribution function and the thirteen hydrodynamic variables in terms of the linearized collision operator, which in turn clearly suggest the proper ansatz forms of them to be adopted in the method of moments.
(3+1)-dimensional framework for leading-order non conformal anisotropic hydrodynamics
Leonardo Tinti
2015-05-24T23:59:59.000Z
In this work I develop a new framework for anisotropic hydrodynamics that generalizes the leading order of the hydrodynamic expansion to the full (3+1)-dimensional anisotropic massive case. Following previous works, my considerations are based on the Boltzmann kinetic equation with the collisional term treated in the relaxation time approximation. The momentum anisotropy is included explicitly in the leading term, allowing for a large difference between the longitudinal and transverse pressures as well as for non trivial transverse dynamics. Energy and momentum conservation is expressed by the first moment of the Boltzmann equation. The system of equations is closed by using the zeroth and second moments of the Boltzmann equation. The close-to-equilibrium matching with second-order viscous hydrodynamics is demonstrated. In particular, I show that the coupling between shear and bulk pressure corrections, recently proved to be important for an accurate description of momentum anisotropy and bulk viscous dynamics, does not vanish in the close-to-equilibrium limit.
Experimental and computational studies of hydrodynamics in three-phase and two-phase fluidized beds
Bahary, M.
1994-12-01T23:59:59.000Z
The objective of the present study was to investigate the hydrodynamics of three-phase fluidized beds, their rheology, and experimentally verify a predictive three fluid hydrodynamic model developed at the Illinois Institute of Technology, Chicago. The recent reviews show that there exist no such models in the literature. The IIT hydrodynamic model computes the phase velocities and the volume fractions of gas, liquid, and particulate phases. Model verification involves a comparison of these computed velocities and volume fractions to experimental values. In this thesis, a three fluid model is presented. The input into the model can be particulate viscosities either measured with a Brookfield viscometer or derived using the mathematical techniques of kinetic theory of granular flows pioneered by Savage and others. The computer simulation of a three-phase fluidized bed in an asymmetric mode qualitatively predicts the gas, liquid and solid hold-ups (volume fractions) and flow patterns in the industrially important churn-turbulent (bubbly coalesced) regimes. The computations in a fluidized bed with a symmetric distributor incorrectly showed no bubble coalescence. A combination of X-ray and {gamma}-ray densitometers was used to measure the solids and the liquid volume fractions in a two dimensional bed in the bubble coalesced regime. There is a good agreement between the theory for an asymmetric distributor and the experiments.
Hydrodynamic flow in the vicinity of a nanopore induced by an applied voltage
Mao Mao; Sandip Ghosal; Guohui Hu
2013-05-16T23:59:59.000Z
Continuum simulation is employed to study ion transport and fluid flow through a nanopore in a solid-state membrane under an applied potential drop. Results show the existence of concentration polarization layers on the surfaces of the membrane. The nonuniformity of the ionic distribution gives rise to an electric pressure that drives vortical motion in the fluid. There is also a net hydrodynamic flow through the nanopore due to an asymmetry induced by the membrane surface charge. The qualitative behavior is similar to that observed in a previous study using molecular dynamic simulations. The current--voltage characteristics show some nonlinear features but are not greatly affected by the hydrodynamic flow in the parameter regime studied. In the limit of thin Debye layers, the electric resistance of the system can be characterized using an equivalent circuit with lumped parameters. Generation of vorticity can be understood qualitatively from elementary considerations of the Maxwell stresses. However, the flow strength is a strongly nonlinear function of the applied field. Combination of electrophoretic and hydrodynamic effects can lead to ion selectivity in terms of valences and this could have some practical applications in separations.
Jeremiah W. Murphy; Adam Burrows
2008-07-09T23:59:59.000Z
In this paper, we describe a new hydrodynamics code for 1D and 2D astrophysical simulations, BETHE-hydro, that uses time-dependent, arbitrary, unstructured grids. The core of the hydrodynamics algorithm is an arbitrary Lagrangian-Eulerian (ALE) approach, in which the gradient and divergence operators are made compatible using the support-operator method. We present 1D and 2D gravity solvers that are finite differenced using the support-operator technique, and the resulting system of linear equations are solved using the tridiagonal method for 1D simulations and an iterative multigrid-preconditioned conjugate-gradient method for 2D simulations. Rotational terms are included for 2D calculations using cylindrical coordinates. We document an incompatibility between a subcell pressure algorithm to suppress hourglass motions and the subcell remapping algorithm and present a modified subcell pressure scheme that avoids this problem. Strengths of this code include a straightforward structure, enabling simple inclusion of additional physics packages, the ability to use a general equation of state, and most importantly, the ability to solve self-gravitating hydrodynamic flows on time-dependent, arbitrary grids. In what follows, we describe in detail the numerical techniques employed and, with a large suite of tests, demonstrate that BETHE-hydro finds accurate solutions with 2$^{nd}$-order convergence.
V. Yu. Naboka; S. V. Akkelin; Iu. A. Karpenko; Yu. M. Sinyukov
2015-01-14T23:59:59.000Z
A key ingredient of hydrodynamical modeling of relativistic heavy ion collisions is thermal initial conditions, an input that is the consequence of a pre-thermal dynamics which is not completely understood yet. In the paper we employ a recently developed energy-momentum transport model of the pre-thermal stage to study influence of the alternative initial states in nucleus-nucleus collisions on flow and energy density distributions of the matter at the starting time of hydrodynamics. In particular, the dependence of the results on isotropic and anisotropic initial states is analyzed. It is found that at the thermalization time the transverse flow is larger and the maximal energy density is higher for the longitudinally squeezed initial momentum distributions. The results are also sensitive to the relaxation time parameter, equation of state at the thermalization time, and transverse profile of initial energy density distribution: Gaussian approximation, Glauber Monte Carlo profiles, etc. Also, test results ensure that the numerical code based on the energy-momentum transport model is capable of providing both averaged and fluctuating initial conditions for the hydrodynamic simulations of relativistic nuclear collisions.
Yang, Zhaoqing; Liu, Hedong; Khangaonkar, Tarang P.
2006-08-03T23:59:59.000Z
The Skagit River is the largest river in the Puget Sound estuarine system. It discharges about 39% of total sediment and more than 20% of freshwater into Puget Sound. The Skagit River delta provides rich estuarine and freshwater habitats for salmon and many other wildlife species. Over the past 150 years, economic development in the Skagit River delta has resulted in significant losses of wildlife habitat, particularly due to construction of dikes. Diked portion of the delta is known as Fir Island where irrigation practices for agriculture land over the last century has resulted in land subsidence. This has also caused reduced efficiency of drainage network and impeded fish passages through the area. In this study, a three-dimensional tidal circulation model was developed for the Skagit River delta to assist estuarine restoration in the Fir Island area. The hydrodynamic model used in the study is the Finite Volume Coastal Ocean Model (FVCOM). The hydrodynamic model was calibrated using field data collected from the study area specifically for the model development. Wetting and drying processes in the estuarine delta are simulated in the hydrodynamic model. The calibrated model was applied to simulate different restoration alternatives and provide guidance for estuarine restoration and management. Specifically, the model was used to help select and design configurations that would improve the supply of sediment and freshwater to the mudflats and tidal marsh areas outside of diked regions and then improve the estuarine habitats for salmon migration.
Puget Sound Dissolved Oxygen Modeling Study: Development of an Intermediate-Scale Hydrodynamic Model
Yang, Zhaoqing; Khangaonkar, Tarang; Labiosa, Rochelle G.; Kim, Taeyun
2010-11-30T23:59:59.000Z
The Washington State Department of Ecology contracted with Pacific Northwest National Laboratory to develop an intermediate-scale hydrodynamic and water quality model to study dissolved oxygen and nutrient dynamics in Puget Sound and to help define potential Puget Sound-wide nutrient management strategies and decisions. Specifically, the project is expected to help determine 1) if current and potential future nitrogen loadings from point and non-point sources are significantly impairing water quality at a large scale and 2) what level of nutrient reductions are necessary to reduce or dominate human impacts to dissolved oxygen levels in the sensitive areas. In this study, an intermediate-scale hydrodynamic model of Puget Sound was developed to simulate the hydrodynamics of Puget Sound and the Northwest Straits for the year 2006. The model was constructed using the unstructured Finite Volume Coastal Ocean Model. The overall model grid resolution within Puget Sound in its present configuration is about 880 m. The model was driven by tides, river inflows, and meteorological forcing (wind and net heat flux) and simulated tidal circulations, temperature, and salinity distributions in Puget Sound. The model was validated against observed data of water surface elevation, velocity, temperature, and salinity at various stations within the study domain. Model validation indicated that the model simulates tidal elevations and currents in Puget Sound well and reproduces the general patterns of the temperature and salinity distributions.
Multigroup radiation hydrodynamics with flux-limited diffusion and adaptive mesh refinement
González, Matthias; Commerçon, Benoît; Masson, Jacques
2015-01-01T23:59:59.000Z
Radiative transfer plays a key role in the star formation process. Due to a high computational cost, radiation-hydrodynamics simulations performed up to now have mainly been carried out in the grey approximation. In recent years, multi-frequency radiation-hydrodynamics models have started to emerge, in an attempt to better account for the large variations of opacities as a function of frequency. We wish to develop an efficient multigroup algorithm for the adaptive mesh refinement code RAMSES which is suited to heavy proto-stellar collapse calculations. Due to prohibitive timestep constraints of an explicit radiative transfer method, we constructed a time-implicit solver based on a stabilised bi-conjugate gradient algorithm, and implemented it in RAMSES under the flux-limited diffusion approximation. We present a series of tests which demonstrate the high performance of our scheme in dealing with frequency-dependent radiation-hydrodynamic flows. We also present a preliminary simulation of a three-dimensional p...
The core helium flash revisited: I. One and two-dimensional hydrodynamic simulations
M. Mocak; E. Mueller; A. Weiss; K. Kifonidis
2008-05-09T23:59:59.000Z
We investigate the hydrodynamics of the core helium flash near its peak. Past research concerned with the dynamics of this event is inconclusive. However, the most recent multidimensional hydrodynamic studies suggest a quiescent behavior and seem to rule out an explosive scenario. Previous work indicated, that depending on initial conditions, employed turbulence models, grid resolution, and dimensionality of the simulation, the core helium flash leads either to the disruption of a low-mass star or to a quiescent quasi-hydrostatic evolution. We try to clarify this issue by simulating the evolution with advanced numerical methods and detailed microphysics. Assuming spherical or axial symmetry, we simulate the evolution of the helium core of a $1.25 M_{\\odot}$ star with a metallicity Z=0.02 during the core helium flash at its peak with a grid-based hydrodynamics code. We find that the core helium flash neither rips the star apart, nor that it significantly alters its structure, as convection plays a crucial role in keeping the star in hydrostatic equilibrium. In addition, our simulations show the presence of overshooting, which implies new predictions concerning mixing of chemical species in red giants.
Linn, Anne Marie
1985-01-01T23:59:59.000Z
processes. The burial history of the sandstones includes compaction of sediments and development of quartz over growths, precipitation of clays and cements, decementation, a second precipitation of clays and cements, partial dissolution of cements...) noted that the Wheat field has a tilted oil/water contact implying that hydrodynamic flow is present. The influence of hydrodynamic flow on oil entrapment was determined from the analysis of subsurface pressur es derived from drill stem tests...
Auerbach, Scott M.
Modeling Proton Jumps in HY Zeolite: Effects of Acid Site Heterogeneity Usha Viswanathan, Justin T; In Final Form: September 21, 2007 We have computed the total mean rate coefficient for proton transfer in bare H-Y zeolite, for comparison with NMR experiments and previous calculations. We computed proton
Karsch,F.; Kharzeev, D.; Molnar, K.; Petreczky, P.; Teaney, D.
2008-04-21T23:59:59.000Z
The interpretation of relativistic heavy-ion collisions at RHIC energies with thermal concepts is largely based on the relative success of ideal (nondissipative) hydrodynamics. This approach can describe basic observables at RHIC, such as particle spectra and momentum anisotropies, fairly well. On the other hand, recent theoretical efforts indicate that dissipation can play a significant role. Ideally viscous hydrodynamic simulations would extract, if not only the equation of state, but also transport coefficients from RHIC data. There has been a lot of progress with solving relativistic viscous hydrodynamics. There are already large uncertainties in ideal hydrodynamics calculations, e.g., uncertainties associated with initial conditions, freezeout, and the simplified equations of state typically utilized. One of the most sensitive observables to the equation of state is the baryon momentum anisotropy, which is also affected by freezeout assumptions. Up-to-date results from lattice quantum chromodynamics on the transition temperature and equation of state with realistic quark masses are currently available. However, these have not yet been incorporated into the hydrodynamic calculations. Therefore, the RBRC workshop 'Hydrodynamics in Heavy Ion Collisions and QCD Equation of State' aimed at getting a better understanding of the theoretical frameworks for dissipation and near-equilibrium dynamics in heavy-ion collisions. The topics discussed during the workshop included techniques to solve the dynamical equations and examine the role of initial conditions and decoupling, as well as the role of the equation of state and transport coefficients in current simulations.
2000 Astronomy Department, University of Texas at Austin Full Of Hot Air?
Hemenway, Mary Kay
Â©2000 Astronomy Department, University of Texas at Austin Full Of Hot Air? Introduction Light has standing by a pool, the medium is air. If you are looking at the Moon from under water after you jump into the pool, the mediums are both air and water. The Moon would appear dif- ferent from underwater because
Pennsylvania State University | Open Energy Information
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are being directedAnnual SiteofEvaluatingGroup |JilinLuOpenNorthOlympiaAnalysis)PearlPennsylvania State University Jump
James Biggs; Mary Mullen; Kathryn Bennett
1999-11-01T23:59:59.000Z
The New Mexico meadow jumping mouse (Zapus hudsonius luteus) is currently listed as a state threatened species in New Mexico and has been identified as potentially occurring within the Los Alamos National Laboratory (LANL) boundary. We describe the development of a model to identify and rank habitat at LANL that may be suitable for occupation by this species. The model calculates a habitat suitability ranking (HSR) based on total plant cover, plant species composition, total number of plant species, and plant height. Input data for the model is based on the measurement of these variables at known locations where this species has been found within the Jemez Mountains. Model development included the selection of habitat variables, developing a probability distribution for each variable, and applying weights to each variable based on their overall importance in defining the suitability of the habitat. The habitat variables (HV) include plant cover (HV1), grass/forb cover (HV2), plant height (HV3), number of forbs (HV4), number of grasses (HV5), and sedge/rush cover (HV6). Once the HVs were selected, probability values were calculated for each. Each variable was then assigned a ''weighting factor'' to reflect the variables' importance relative to one another with respect to contribution to quality of habitat. The least important variable, sedge/rush cover, was assigned a weight factor of ''1'' with increasing values assigned to each remaining variable as follows: number of forbs = 3, number of grasses = 3, plant height = 5, grass/forb cover = 6, and total plant cover = 7. Based on the probability values and weighting factors, a HSR is calculated as follows: HSR = (P{sub HV1}(7) + P{sub HV2}(6) + P{sub HV3}(5) + P{sub HV4}(3) + P{sub HV5}(3) + P{sub HV6}(1)). Once calculated, the HSR values are placed into one of four habitat categorical groupings by which management strategies are applied.
When did vacuum energy of the Universe become cosmological constant?
V. Burdyuzha
2007-12-29T23:59:59.000Z
A quark-gluon phase transition in the Universe is researched after which vacuum (dark) energy has hardened and become cosmological constant. Before this a vacuum component of the Universe was changing by jumps during phase transitions since vacuum condensates of quantum fields carried a negative contribution in its positive density energy. This quintessence period of the Universe life took place during the first parts of a second when our Universe was losing high symmetry. Using Zel'dovich's formula the modern value of vacuum energy is also calculated. It is shown that a quantum chromodynamical vacuum which is characterized by pseudogoldstone bosons existed definitely when temperature of the Universe was T~150 MeV. Therefore there is a large probability that dark energy is vacuum energy.
Dynamics of suspensions of hydrodynamically structured particles: Analytic theory and experiment
Jonas Riest; Thomas Eckert; Walter Richtering; Gerhard Nägele
2015-01-12T23:59:59.000Z
We present an easy-to-use analytic toolbox for the calculation of short-time transport properties of concentrated suspensions of spherical colloidal particles with internal hydrodynamic structure, and direct interactions described by a hard-core or soft Hertz pair potential. The considered dynamic properties include self-diffusion and sedimentation coefficients, the wavenumber-dependent diffusion function determined in dynamic scattering experiments, and the high-frequency shear viscosity. The toolbox is based on the hydrodynamic radius model (HRM) wherein the internal particle structure is mapped on a hydrodynamic radius parameter for unchanged direct interactions, and on an existing simulation data base for solvent-permeable and spherical annulus particles. Useful scaling relations for the diffusion function and self-diffusion coefficient, known to be valid for hard-core interaction, are shown to apply also for soft pair potentials. We further discuss extensions of the toolbox to long-time transport properties including the low-shear zero-frequency viscosity and the long-time self-diffusion coefficient. The versatility of the toolbox is demonstrated by the analysis of a previous light scattering study of suspensions of non-ionic PNiPAM microgels [Eckert et al., J. Chem. Phys., 2008, 129, 124902] in which a detailed theoretical analysis of the dynamic data was left as an open task. By the comparison with Hertz potential based calculations, we show that the experimental data are consistently and accurately described using the Verlet-Weis corrected Percus-Yevick structure factor as input, and for a solvent penetration length equal to three percent of the excluded volume radius. This small solvent permeability of the microgel particles has a significant dynamic effect at larger concentrations.
Iterative linear solvers in a 2D radiation-hydrodynamics code: Methods and performance
Baldwin, C.; Brown, P.N.; Falgout, R.; Graziani, F.; Jones, J.
1999-09-01T23:59:59.000Z
Computer codes containing both hydrodynamics and radiation play a central role in simulating both astrophysical and inertial confinement fusion (ICF) phenomena. A crucial aspect of these codes is that they require an implicit solution of the radiation diffusion equations. The authors present in this paper the results of a comparison of five different linear solvers on a range of complex radiation and radiation-hydrodynamics problems. The linear solvers used are diagonally scaled conjugate gradient, GMRES with incomplete LU preconditioning, conjugate gradient with incomplete Cholesky preconditioning, multigrid, and multigrid-preconditioned conjugate gradient. These problems involve shock propagation, opacities varying over 5--6 orders of magnitude, tabular equations of state, and dynamic ALE (Arbitrary Lagrangian Eulerian) meshes. They perform a problem size scalability study by comparing linear solver performance over a wide range of problem sizes from 1,000 to 100,000 zones. The fundamental question they address in this paper is: Is it more efficient to invert the matrix in many inexpensive steps (like diagonally scaled conjugate gradient) or in fewer expensive steps (like multigrid)? In addition, what is the answer to this question as a function of problem size and is the answer problem dependent? They find that the diagonally scaled conjugate gradient method performs poorly with the growth of problem size, increasing in both iteration count and overall CPU time with the size of the problem and also increasing for larger time steps. For all problems considered, the multigrid algorithms scale almost perfectly (i.e., the iteration count is approximately independent of problem size and problem time step). For pure radiation flow problems (i.e., no hydrodynamics), they see speedups in CPU time of factors of {approx}15--30 for the largest problems, when comparing the multigrid solvers relative to diagonal scaled conjugate gradient.
Fleenor, William E.; Bombardelli, Fabian
2013-01-01T23:59:59.000Z
Hydrodynamic and Salinity Transport Modeling of the Sacramento–San Joaquinhydrodynamic and salinity transport mod- eling of the Sacramento–San Joaquin
Zgoubi-ing AGS : spin motion with snakes and jump-quads,G? = 43.5 through G? = 46.5 and beyond
Meot, F.; Ahrens, L.; Glenn, J.; Huang, H.; Luccio, A.; MacKay, W. W.; Roser, T.; Tsoupas, N.
2009-10-01T23:59:59.000Z
This Note reports on the first, and successful, simulations of particle and spin dynamics in the AGS in presence of the two helical snakes and of the tune-jump quadrupoles, using the ray-tracing code Zgoubi. It includes DA tracking in the absence or in the presence of the two helical snakes, simulation of particle and spin motion in the snakes using their magnetic field maps, spin flipping at integer resonances in the 36+Qy depolarizing resonance region, with and without tune-jump quadrupole gymnastics. It also includes details on the setting-up of Zgoubi input data files and on the various numerical methods of concern in and available from Zgoubi.
Viscous Flows and Conditions for Existence of Shocks in Relativistic Magnetic Hydrodynamics
V. I. Zhdanov; P. V. Tytarenko; M. S. Borshch
2004-07-23T23:59:59.000Z
We present a criterion for a shock wave existence in relativistic magnetic hydrodynamics with an arbitrary (possibly non-convex) equation of state. The criterion has the form of algebraic inequality that involves equation of state of the fluid; it singles out the physical solutions and it can be easily checked for any discontinuity satisfying concervation laws. The method of proof uses introduction of small viscosity into the coupled set of equations of motion of ideal relativistic fluid with infinite conductivity and Maxwell equations.
Simulating Rayleigh-Taylor (RT) instability using PPM hydrodynamics @scale on Roadrunner (u)
Woodward, Paul R [Los Alamos National Laboratory; Dimonte, Guy [Los Alamos National Laboratory; Rockefeller, Gabriel M [Los Alamos National Laboratory; Fryer, Christopher L [Los Alamos National Laboratory; Dimonte, Guy [Los Alamos National Laboratory; Dai, W [Los Alamos National Laboratory; Kares, R. J. [Los Alamos National Laboratory
2011-01-05T23:59:59.000Z
The effect of initial conditions on the self-similar growth of the RT instability is investigated using a hydrodynamics code based on the piecewise-parabolic-method (PPM). The PPM code was converted to the hybrid architecture of Roadrunner in order to perform the simulations at extremely high speed and spatial resolution. This paper describes the code conversion to the Cell processor, the scaling studies to 12 CU's on Roadrunner and results on the dependence of the RT growth rate on initial conditions. The relevance of the Roadrunner implementation of this PPM code to other existing and anticipated computer architectures is also discussed.
Dense granular flow around a penetrating object: Experiments and hydrodynamic model
Antoine Seguin; Yann Bertho; Philippe Gondret; Jerome Crassous
2011-06-24T23:59:59.000Z
We present in this Letter experimental results on the bidimensional flow field around a cylinder penetrating into dense granular matter together with drag force measurements. A hydrodynamic model based on extended kinetic theory for dense granular flow reproduces well the flow localization close to the cylinder and the corresponding scalings of the drag force, which is found to not depend on velocity, but linearly on the pressure and on the cylinder diameter and weakly on the grain size. Such a regime is found to be valid at a low enough "granular" Reynolds number.
Hydrodynamic radial and elliptic flow in heavy-ion collisions from AGS to LHC energies
Gregory Kestin; Ulrich W Heinz
2008-11-28T23:59:59.000Z
Using ideal relativistic hydrodynamics in 2+1 dimensions, we study the collision energy dependence of radial and elliptic flow, of the emitted hadron spectra, and of the transverse momentum dependence of several hadronic particle ratios, covering the range from Alternating Gradient Synchrotron (AGS) to Large Hadron Collider (LHC) energies. These calculations establish an ideal fluid dynamic baseline that can be used to assess non-equilibrium features manifest in future LHC heavy-ion experiments. Contrary to earlier suggestions we find that a saturation and even decrease of the differential elliptic flow v_2(p_T) with increasing collision energy cannot be unambiguously associated with the QCD phase transition.
Transport coefficients of off-lattice mesoscale-hydrodynamics simulation techniques
Hiroshi Noguchi; Gerhard Gompper
2008-04-14T23:59:59.000Z
The viscosity and self-diffusion constant of particle-based mesoscale hydrodynamic methods, multi-particle collision dynamics (MPC) and dissipative particle dynamics (DPD), are investigated, both with and without angular-momentum conservation. Analytical results are derived for fluids with an ideal-gas equation of state and a finite-time-step dynamics, and compared with simulation data. In particular, the viscosity is derived in a general form for all variants of the MPC method. In general, very good agreement between theory and simulations is obtained.
Chaudhuri, A K
2012-01-01T23:59:59.000Z
In nucleon-nucleon collisions, charged particle's multiplicity fluctuates. We have studied the effect of multiplicity fluctuation on flow harmonics in nucleus-nucleus collision in event-by-event hydrodynamics. Assuming that the charged particle's multiplicity fluctuations are governed by the negative binomial distribution, the Monte-Carlo Glauber model of initial condition is generalised to include the fluctuations. Explicit simulations with the generalised Monte-Carlo Glauber model initial conditions indicate that the multiplicity fluctuations do not have large effect on the flow harmonics.
A. K. Chaudhuri
2013-03-19T23:59:59.000Z
In nucleon-nucleon collisions, charged particle's multiplicity fluctuates. We have studied the effect of multiplicity fluctuation on flow harmonics in nucleus-nucleus collision in event-by-event hydrodynamics. Assuming that the charged particle's multiplicity fluctuations are governed by the negative binomial distribution, the Monte-Carlo Glauber model of initial condition is generalised to include the fluctuations. Explicit simulations with the generalised Monte-Carlo Glauber model initial conditions indicate that the multiplicity fluctuations do not have large effect on the flow harmonics.
Knudsen-Hydrodynamic Crossover in Liquid 3He in High Porosity Aerogel
Takeuchi, H; Nagai, K; Choi, H C; Moon, B H; Masuhara, N; Meisel, M W; Lee, Y; Mulders, N
2012-01-01T23:59:59.000Z
We present a combined experimental and theoretical study of the drag force acting on a high porosity aerogel immersed in liquid ${}^3$He and its effect on sound propagation. The drag force is characterized by the Knudsen number, which is defined as the ratio of the quasiparticle mean free path to the radius of an aerogel strand. Evidence of the Knudsen-hydrodynamic crossover is clearly demonstrated by a drastic change in the temperature dependence of ultrasound attenuation in 98% porosity aerogel. Our theoretical analysis shows that the frictional sound damping caused by the drag force is governed by distinct laws in the two regimes, providing excellent agreement with the experimental observation.
Hydrodynamic Relaxation of an Electron Plasma to a Near-Maximum Entropy State
Rodgers, D. J.; Servidio, S.; Matthaeus, W. H.; Mitchell, T. B.; Aziz, T. [Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716 (United States); Montgomery, D. C. [Department of Physics and Astronomy, Dartmouth College, Hanover, New Hampshire 03755 (United States)
2009-06-19T23:59:59.000Z
Dynamical relaxation of a pure electron plasma in a Malmberg-Penning trap is studied, comparing experiments, numerical simulations and statistical theories of weakly dissipative two-dimensional (2D) turbulence. Simulations confirm that the dynamics are approximated well by a 2D hydrodynamic model. Statistical analysis favors a theoretical picture of relaxation to a near-maximum entropy state with constrained energy, circulation, and angular momentum. This provides evidence that 2D electron fluid relaxation in a turbulent regime is governed by principles of maximum entropy.
Khan, Shabbir A
2013-01-01T23:59:59.000Z
Quantum plasma physics is a rapidly evolving research field with a very inter-disciplinary scope of potential applications, ranging from nano-scale science in condensed matter to the vast scales of astrophysical objects. The theoretical description of quantum plasmas relies on various approaches, microscopic or macroscopic, some of which have obvious relation to classical plasma models. The appropriate model should, in principle, incorporate the quantum mechanical effects such as diffraction, spin statistics and correlations, operative on the relevant scales. However, first-principle approaches such as quantum Monte Carlo and density functional theory or quantum-statistical methods such as quantum kinetic theory or non-equilibrium Green's functions require substantial theoretical and computational efforts. Therefore, for selected problems, alternative simpler methods have been put forward. In particular, the collective behavior of many-body systems is usually described within a self-consistent scheme of parti...
Goncharov, V. N.; Sangster, T. C.; Betti, R.; Boehly, T. R.; Bonino, M. J.; Collins, T. J. B.; Craxton, R. S.; Delettrez, J. A.; Edgell, D. H.; Epstein, R.; Follett, R. K.; Forrest, C. J.; Froula, D. H.; Glebov, V. Yu.; Harding, D. R.; Henchen, R. J.; Hu, S. X.; Igumenshchev, I. V.; Janezic, R.; Kelly, J. H. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States); and others
2014-05-15T23:59:59.000Z
Reaching ignition in direct-drive (DD) inertial confinement fusion implosions requires achieving central pressures in excess of 100 Gbar. The OMEGA laser system [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)] is used to study the physics of implosions that are hydrodynamically equivalent to the ignition designs on the National Ignition Facility (NIF) [J. A. Paisner et al., Laser Focus World 30, 75 (1994)]. It is shown that the highest hot-spot pressures (up to 40 Gbar) are achieved in target designs with a fuel adiabat of ? ? 4, an implosion velocity of 3.8?×?10{sup 7}?cm/s, and a laser intensity of ?10{sup 15}?W/cm{sup 2}. These moderate-adiabat implosions are well understood using two-dimensional hydrocode simulations. The performance of lower-adiabat implosions is significantly degraded relative to code predictions, a common feature between DD implosions on OMEGA and indirect-drive cryogenic implosions on the NIF. Simplified theoretical models are developed to gain physical understanding of the implosion dynamics that dictate the target performance. These models indicate that degradations in the shell density and integrity (caused by hydrodynamic instabilities during the target acceleration) coupled with hydrodynamics at stagnation are the main failure mechanisms in low-adiabat designs. To demonstrate ignition hydrodynamic equivalence in cryogenic implosions on OMEGA, the target-design robustness to hydrodynamic instability growth must be improved by reducing laser-coupling losses caused by cross beam energy transfer.
University Murdoch University The University of Newcastle Biography for GLOVER, Professor Barney Vice Chancellor, Charles Darwin University Professor Barney Glover is Vice-Chancellor of Charles Darwin University
University Profile University of Canterbury
Hickman, Mark
University Profile 2007Â2009 #12;University of Canterbury PROFILE 2007 - 2009 Submitted to the Tertiary Education Commission, 31 October, 2006 #12;University of Canterbury Profile 2007-2009 Page 2 of 64 #12;Contents Page Profile Purpose and Structure 4 Part A: Strategic Direction 5 Part B: Key Strategic
Kadioglu, Samet Y. [Multiphysics Methods Group, Reactor Physics Analysis and Design, Idaho National Laboratory, P.O. Box 1625, MS 3840, Idaho Falls, ID 83415 (United States)], E-mail: Samet.Kadioglu@inl.gov; Knoll, Dana A. [Multiphysics Methods Group, Reactor Physics Analysis and Design, Idaho National Laboratory, P.O. Box 1625, MS 3840, Idaho Falls, ID 83415 (United States)], E-mail: dana.knoll@inl.gov
2010-05-01T23:59:59.000Z
We present a fully second order implicit/explicit time integration technique for solving hydrodynamics coupled with nonlinear heat conduction problems. The idea is to hybridize an implicit and an explicit discretization in such a way to achieve second order time convergent calculations. In this scope, the hydrodynamics equations are discretized explicitly making use of the capability of well-understood explicit schemes. On the other hand, the nonlinear heat conduction is solved implicitly. Such methods are often referred to as IMEX methods. The Jacobian-Free Newton Krylov (JFNK) method (e.g. ) is applied to the problem in such a way as to render a nonlinearly iterated IMEX method. We solve three test problems in order to validate the numerical order of the scheme. For each test, we established second order time convergence. We support these numerical results with a modified equation analysis (MEA). The set of equations studied here constitute a base model for radiation hydrodynamics.
Rose, K A; Hoffman, B; Saintillan, D; Shaqfeh, E G; Santiago, J G
2008-05-05T23:59:59.000Z
We present a theoretical and experimental study of the role of hydrodynamic interactions on the motion and dispersion of metal rod-like particles in the presence of an externally applied electric field. In these systems, the electric field polarizes the particles and induces an electroosmosis flow relative to the surface of each particle. The simulations include the effect of the gravitational body force, buoyancy, far-field hydrodynamic interactions, near-field lubrication forces, and electric field interactions. The particles in the simulations and experiments were observed to experience repeated pairing interactions in which they come together axially with their ends approaching each other, slide past one another until their centers approach, and then push apart. These interactions were confirmed in measurements of particle orientations and velocities, pair distribution functions, and net dispersion of the suspension. For large electric fields, the pair distribution functions show accumulation and depletion regions consistent with many pairing events. For particle concentrations of 1e8 particles/mL and higher, dispersion within the suspension dramatically increases with increased field strength.
Selective evaporation of focusing fluid in two-fluid hydrodynamic print head.
Keicher, David M.; Cook, Adam W.
2014-09-01T23:59:59.000Z
The work performed in this project has demonstrated the feasibility to use hydrodynamic focusing of two fluid steams to create a novel micro printing technology for electronics and other high performance applications. Initial efforts focused solely on selective evaporation of the sheath fluid from print stream provided insight in developing a unique print head geometry allowing excess sheath fluid to be separated from the print flow stream for recycling/reuse. Fluid flow models suggest that more than 81 percent of the sheath fluid can be removed without affecting the print stream. Further development and optimization is required to demonstrate this capability in operation. Print results using two-fluid hydrodynamic focusing yielded a 30 micrometers wide by 0.5 micrometers tall line that suggests that the cross-section of the printed feature from the print head was approximately 2 micrometers in diameter. Printing results also demonstrated that complete removal of the sheath fluid is not necessary for all material systems. The two-fluid printing technology could enable printing of insulated conductors and clad optical interconnects. Further development of this concept should be pursued.
Application of a fiber optic probe to the hydrodynamic study of an industrial fluidized bed furnace
Saberi, B.; Shakourzadeh, K. [Technical Univ. of Compiegne (France); Militzer, J. [Technical Univ. of Nova Scotia, Halifax, Nova Scotia (Canada)
1997-12-31T23:59:59.000Z
A fiber optic probe technique is used to establish the hydrodynamic characteristics of an industrial scale (0.9 m internal diameter and 2.5 m tall) bubbling fluidized bed. This measurement technique allows for the bubbling phenomenon to be studied locally. Bubble parameters such as size, velocity and frequency can be measured with an adequate accuracy. This, however, is not a straight forward procedure, since among other things the shape of the bubble and the position at which fiber intercepts the bubble are unknown. This requires a statistical treatment of the data and the use of a correction factor. A geometrical and statistical analysis of the bubble/probe interactions shows that the correction factor is approximately unitary and thus the bubble size distribution can be obtained directly from the statistical treatment of the results of relatively large number of series of measurements. In addition, sampling rate and sample duration have to be determined as a function of the bubble size and velocity. Several combinations of sampling time and sampling rate have been tested allowing for the best combination of these parameters to be determined. After treatment of the acquired signals, the mean bubble size and velocity were calculated. The results obtained were compared to the measured expansion of the bed and the overall gas flow rate. This confirmed the accuracy of the measurements and the usefulness of this technique to establish the hydrodynamics of bubbling fluidized beds.
Hydrodynamic Effects in the Symmetron and $f(R)$-gravity Models
Amir Hammami; Claudio Llinares; David F. Mota; Hans A. Winther
2015-03-06T23:59:59.000Z
In this paper we present the first results from implementing two scalar-tensor modified gravity theories, the symmetron and the Hu-Sawicki $f(R)$-gravity model, into a hydrodynamic N-body code with dark matter particles and a baryonic ideal gas. The study is a continuation of previous work where the symmetron and $f(R)$ have been successfully implemented in the RAMSES code, but for dark matter only. By running simulations, we show that the deviation from $\\Lambda$CDM in these models for the gas density profiles are significantly lower than the dark matter equivalents. When it comes to the matter power-spectrum we find that hydrodynamic simulations agree very well with dark matter only simulations as long as we consider scales larger than $k\\sim 0.5$ h/Mpc. In general the effects of modified gravity on the baryonic gas is found to not always mirror the effects it has on the dark matter. The largest signature is found when considering temperature profiles. We find that the gas temperatures in the modified gravity model studied here show deviations, when compared to $\\Lambda$CDM, that can be a factor of a few larger than the deviations found in density profiles and power spectra.
M. Hakan Erkut; Dimitrios Psaltis; M. Ali Alpar
2008-07-28T23:59:59.000Z
The observational characteristics of quasi-periodic oscillations (QPOs) from accreting neutron stars strongly indicate the oscillatory modes in the innermost regions of accretion disks as a likely source of the QPOs. The inner regions of accretion disks around neutron stars can harbor very high frequency modes related to the radial epicyclic frequency $\\kappa $. The degeneracy of $\\kappa $ with the orbital frequency $\\Omega $ is removed in a non-Keplerian boundary or transition zone near the magnetopause between the disk and the compact object. We show, by analyzing the global hydrodynamic modes of long wavelength in the boundary layers of viscous accretion disks, that the fastest growing mode frequencies are associated with frequency bands around $\\kappa $ and $\\kappa \\pm \\Omega $. The maximum growth rates are achieved near the radius where the orbital frequency $\\Omega $ is maximum. The global hydrodynamic parameters such as the surface density profile and the radial drift velocity determine which modes of free oscillations will grow at a given particular radius in the boundary layer. In accordance with the peak separation between kHz QPOs observed in neutron-star sources, the difference frequency between two consecutive bands of the fastest growing modes is always related to the spin frequency of the neutron star. This is a natural outcome of the boundary condition imposed by the rotating magnetosphere on the boundary region of the inner disk.
Jet Propagation and Mach-Cone Formation in (3+1)-dimensional Ideal Hydrodynamics
Barbara Betz
2009-10-20T23:59:59.000Z
This thesis investigates the jet-medium interactions in a Quark-Gluon Plasma using a hydrodynamical model. It deals with the creation of Mach cones which are supposed to exhibit a characteristic structure in the measured angular particle distributions allowing for direct conclusions about the Equation of State and in particular about the speed of sound of the medium. Several different scenarios of jet energy loss are examined and different mechanisms of energy and momentum loss are analyzed, ranging from weak interactions (based on calculations from perturbative Quantum Chromodynamics, pQCD) to strong interactions (formulated using the Anti-de-Sitter/Conformal Field Theory Correspondence, AdS/CFT). Though they result in different angular particle correlations which could in principle allow to distinguish the underlying processes, it is shown that the characteristic structure observed in experimental data can be obtained due to the different contributions of several possible jet trajectories through an expanding medium. Such a structure cannot directly be connected to the Equation of State. In this context, the impact of a strong flow created behind the jet (the diffusion wake) is examined which is common to almost all jet deposition scenarios. Besides that, the transport equations for dissipative hydrodynamics are discussed which are fundamental for any numerical computation of viscous effects in a Quark-Gluon Plasma.
Hydrodynamic instability growth and mix experiments at the National Ignition Facility
Smalyuk, V. A.; Barrios, M.; Caggiano, J. A.; Casey, D. T.; Cerjan, C. J.; Clark, D. S.; Edwards, M. J.; Haan, S. W.; Hammel, B. A.; Hamza, A.; Hsing, W. W.; Hurricane, O.; Kroll, J.; Landen, O. L.; Lindl, J. D.; Ma, T.; McNaney, J. M.; Mintz, M.; Parham, T.; Peterson, J. L. [Lawrence Livermore National Laboratory, NIF Directorate, Livermore, California 94550 (United States)] [Lawrence Livermore National Laboratory, NIF Directorate, Livermore, California 94550 (United States); and others
2014-05-15T23:59:59.000Z
Hydrodynamic instability growth and its effects on implosion performance were studied at the National Ignition Facility [G. H. Miller, E. I. Moses, and C. R. Wuest, Opt. Eng. 443, 2841 (2004)]. Implosion performance and mix have been measured at peak compression using plastic shells filled with tritium gas and containing embedded localized carbon-deuterium diagnostic layers in various locations in the ablator. Neutron yield and ion temperature of the deuterium-tritium fusion reactions were used as a measure of shell-gas mix, while neutron yield of the tritium-tritium fusion reaction was used as a measure of implosion performance. The results have indicated that the low-mode hydrodynamic instabilities due to surface roughness were the primary culprits for yield degradation, with atomic ablator-gas mix playing a secondary role. In addition, spherical shells with pre-imposed 2D modulations were used to measure instability growth in the acceleration phase of the implosions. The capsules were imploded using ignition-relevant laser pulses, and ablation-front modulation growth was measured using x-ray radiography for a shell convergence ratio of ?2. The measured growth was in good agreement with that predicted, thus validating simulations for the fastest growing modulations with mode numbers up to 90 in the acceleration phase. Future experiments will be focused on measurements at higher convergence, higher-mode number modulations, and growth occurring during the deceleration phase.
Temperature dependent sound velocity in hydrodynamic equations for relativistic heavy-ion collisions
Mikolaj Chojnacki
2007-09-11T23:59:59.000Z
We analyze the effects of different forms of the sound-velocity function cs(T) on the hydrodynamic evolution of matter formed in the central region of relativistic heavy-ion collisions. At high temperatures (above the critical temperature Tc) the sound velocity is calculated from the recent lattice simulations of QCD, while in the low temperature region it is obtained from the hadron gas model. In the intermediate region we use different interpolations characterized by the values of the sound velocity at the local maximum (at T = 0.4 Tc) and local minimum (at T = Tc). In all considered cases the temperature dependent sound velocity functions yield the entropy density, which is consistent with the lattice QCD simulations at high temperature. Our calculations show that the presence of a distinct minimum of the sound velocity leads to a very long (about 20 fm/c) evolution time of the system, which is not compatible with the recent estimates based on the HBT interferometry. Hence, we conclude that the hydrodynamic description is favored in the case where the cross-over phase transition renders the smooth sound velocity function with a possible shallow minimum at Tc.
Tri Thanh Pham; Burkhard Duenweg; J. Ravi Prakash
2010-10-29T23:59:59.000Z
We investigate the dynamics of the collapse of a single copolymer chain, when the solvent quality is suddenly quenched from good to poor. We employ Brownian dynamics simulations of a bead-spring chain model and incorporate fluctuating hydrodynamic interactions via the Rotne-Prager-Yamakawa tensor. Various copolymer architectures are studied within the framework of a two-letter HP model, where monomers of type H (hydrophobic) attract each other, while all interactions involving P (polar or hydrophilic) monomers are purely repulsive. The hydrodynamic interactions are found to assist the collapse. Furthermore, the chain sequence has a strong influence on the kinetics and on the compactness and energy of the final state. The dynamics is typically characterised by initial rapid cluster formation, followed by coalescence and final rearrangement to form the compact globule. The coalescence stage takes most of the collapse time, and its duration is particularly sensitive to the details of the architecture. Long blocks of type P are identified as the main bottlenecks to find the globular state rapidly.
Hydrodynamic Simulations of Propagating Warps and Bending Waves In Accretion Discs
Richard P. Nelson; John C. B. Papaloizou
1999-07-06T23:59:59.000Z
We present the results of a study of propagating warp or bending waves in accretion discs. Three dimensional hydrodynamic simulations were performed using SPH, and the results of these are compared with calculations based on the linear theory of warped discs. We consider primarily the physical regime in which the dimensionless viscosity parameter `alpha' disc aspect ratio, so that bending waves are expected to propagate. We also present calculations in which `alpha' > H/r, where the warps are expected to behave diffusively. Small amplitude perturbations are studied in both Keplerian and slightly non Keplerian discs, and we find that the SPH results can be reasonably well fitted by those of the linear theory. The main results of these calculations are: (1) the warp in Keplerian discs when `alpha' H/r, (3) the non Keplerian discs exhibit a substantially more dispersive behaviour of the warps. Initially imposed higher amplitude nonlinear warping disturbances were studied in Keplerian discs. The results indicate that nonlinear warps can lead to the formation of shocks, and that the evolution of the warp becomes less wave-like and more diffusive in character. This work is relevant to the study of the warped accretion discs that may occur around Kerr black holes or in misaligned binary systems. The results indicate that SPH can accurately model the hydrodynamics of warped discs, even when using rather modest numbers of particles.
OLD DOMINION UNIVERSITY University Policies and Procedures
AND ADMINISTRATOR RECRUITMENT FUNDING PROCEDURE Statement: University Recruitment Budget (1) The university6010 - 1 OLD DOMINION UNIVERSITY University Policies and Procedures 6010 - FACULTY maintains a central budget, called the University Recruitment Budget, for the support of essential
1 Columbia University--The University Seminars COLUMBIA UNIVERSITY
Champagne, Frances A.
1 Columbia University--The University Seminars COLUMBIA UNIVERSITY T H E U N I V E R S I T Y S E M. Belknap Professor Emeritus of Russian, Columbia University, Director Emeritus of The University Seminars, Columbia University Susan Boynton Associate Professor of Music, Columbia University Ester Fuchs Professor
Yang, Zhaoqing; Khangaonkar, Tarang; Wang, Taiping
2010-08-01T23:59:59.000Z
In this report we describe the 1) the expansion of the PNNL hydrodynamic model domain to include the continental shelf along the coasts of Washington, Oregon, and Vancouver Island; and 2) the approach and progress in developing the online/Internet disseminations of model results and outreach efforts in support of the Puget Sound Operational Forecast System (PS-OPF). Submittal of this report completes the work on Task 2.1.2, Effects of Physical Systems, Subtask 2.1.2.1, Hydrodynamics, for fiscal year 2010 of the Environmental Effects of Marine and Hydrokinetic Energy project.
Robinson, A. P. L.; Schmitz, H. [Central Laser Facility, STFC Rutherford-Appleton Laboratory, Didcot OX11 0QX (United Kingdom)] [Central Laser Facility, STFC Rutherford-Appleton Laboratory, Didcot OX11 0QX (United Kingdom); Pasley, J. [Central Laser Facility, STFC Rutherford-Appleton Laboratory, Didcot OX11 0QX (United Kingdom) [Central Laser Facility, STFC Rutherford-Appleton Laboratory, Didcot OX11 0QX (United Kingdom); York Plasma Institute, University of York, York YO10 5DD (United Kingdom)
2013-12-15T23:59:59.000Z
Resistively guiding laser-generated fast electron beams in targets consisting of a resistive wire embedded in lower Z material should allow one to rapidly heat the wire to over 100 eV over a substantial distance without strongly heating the surrounding material. On the multi-ps timescale, this can drive hydrodynamic motion in the surrounding material. Thus, ultra-intense laser solid interactions have the potential as a controlled driver of radiation hydrodynamics in solid density material. In this paper, we assess the laser and target parameters needed to achieve such rapid and controlled heating of the embedded wire.
sequence of spectral energy distributions computed from our oxygen star model with a dust shell composed.: Hydrodynamical Models of Circumstellar Dust Shells Figure 2. Top: Time sequence of spectral energy distributionsM. Steffen et al.: Hydrodynamical Models of Circumstellar Dust Shells 5 Figure 3. Top: Time
DIMACS Center Rutgers University
Hopkins University Andrew Patrick, NRC Canada Norman Sadeh, Carnegie Mellon University Working Group University Mark Ackerman, University of Michigan Fabian Monrose, Johns Hopkins University Andrew Patrick, NRC Canada Norman Sadeh, Carnegie Mellon University Workshop: Cryptography: Theory Meets Practice Dates
ADMINISTRATIVE UNIVERSITY POLICY
ADMINISTRATIVE UNIVERSITY POLICY FACULTY UNIVERSITY POLICY STUDENT UNIVERSITY POLICY Issue stakeholder list "Log-In" of Proposed University Policy with the University Compliance Committee (UCC) UCC identifies which track (i.e., Administrative, Faculty, or Student) the proposed University Policy
Collective flow in event-by-event transport plus hydrodynamics hybrid approach
Rajeev S. Bhalerao; Amaresh Jaiswal; Subrata Pal
2015-03-03T23:59:59.000Z
Complete evolution of the strongly interacting matter formed in ultra-relativistic heavy-ion collisions is studied within a coupled Boltzmann and relativistic viscous hydrodynamics approach. For the initial non-equilibrium evolution phase, we employ the AMPT model that explicitly includes event-by-event fluctuations in the number and positions of the participating nucleons as well as of the produced partons with subsequent parton transport. The ensuing near-equilibrium evolution of quark-gluon and hadronic matter is modeled within the 2+1D relativistic viscous hydrodynamics. We probe the role of parton dynamics in generating and maintaining the spatial anisotropy in the pre-equilibrium phase. Substantial eccentricities epsilon_n are found to be generated in the event-by-event fluctuations in parton production from initial nucleon-nucleon collisions. For ultra-central heavy-ion collisions, the model is able to explain qualitatively the unexpected hierarchy of the harmonic flow coefficients v_n(pT) (n=2-6) observed at the LHC energy. We find that the results for v_n(pT) are rather insensitive to the variation (within a range) of the time of switchover from AMPT parton transport to hydrodynamic evolution. The usual Grad and the recently proposed Chapman-Enskog-like (non-equilibrium) single-particle distribution functions are found to give very similar results for v_n (n=2-4). The model describes well both the RHIC and LHC data for v_n(pT) at various centralities, with a constant shear viscosity to entropy density ratio 0.08 and 0.12, respectively. The event-by-event distributions of v_{2,3} are in good agreement with the LHC data for mid-central collisions. The linear response relation v_n = k_n*epsilon_n is found to be true for n=2,3, except at large values of epsilon_n, where a larger value of k_n is required, suggesting a small admixture of positive nonlinear response even for n=2,3.
Modifications of Carbonate Fracture Hydrodynamic Properties by CO{sub 2}-Acidified Brine Flow
Deng, Hang; Ellis, Brian R.; Peters, Catherine A.; Fitts, Jeffrey P.; Crandall, Dustin; Bromhal, Grant S.
2013-08-01T23:59:59.000Z
Acidic reactive flow in fractures is relevant in subsurface activities such as CO{sub 2} geological storage and hydraulic fracturing. Understanding reaction-induced changes in fracture hydrodynamic properties is essential for predicting subsurface flows such as leakage, injectability, and fluid production. In this study, x-ray computed tomography scans of a fractured carbonate caprock were used to create three dimensional reconstructions of the fracture before and after reaction with CO{sub 2}-acidified brine (Ellis et al., 2011, Greenhouse Gases: Sci. Technol., 1:248-260). As expected, mechanical apertures were found to increase substantially, doubling and even tripling in some places. However, the surface geometry evolved in complex ways including ‘comb-tooth’ structures created from preferential dissolution of calcite in transverse sedimentary bands, and the creation of degraded zones, i.e. porous calcite-depleted areas on reacted fracture surfaces. These geometric alterations resulted in increased fracture roughness, as measured by surface Z{sub 2} parameters and fractal dimensions D{sub f}. Computational fluid dynamics (CFD) simulations were conducted to quantify the changes in hydraulic aperture, fracture transmissivity and permeability. The results show that the effective hydraulic apertures are smaller than the mechanical apertures, and the changes in hydraulic apertures are nonlinear. Overestimation of flow rate by a factor of two or more would be introduced if fracture hydrodynamic properties were based on mechanical apertures, or if hydraulic aperture is assumed to change proportionally with mechanical aperture. The differences can be attributed, in part, to the increase in roughness after reaction, and is likely affected by contiguous transverse sedimentary features. Hydraulic apertures estimated by the 1D statistical model and 2D local cubic law (LCL) model are consistently larger than those calculated from the CFD simulations. In addition, a novel ternary segmentation method was devised to handle the degraded zones, allowing for a bounding analysis of the effects on hydraulic properties. We found that the degraded zones account for less than 15% of the fracture volume, but cover 70% to 80% of the fracture surface. When the degraded zones are treated as part of the fracture, the fracture transmissivities are two to four times larger because the fracture surfaces after reaction are not as rough as they would be if one considers the degraded zone as part of the rock. Therefore, while degraded zones created during geochemical reactions may not significantly increase mechanical aperture, this type of feature cannot be ignored and should be treated with prudence when predicting fracture hydrodynamic properties.
CONSORTIUM MEMBERS EU Universities
Heermann, Dieter W.
coordinator > University of Tirana, Albania > University of Sarajevo, Bosnia & Herzegovina > South East Foundation, Belgium > University of Tuzla, Bosnia & Herzegovina > Roma Virtual Network, Israel > University
Gladwell, John Stuart
1961-01-01T23:59:59.000Z
and the effects of gravity forces are ignored. Some other bases of sxmx1itude are: (1) Weber Number; used when surf'ace tension effects predoxninate, (2) Mach Number; used when forces involve elastic com- pression; e. g. , water-hammer effect, (3) Cavitation.... Vertical distance between any two points on the spillway, ft. INTRODUCTION The ski-jump spillway is an arrangexnent by which a flow of water is carried down a chute to a slightly upturned lip (forming a bucket) that throws the jet out over a pool below...
Fish, Frank
1991-01-01T23:59:59.000Z
THE JOURNAL OF EXPERIMENTAL ZOOLOGY 258164-173 (1991) Hydrodynamics of the Feet of Fish-Catching Bats: Influence of the Water Surface on Drag and Morphological Design FRANK E. FISH, BRAD R. BLOOD and Pizonyx uiuesi, display similar hind foot mor- phologies specialized for their fish-catching habits
Boris V. Alexeev; Irina V. Ovchinnikova
2012-11-24T23:59:59.000Z
The motion of the charged particles in graphen in the frame of the quantum non-local hydrodynamic description is considered. It is shown as results of the mathematical modeling that the mentioned motion is realizing in the soliton forms. The dependence of the size and structure of solitons on the different physical parameters is investigated.
Salvaggio, Carl
, USA b Savannah River National Laboratory, Aiken, South Carolina, USA c Rochester Institute. INTRODUCTION The ALGE code is a hydrodynamic model developed by Savannah River National Laboratory (SRNL of Technology, Center for Imaging Science, Digital Imaging and Remote Sensing Laboratory, Rochester, New York
A new algorithm for modelling photoionising radiation in smoothed particle hydrodynamics
James Dale; Barbara Ercolano; Cathie Clarke
2007-05-23T23:59:59.000Z
We present a new fast algorithm which allows the simulation of ionising radiation emitted from point sources to be included in high-resolution three-dimensional smoothed particle hydrodynamics simulations of star cluster formation. We employ a Str\\"omgren volume technique in which we use the densities of particles near the line-of-sight between the source and a given target particle to locate the ionisation front in the direction of the target. Along with one--dimensional tests, we present fully three--dimensional comparisons of our code with the three--dimensional Monte-Carlo radiative transfer code, MOCASSIN, and show that we achieve good agreement, even in the case of highly complex density fields.
Two-dimensional segmentation of small convective patterns in radiation hydrodynamics simulations
Lemmerer, B; Hanslmeier, A; Veronig, A; Thonhofer, S; Grimm-Strele, H; Kariyappa, R
2015-01-01T23:59:59.000Z
Recent results from high-resolution solar granulation observations indicate the existence of a population of small granular cells that are smaller than 600 km in diameter. These small convective cells strongly contribute to the total area of granules and are located in the intergranular lanes, where they form clusters and chains. We study high-resolution radiation hydrodynamics simulations of the upper convection zone and photosphere to detect small granular cells, define their spatial alignment, and analyze their physical properties. We developed an automated image-segmentation algorithm specifically adapted to high-resolution simulations to identify granules. The resulting segmentation masks were applied to physical quantities, such as intensity and vertical velocity profiles, provided by the simulation. A new clustering algorithm was developed to study the alignment of small granular cells. This study shows that small granules make a distinct contribution to the total area of granules and form clusters of ...
Prediction of hydrodynamic forces on oscillating bodies by unsteady turbulent wake theory
Matsumoto, Koichiro [NKK Corp., Tsu (Japan)
1994-12-31T23:59:59.000Z
In the paper presented at ISOPE-91, Edinburgh the author introduced a new practical theory to predict hydrodynamic forces acting on arbitrarily oscillating bodies. The theory is based on the assumption that the Morison`s equation can be applied with constant drag and mass coefficients provided that wake velocities produced by the body motions in all past history are properly corrected for. The induced wake velocity is calculated by the unsteady turbulent wake theory. In the present paper this new theory is applied to practical body oscillation problems such as the irregular oscillation of a cylinder, an oscillating cylinder in steady current, and the elliptic or circular oscillation of a cylinder. Some of the theoretical calculation results are compared with experiments, and the applicability of the theory is discussed.
From AdS/CFT correspondence to hydrodynamics. II. Sound waves
G. Policastro; D. T. Son; A. O. Starinets
2005-07-26T23:59:59.000Z
As a non-trivial check of the non-supersymmetric gauge/gravity duality, we use a near-extremal black brane background to compute the retarded Green's functions of the stress-energy tensor in N=4 super-Yang-Mills (SYM) theory at finite temperature. For the long-distance, low-frequency modes of the diagonal components of the stress-energy tensor, hydrodynamics predicts the existence of a pole in the correlators corresponding to propagation of sound waves in the N=4 SYM plasma. The retarded Green's functions obtained from gravity do indeed exhibit this pole, with the correct values for the sound speed and the rate of attenuation.
Shunsuke Yabunaka; Ryuichi Okamoto; Akira Onuki
2015-05-23T23:59:59.000Z
We investigate bridging and aggregation of two colloidal particles in a near-critical binary mixture when the fluid far from the particles is outside the coexistence (CX) curve and is rich in the component disfavored by the colloid surfaces. In such situations, the adsorption-induced interaction is enhanced, leading to bridging and aggregation of the particles. We realize bridging firstly by changing the temperature with a fixed interparticle separation and secondly by letting the two particles aggregate. The interparticle attractive force dramatically increases upon bridging. The dynamics is governed by hydrodynamic flow around the colloid surfaces. In aggregation, the adsorption layers move with the particles and squeezing occurs at narrow separation. We take into account the renormalization effect due to the critical fluctuations using the recent local functional theory [J. Chem. Phys. 136, 114704 (2012)].
Analytical and numerical Gubser solutions of the second-order hydrodynamics
Long-Gang Pang; Yoshitaka Hatta; Xin-Nian Wang; Bo-Wen Xiao
2014-12-10T23:59:59.000Z
Evolution of quark-gluon plasma (QGP) near equilibrium can be described by the second-order relativistic viscous hydrodynamic equations. Consistent and analytically verifiable numerical solutions are critical for phenomenological studies of the collective behavior of QGP in high-energy heavy-ion collisions. A novel analytical solution based on the conformal Gubser flow which is a boost-invariant solution with transverse fluid velocity is presented. It is used to verify with high precision the numerical solution with a newly developed $(3+1)$-dimensional second-order viscous hydro code (CLVisc). The perfect agreement between the analytical and numerical solutions demonstrates the reliability of the numerical simulations with the second-order viscous corrections. This lays the foundation for future phenomenological studies that allow one to gain access to the second-order transport coefficients.
Hassanein, A.; Konkashbaev, I.
1999-10-25T23:59:59.000Z
Loss of plasma confinement causes surface and structural damage to plasma-facing materials (PFMs) and remains a major obstacle for tokamak reactors. The deposited plasma energy results in surface erosion and structural failure. The surface erosion consists of vaporization, spallation, and liquid splatter of metallic materials, while the structural damage includes large temperature increases in structural materials and at the interfaces between surface coatings and structural members. Comprehensive models (contained in the HEIGHTS computer simulation package) are being used self-consistently to evaluate material damage. Splashing mechanisms occur as a result of volume bubble boiling and liquid hydrodynamic instabilities and brittle destruction mechanisms of nonmelting materials. The effect of macroscopic erosion on total mass losses and lifetime is evaluated. The macroscopic erosion products may further protect PFMs from severe erosion (via the droplet-shielding effect) in a manner similar to that of the vapor shielding concept.
Wang, Taiping; Yang, Zhaoqing; Khangaonkar, Tarang
2010-04-22T23:59:59.000Z
In this study, a hydrodynamic model based on the unstructured-grid finite volume coastal ocean model (FVCOM) was developed for Bellingham Bay, Washington. The model simulates water surface elevation, velocity, temperature, and salinity in a three-dimensional domain that covers the entire Bellingham Bay and adjacent water bodies, including Lummi Bay, Samish Bay, Padilla Bay, and Rosario Strait. The model was developed using Pacific Northwest National Laboratory’s high-resolution Puget Sound and Northwest Straits circulation and transport model. A sub-model grid for Bellingham Bay and adjacent coastal waters was extracted from the Puget Sound model and refined in Bellingham Bay using bathymetric light detection and ranging (LIDAR) and river channel cross-section data. The model uses tides, river inflows, and meteorological inputs to predict water surface elevations, currents, salinity, and temperature. A tidal open boundary condition was specified using standard National Oceanic and Atmospheric Administration (NOAA) predictions. Temperature and salinity open boundary conditions were specified based on observed data. Meteorological forcing (wind, solar radiation, and net surface heat flux) was obtained from NOAA real observations and National Center for Environmental Prediction North American Regional Analysis outputs. The model was run in parallel with 48 cores using a time step of 2.5 seconds. It took 18 hours of cpu time to complete 26 days of simulation. The model was calibrated with oceanographic field data for the period of 6/1/2009 to 6/26/2009. These data were collected specifically for the purpose of model development and calibration. They include time series of water-surface elevation, currents, temperature, and salinity as well as temperature and salinity profiles during instrument deployment and retrieval. Comparisons between model predictions and field observations show an overall reasonable agreement in both temporal and spatial scales. Comparisons of root mean square error values for surface elevation, velocity, temperature, and salinity time series are 0.11 m, 0.10 m/s, 1.28oC, and 1.91 ppt, respectively. The model was able to reproduce the salinity and temperature stratifications inside Bellingham Bay. Wetting and drying processes in tidal flats in Bellingham Bay, Samish Bay, and Padilla Bay were also successfully simulated. Both model results and observed data indicated that water surface elevations inside Bellingham Bay are highly correlated to tides. Circulation inside the bay is weak and complex and is affected by various forcing mechanisms, including tides, winds, freshwater inflows, and other local forcing factors. The Bellingham Bay model solution was successfully linked to the NOAA oil spill trajectory simulation model “General NOAA Operational Modeling Environment (GNOME).” Overall, the Bellingham Bay model has been calibrated reasonably well and can be used to provide detailed hydrodynamic information in the bay and adjacent water bodies. While there is room for further improvement with more available data, the calibrated hydrodynamic model provides useful hydrodynamic information in Bellingham Bay and can be used to support sediment transport and water quality modeling as well as assist in the design of nearshore restoration scenarios.
Investigating puzzling aspects of the quantum theory by means of its hydrodynamic formulation
Sanz, A S
2015-01-01T23:59:59.000Z
Bohmian mechanics, a hydrodynamic formulation of the quantum theory, constitutes a useful resource to analyze the role of the phase as the mechanism responsible for the dynamical evolution of quantum systems. Here this role is discussed in the context of quantum interference. Specifically, it is shown that when dealing with two wave-packet coherent superpositions this phenomenon is analogous to an effective collision of a single wave packet with a barrier. This effect is illustrated by means of a numerical simulation of Young's two-slit experiment. Furthermore, outcomes from this analysis are also applied to a realistic simulation of Wheeler's delayed choice experiment. As it is shown, in both cases the Bohmian formulation helps to understand in a natural way (and, therefore, to demystify) what are typically regarded as paradoxical aspects of the quantum theory, simply stressing the important dynamical role played by the quantum phase. Accordingly, our conception of quantum systems should not rely on artifici...
J. KAO; D. COOPER; ET AL
2000-11-01T23:59:59.000Z
As lidar technology is able to provide fast data collection at a resolution of meters in an atmospheric volume, it is imperative to promote a modeling counterpart of the lidar capability. This paper describes an integrated capability based on data from a scanning water vapor lidar and a high-resolution hydrodynamic model (HIGRAD) equipped with a visualization routine (VIEWER) that simulates the lidar scanning. The purpose is to better understand the spatial and temporal representativeness of the lidar measurements and, in turn, to extend their utility in studying turbulence fields in the atmospheric boundary layer. Raman lidar water vapor data collected over the Pacific warm pool and the simulations with the HIGRAD code are used for identifying the underlying physics and potential aliasing effects of spatially resolved lidar measurements. This capability also helps improve the trade-off between spatial-temporal resolution and coverage of the lidar measurements.
Scaling theory for hydrodynamic lubrication, with application to non-Newtonian lubricants
Patrick B. Warren
2015-02-04T23:59:59.000Z
Scaling arguments are developed for the load balance in hydrodynamic lubrication, and applied to non-Newtonian lubricants with a shear-thinning rheology typical of a structured liquid. It is argued that the shear thinning regime may be mechanically unstable in lubrication flow, and consequently the Stribeck (friction) curve should be discontinuous, with possible hysteresis. Further analysis suggests that normal stress and flow transience (stress overshoot) do not destroy this basic picture, although they may provide stabilising mechanisms at higher shear rates. Extensional viscosity is also expected to be insignificant unless the Trouton ratio is large. A possible application to recent theories of shear thickening in non-Brownian particulate suspensions is indicated.
Hydrodynamical adaptive mesh refinement simulations of turbulent flows - I. Substructure in a wind
Iapichino, L; Schmidt, W; Niemeyer, J C
2008-01-01T23:59:59.000Z
The problem of the resolution of turbulent flows in adaptive mesh refinement (AMR) simulations is investigated by means of 3D hydrodynamical simulations in an idealised setup, representing a moving subcluster during a merger event. AMR simulations performed with the usual refinement criteria based on local gradients of selected variables do not properly resolve the production of turbulence downstream of the cluster. Therefore we apply novel AMR criteria which are optimised to follow the evolution of a turbulent flow. We demonstrate that these criteria provide a better resolution of the flow past the subcluster, allowing us to follow the onset of the shear instability, the evolution of the turbulent wake and the subsequent back-reaction on the subcluster core morphology. We discuss some implications for the modelling of cluster cold fronts.
Hydrodynamical adaptive mesh refinement simulations of turbulent flows - I. Substructure in a wind
L. Iapichino; J. Adamek; W. Schmidt; J. C. Niemeyer
2008-07-01T23:59:59.000Z
The problem of the resolution of turbulent flows in adaptive mesh refinement (AMR) simulations is investigated by means of 3D hydrodynamical simulations in an idealised setup, representing a moving subcluster during a merger event. AMR simulations performed with the usual refinement criteria based on local gradients of selected variables do not properly resolve the production of turbulence downstream of the cluster. Therefore we apply novel AMR criteria which are optimised to follow the evolution of a turbulent flow. We demonstrate that these criteria provide a better resolution of the flow past the subcluster, allowing us to follow the onset of the shear instability, the evolution of the turbulent wake and the subsequent back-reaction on the subcluster core morphology. We discuss some implications for the modelling of cluster cold fronts.
Redesign of turbine-pump impeller and diffuser using hydrodynamic design techniques. Final report
Hamrick, J.T.
1980-04-01T23:59:59.000Z
It is indicated that in 1976 the average operating efficiency of well irrigation pumps in the US, including losses in the column pipe and line shaft, was 55.5%, but information is presented to show that losses in a pumping system can be reduced and that it is possible to reach a goal of 82% system efficiency. Hydrodynamic design methods which are used to analyze and modify a commercially available pump are presented. The results of tests with the pump are presented for which delivery losses were reduced by means of a packer at the pump and for which line shaft losses were reduced by means of a high strength line shaft. Methods of designing pumps that have a broader high efficiency range are explored, and a design approach for doing so is presented. The method was not evaluated experimentally. (MCW)
Radiative hydrodynamics in the highly super adiabatic layer of stellar evolution models
F. J. Robinson; P. Demarque; S. Sofia; K. L. Chan; Y. -C. Kim; D. B. Guenther
2000-11-02T23:59:59.000Z
We present results of three dimensional simulations of the uppermost part of the sun, at 3 stages of its evolution. Each model includes physically realistic radiative-hydrodynamics (the Eddington approximation is used in the optically thin region), varying opacities and a realistic equation of state (full treatment of the ionization of H and He). In each evolution model, we investigate a domain, which starts at the top of the photosphere and ends just inside the convection zone (about 2400 km in the sun model). This includes all of the super-adiabatic layer (SAL). Due to the different positions of the three models in the $log (g) $ vs $log T_{eff}$ plane, the more evolved models have lower density atmospheres. The reduction in density causes the amount of overshoot into the radiation layer, to be greater in the more evolved models.
Predictions for {radical} (s) =200A; GeV Au+Au collisions from relativistic hydrodynamics
Schlei, B.R. [Physics Division, P-25, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)] [Physics Division, P-25, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Schlei, B.R.; Strottman, D. [Theoretical Division, DDT-DO, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)] [Theoretical Division, DDT-DO, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
1999-01-01T23:59:59.000Z
The relativistic hydrodynamical model HYLANDER-C is used to give estimates for single inclusive particle momentum spectra in {radical} (s) =200 GeV/nucleon Au+Au collisions that will be investigated experimentally in the near future. The predictions are based on initial conditions that the initial fireball has a longitudinal extension of 1.6 fm and an initial energy density of 30.8 GeV/fm{sup 3} as obtained from a cascade model. For the collision energy considered here, different stopping scenarios are explored for the first time. Our calculations give particle yields of the order of 10thinsp000 to 20thinsp000 charged particles per event. {copyright} {ital 1999} {ital The American Physical Society}
Single-particle spectral density of a Bose gas in the two-fluid hydrodynamic regime
Arahata, Emiko; Nikuni, Tetsuro; Griffin, Allan [Department of Physics, Faculty of Science, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601 (Japan); Department of Physics, University of Toronto, Toronto, Ontario, M5S 1A7 (Canada)
2011-11-15T23:59:59.000Z
In Bose superfluids, the single-particle Green's function can be directly related to the superfluid velocity-velocity correlation function in the hydrodynamic regime. An explicit expression for the single-particle spectral density was originally written down by Hohenberg and Martin in 1965, starting from the two-fluid equations for a superfluid. We give a simple derivation of their results. Using these results, we calculate the relative weights of first and second sound modes in the single-particle spectral density as a function of temperature in a uniform Bose gas. We show that the second sound mode makes a dominant contribution to the single-particle spectrum in a relatively high-temperature region. We also discuss the possibility of experimental observation of the second sound mode in a Bose gas by photoemission spectroscopy.
An efficient approach to unstructured mesh hydrodynamics on the cell broadband engine (u)
Ferenbaugh, Charles R [Los Alamos National Laboratory
2010-12-14T23:59:59.000Z
Unstructured mesh physics for the Cell Broadband Engine (CBE) has received little or no attention to date, largely because the CBE architecture poses particular challenges for unstructured mesh algorithms. SPU memory management strategies such as data preloading cannot be applied to the irregular memory storage patterns of unstructured meshes; and the SPU vector instruction set does not support the indirect addressing needed by connectivity arrays. This paper presents an approach to unstructured mesh physics that addresses these challenges, by creating a new mesh data structure and reorganizing code to give efficient CBE performance. The approach is demonstrated on the FLAG production hydrodynamics code using standard test problems, and results show an average speedup of more than 5x over the original code.
Investigating the Magnetorotational Instability with Dedalus, and Open-Souce Hydrodynamics Code
Burns, Keaton J; /UC, Berkeley, aff SLAC
2012-08-31T23:59:59.000Z
The magnetorotational instability is a fluid instability that causes the onset of turbulence in discs with poloidal magnetic fields. It is believed to be an important mechanism in the physics of accretion discs, namely in its ability to transport angular momentum outward. A similar instability arising in systems with a helical magnetic field may be easier to produce in laboratory experiments using liquid sodium, but the applicability of this phenomenon to astrophysical discs is unclear. To explore and compare the properties of these standard and helical magnetorotational instabilities (MRI and HRMI, respectively), magnetohydrodynamic (MHD) capabilities were added to Dedalus, an open-source hydrodynamics simulator. Dedalus is a Python-based pseudospectral code that uses external libraries and parallelization with the goal of achieving speeds competitive with codes implemented in lower-level languages. This paper will outline the MHD equations as implemented in Dedalus, the steps taken to improve the performance of the code, and the status of MRI investigations using Dedalus.
Causal dissipative hydrodynamics for QGP fluid in 2+1 dimensions
A. K. Chaudhuri
2007-08-01T23:59:59.000Z
In 2nd order causal dissipative theory, space-time evolution of QGP fluid is studied in 2+1 dimensions. Relaxation equations for shear stress tensors are solved simultaneously with the energy-momentum conservation equations. Comparison of evolution of ideal and viscous QGP fluid, initialized under the same conditions, e.g. same equilibration time, energy density and velocity profile, indicate that in a viscous dynamics, energy density or temperature of the fluid evolve slowly, than in an ideal fluid. Cooling gets slower as viscosity increases. Transverse expansion also increases in a viscous dynamics. For the first time we have also studied elliptic flow of 'quarks' in causal viscous dynamics. It is shown that elliptic flow of quarks saturates due to non-equilibrium correction to equilibrium distribution function, and can not be mimicked by an ideal hydrodynamics.
Viscous hydrodynamics description of $?$ meson production in Au+Au and Cu+Cu collisions
A. K. Chaudhuri
2009-01-27T23:59:59.000Z
In the Israel-Stewart's theory of 2nd order dissipative hydrodynamics, we have simulated $\\phi$ production in Au+Au and Cu+Cu collisions at $\\sqrt{s}_{NN}$=200 GeV. Evolution of QGP fluid with viscosity over the entropy ratio $\\eta/s$=0.25, thermalised at $\\tau_i$=0.2 fm, with initial energy density $\\epsilon_i$=5.1 $GeV/fm^3$ explains the experimental data on $\\phi$ multiplicity, integrated $v_2$, mean $p_T$, $p_T$ spectra and elliptic flow in central and mid-central Au+Au collisions. $\\eta/s$=0.25 is also consistent with centrality dependence of $\\phi$ $p_T$ spectra in Cu+Cu collisions. The central energy density in Cu+Cu collisions is $\\epsilon_i$=3.48 $GeV/fm^3$.
Hydrodynamic Scaling Analysis of Nuclear Fusion driven by ultra-intense laser-plasma interactions
Sachie Kimura; Aldo Bonasera
2012-07-24T23:59:59.000Z
We discuss scaling laws of fusion yields generated by laser-plasma interactions. The yields are found to scale as a function of the laser power. The origin of the scaling law in the laser driven fusion yield is derived in terms of hydrodynamic scaling. We point out that the scaling properties can be attributed to the laser power dependence of three terms: the reaction rate, the density of the plasma and the projected range of the plasma particle in the target medium. The resulting scaling relations have a predictive power that enables estimating the fusion yield for a nuclear reaction which has not been investigated by means of the laser accelerated ion beams.
University of Michigan, Ann Arbor Indiana University, Bloomington
Wu, Yih-Min
/ 1 #12; 2005 4 University of Michigan, Ann Arbor Indiana University, Bloomington University of Illinois, Urbana-Champagne University of Michigan, Ann Arbor 19 Center University of Michigan, Georgetown University, University of Nebraska, University of Kansas University
Jian-Zhou Zhu
2014-07-31T23:59:59.000Z
Hydrodynamic helicity signatures the parity symmetry breaking, chirality, of the flow. Statistical hydrodynamics thus respect chirality, as symmetry breaking and restoration are key to their fundamentals, such as the spectral transfer direction and its mechanism. Homochiral sub-system of three-dimensional (3D) Navier-Stokes isotropic turbulence has been numerically realized with helical representation technique to present inverse energy cascade [Biferale et al., Phys. Rev. Lett., {\\bf 108}, 164501 (2012)]. The situation is analogous to 2D turbulence where inverse energy cascade, or more generally energy-enstrophy dual cascade scenario, was argued with the help of a negative temperature state of the absolute equilibrium by Kraichnan. Indeed, if the helicity in such a system is taken to be positive without loss of generality, a corresponding negative temperature state can be identified [Zhu et al., J. Fluid Mech., {\\bf 739}, 479 (2014)]. Here, for some specific chiral ensembles of turbulence, we show with the corresponding absolute equilibria that even if the helicity distribution over wavenumbers is sign definite, different \\textit{ansatzes} of the shape function, defined by the ratio between the specific helicity and energy spectra $s(k)=H(k)/E(k)$, imply distinct transfer directions, and we could have inverse-helicity and forward-energy dual transfers (with, say, $s(k)\\propto k^{-2}$ resulting in absolute equilibrium modal spectral density of energy $U(k)=\\frac{1}{\\alpha +\\beta k^{-2}}$, exactly the enstrophy one of two-dimensional Euler by Kraichan), simultaneous forward transfers (with $s(k)=constant$), or even no simply-directed transfer (with, say, non-monotonic $s(k) \\propto \\sin^2k$), besides the inverse-energy and forward-helicity dual transfers (with, say, $s(k)=k$ as in the homochiral case).
Effect of the Coriolis Force on the Hydrodynamics of Colliding Wind Binaries
M. Nicole Lemaster; James M. Stone; Thomas A. Gardiner
2007-02-16T23:59:59.000Z
Using fully three-dimensional hydrodynamic simulations, we investigate the effect of the Coriolis force on the hydrodynamic and observable properties of colliding wind binary systems. To make the calculations tractable, we assume adiabatic, constant velocity winds. The neglect of radiative driving, gravitational deceleration, and cooling limit the application of our models to real systems. However, these assumptions allow us to isolate the effect of the Coriolis force, and by simplifying the calculations, allow us to use a higher resolution (up to 640^3) and to conduct a larger survey of parameter space. We study the dynamics of collidng winds with equal mass loss rates and velocities emanating from equal mass stars on circular orbits, with a range of values for the ratio of the wind to orbital velocity. We also study the dynamics of winds from stars on elliptical orbits and with unequal strength winds. Orbital motion of the stars sweeps the shocked wind gas into an Archimedean spiral, with asymmetric shock strengths and therefore unequal postshock temperatures and densities in the leading and trailing edges of the spiral. We observe the Kelvin-Helmholtz instability at the contact surface between the shocked winds in systems with orbital motion even when the winds are identical. The change in shock strengths caused by orbital motion increases the volume of X-ray emitting post-shock gas with T > 0.59 keV by 63% for a typical system as the ratio of wind velocity to orbital velocity decreases to V_w/V_o = 2.5. This causes increased free-free emission from systems with shorter orbital periods and an altered time-dependence of the wind attenuation. We comment on the importance of the effects of orbital motion on the observable properties of colliding wind binaries.
Lucio Mayer; Stelios Kazantzidis; Andres Escala
2008-07-22T23:59:59.000Z
(Abridged) We review the results of the first multi-scale, hydrodynamical simulations of mergers between galaxies with central supermassive black holes (SMBHs) to investigate the formation of SMBH binaries in galactic nuclei. We demonstrate that strong gas inflows produce nuclear disks at the centers of merger remnants whose properties depend sensitively on the details of gas thermodynamics. In numerical simulations with parsec-scale spatial resolution in the gas component and an effective equation of state appropriate for a starburst galaxy, we show that a SMBH binary forms very rapidly, less than a million years after the merger of the two galaxies. Binary formation is significantly suppressed in the presence of a strong heating source such as radiative feedback by the accreting SMBHs. We also present preliminary results of numerical simulations with ultra-high spatial resolution of 0.1 pc in the gas component. These simulations resolve the internal structure of the resulting nuclear disk down to parsec scales and demonstrate the formation of a central massive object (~ 10^8 Mo) by efficient angular momentum transport. This is the first time that a radial gas inflow is shown to extend to parsec scales as a result of the dynamics and hydrodynamics involved in a galaxy merger, and has important implications for the fueling of SMBHs. Due to the rapid formation of the central clump, the density of the nuclear disk decreases significantly in its outer region, reducing dramatically the effect of dynamical friction and leading to the stalling of the two SMBHs at a separation of ~1 pc. We discuss how the orbital decay of the black holes might continue in a more realistic model which incorporates star formation and the multi-phase nature of the ISM.
Universal properties of cold holographic matter
Niko Jokela; Alfonso V. Ramallo
2015-03-14T23:59:59.000Z
We study the collective excitations of holographic quantum liquids formed in the low energy theory living at the intersection of two sets of D-branes. The corresponding field theory dual is a supersymmetric Yang-Mills theory with massless matter hypermultiplets in the fundamental representation of the gauge group which generically live on a defect of the unflavored theory. Working in the quenched (probe) approximation, we focus on determining the universal properties of these systems. We analyze their thermodynamics, the speed of first sound, the diffusion constant, and the speed of zero sound. We study the influence of temperature, chemical potential, and magnetic field on these quantities, as well as on the corresponding collisionless/hydrodynamic crossover. We also generalize the alternative quantization for all conformally $AdS_4$ backgrounds and study the anyonic correlators.
Universal properties of cold holographic matter
Jokela, Niko
2015-01-01T23:59:59.000Z
We study the collective excitations of holographic quantum liquids formed in the low energy theory living at the intersection of two sets of D-branes. The corresponding field theory dual is a supersymmetric Yang-Mills theory with massless matter hypermultiplets in the fundamental representation of the gauge group which generically live on a defect of the unflavored theory. Working in the quenched (probe) approximation, we focus on determining the universal properties of these systems. We analyze their thermodynamics, the speed of first sound, the diffusion constant, and the speed of zero sound. We study the influence of temperature, chemical potential, and magnetic field on these quantities, as well as on the corresponding collisionless/hydrodynamic crossover. We also generalize the alternative quantization for all conformally $AdS_4$ backgrounds and study the anyonic correlators.
Hydrogen Reionization in the Illustris Universe
Bauer, Andreas; Vogelsberger, Mark; Genel, Shy; Torrey, Paul; Sijacki, Debora; Nelson, Dylan; Hernquist, Lars
2015-01-01T23:59:59.000Z
Hydrodynamical simulations of galaxy formation such as the Illustris simulations have progressed to a state where they approximately reproduce the observed stellar mass function from high to low redshift. This in principle allows self-consistent models of reionization that exploit the accurate representation of the diffuse gas distribution together with the realistic growth of galaxies provided by these simulations, within a representative cosmological volume. In this work, we apply and compare two radiative transfer algorithms implemented in a GPU-accelerated code to the $106.5\\,{\\rm Mpc}$ wide volume of Illustris in postprocessing in order to investigate the reionization transition predicted by this model. We find that the first generation of galaxies formed by Illustris is just about able to reionize the universe by redshift $z\\sim 7$, provided quite optimistic assumptions about the escape fraction and the resolution limitations are made. Our most optimistic model finds an optical depth of $\\tau\\simeq 0.06...
Zink+, Doug Montgomery, Jin Ho Hahm# National Institute of Standards and Technology (NIST) *University Label table Label table APIs Label routing APIs RSVP label APIs user level kernel level NIST Switch 6
THE BIGGEST EXPLOSIONS IN THE UNIVERSE
Johnson, Jarrett L.; Whalen, Daniel J.; Smidt, Joseph [Nuclear and Particle Physics, Astrophysics and Cosmology Group (T-2), Thermonuclear Applications Physics Group (XTD-6), Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Even, Wesley; Fryer, Chris L. [Computational Physics and Methods Group (CCS-2), Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Heger, Alex [Monash Centre for Astrophysics, Monash University, VIC 3800 (Australia); Chen, Ke-Jung, E-mail: jlj@lanl.gov [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States)
2013-10-01T23:59:59.000Z
Supermassive primordial stars are expected to form in a small fraction of massive protogalaxies in the early universe, and are generally conceived of as the progenitors of the seeds of supermassive black holes (BHs). Supermassive stars with masses of ?55, 000 M{sub ?}, however, have been found to explode and completely disrupt in a supernova (SN) with an energy of up to ?10{sup 55} erg instead of collapsing to a BH. Such events, ?10, 000 times more energetic than typical SNe today, would be among the biggest explosions in the history of the universe. Here we present a simulation of such a SN in two stages. Using the RAGE radiation hydrodynamics code, we first evolve the explosion from an early stage through the breakout of the shock from the surface of the star until the blast wave has propagated out to several parsecs from the explosion site, which lies deep within an atomic cooling dark matter (DM) halo at z ? 15. Then, using the GADGET cosmological hydrodynamics code, we evolve the explosion out to several kiloparsecs from the explosion site, far into the low-density intergalactic medium. The host DM halo, with a total mass of 4 × 10{sup 7} M{sub ?}, much more massive than typical primordial star-forming halos, is completely evacuated of high-density gas after ?< 10 Myr, although dense metal-enriched gas recollapses into the halo, where it will likely form second-generation stars with metallicities of ? 0.05 Z{sub ?} after ?> 70 Myr. The chemical signature of supermassive star explosions may be found in such long-lived second-generation stars today.
University Archives University of Missouri at Columbia
Taylor, Jerry
University Archives University of Missouri at Columbia 703 Lewis Hall University of Missouri-Columbia Archives of the University of Missouri at Columbia reserves the right to refuse permission to individuals agree to credit the University Archives of the University of Missouri at Columbia in accordance
UNIVERSITY STANDARDS AND REGULATIONS
Royer, Dana
20142015 UNIVERSITY STANDARDS AND REGULATIONS #12;Wesleyan University does not discriminate STANDARDS OF CONDUCT
UNIVERSITY STANDARDS AND REGULATIONS
Royer, Dana
20132014 UNIVERSITY STANDARDS AND REGULATIONS #12;Wesleyan University does not discriminate STANDARDS OF CONDUCT
UNIVERSITY OF ABERDEEN UNIVERSITY COURT
Levi, Ran
from Talisman towards student scholarships and from a number of oil companies towards a centre to be a post-doctoral researcher. The University had been ranked as one of the top twenty institutions outside
EVOLUTION AND HYDRODYNAMICS OF THE VERY BROAD X-RAY LINE EMISSION IN SN 1987A
Dewey, D.; Canizares, C. R. [MIT Kavli Institute, Cambridge, MA 02139 (United States); Dwarkadas, V. V. [Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 (United States); Haberl, F.; Sturm, R., E-mail: dd@space.mit.edu, E-mail: vikram@oddjob.uchicago.edu [Max-Planck-Institut fuer extraterrestrische Physik, Giessenbachstrasse, Garching D-85748 (Germany)
2012-06-20T23:59:59.000Z
Observations of SN 1987A by the Chandra High Energy Transmission Grating (HETG) in 1999 and the XMM-Newton Reflection Grating Spectrometer (RGS) in 2003 show very broad (v-b) lines with a full width at half-maximum (FWHM) of order 10{sup 4} km s{sup -1}; at these times the blast wave (BW) was primarily interacting with the H II region around the progenitor. Since then, the X-ray emission has been increasingly dominated by narrower components as the BW encounters dense equatorial ring (ER) material. Even so, continuing v-b emission is seen in the grating spectra suggesting that the interaction with H II region material is ongoing. Based on the deep HETG 2007 and 2011 data sets, and confirmed by RGS and other HETG observations, the v-b component has a width of 9300 {+-} 2000 km s{sup -1} FWHM and contributes of order 20% of the current 0.5-2 keV flux. Guided by this result, SN 1987A's X-ray spectra are modeled as the weighted sum of the non-equilibrium-ionization emission from two simple one-dimensional hydrodynamic simulations; this '2 Multiplication-Sign 1D' model reproduces the observed radii, light curves, and spectra with a minimum of free parameters. The interaction with the H II region ({rho}{sub init} Almost-Equal-To 130 amu cm{sup -3}, {+-} 15 Degree-Sign opening angle) produces the very broad emission lines and most of the 3-10 keV flux. Our ER hydrodynamics, admittedly a crude approximation to the multi-D reality, gives ER densities of {approx}10{sup 4} amu cm{sup -3}, requires dense clumps ( Multiplication-Sign 5.5 density enhancement in {approx}30% of the volume), and predicts that the 0.5-2 keV flux will drop at a rate of {approx}17% per year once no new dense ER material is being shocked.
Jaume Garriga; Alexander Vilenkin
1997-07-26T23:59:59.000Z
If the effective cosmological constant is non-zero, our observable universe may enter a stage of exponential expansion. In such case, regions of it may tunnel back to the false vacuum of an inflaton scalar field, and inflation with a high expansion rate may resume in those regions. An ``ideal'' eternal observer would then witness an infinite succession of cycles from false vacuum to true, and back. Within each cycle, the entire history of a hot universe would be replayed. If there were several minima of the inflaton potential, our ideal observer would visit each one of these minima with a frequency which depends on the shape of the potential. We generalize the formalism of stochastic inflation to analyze the global structure of the universe when this `recycling' process is taken into account.
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Northern Arizona University Wind Projects | Open Energy Information
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University of Dayton Research Institute | Open Energy Information
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da Costa, Fatima Rubio; Petrosian, Vahe'; Carlsson, Mats
2015-01-01T23:59:59.000Z
Solar flares involve complex processes that are coupled together and span a wide range of temporal, spatial, and energy scales. Modeling such processes self-consistently has been a challenge in the past. Here we present such a model to simulate the coupling of high-energy particle kinetics with hydrodynamics of the atmospheric plasma. We combine the Stanford unified Fokker-Planck code that models particle acceleration, transport, and bremsstrahlung radiation with the RADYN hydrodynamic code that models the atmospheric response to collisional heating by non-thermal electrons through detailed radiative transfer calculations. We perform simulations using different injection electron spectra, including an {\\it ad hoc} power law and more realistic spectra predicted by the stochastic acceleration model due to turbulence or plasma waves. Surprisingly, stochastically accelerated electrons, even with energy flux $\\ll 10^{10}$ erg s$^{-1}$ cm$^{-2}$, cause "explosive" chromospheric evaporation and drive stronger up- an...
Srinivasan, Bhuvana, E-mail: srinbhu@vt.edu [Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Department of Aerospace and Ocean Engineering, Virginia Tech, Blacksburg, Virginia 24061 (United States); Tang, Xian-Zhu, E-mail: xtang@lanl.gov [Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
2014-10-15T23:59:59.000Z
In an inertial confinement fusion target, energy loss due to thermal conduction from the hot-spot will inevitably ablate fuel ice into the hot-spot, resulting in a more massive but cooler hot-spot, which negatively impacts fusion yield. Hydrodynamic mix due to Rayleigh-Taylor instability at the gas-ice interface can aggravate the problem via an increased gas-ice interfacial area across which energy transfer from the hot-spot and ice can be enhanced. Here, this mix-enhanced transport effect on hot-spot fusion-performance degradation is quantified using contrasting 1D and 2D hydrodynamic simulations, and its dependence on effective acceleration, Atwood number, and ablation speed is identified.
Ahn, Hyung-Joon; Bang, Young-Seok; Kim, In-Goo; Kim, Hho-Jung [Regulatory Research Div., Korea Institute of Nuclear Safety, 19 Kusongdong Yusongku Taejon (Korea, Republic of); Lee, Byeong-Eun; Kwon, Soon-Bum [School of Mech. Eng., Kyungpook National University, 1370, Sankyuk-dong, Puk-ku, Daegu 702-701 (Korea, Republic of)
2002-07-01T23:59:59.000Z
The In-containment Refueling Water Storage Tank (IRWST) has the function of heat sink when steam is released from the pressurizer. The hydrodynamic behaviors occurring at the sparger are very complex because of the wide variety of operating conditions and the complex geometry. Hydrodynamic behavior when air is discharged through a sparger in a condensation pool is investigated using CFD techniques in the present study. The effect of pressure acting on the sparger header during both water and air discharge through the sparger is studied. In addition, pressure oscillation occurring during air discharge through the sparger is studied for a better understanding of mechanisms of air discharge and a better design of the IRWST, including sparger. (authors)
Santiago, Juan G.
focusing microfluidic mixer for protein folding Benjamin Ivorra, Juana L. Redondo, Juan G. Santiago, Pilar of a fast hydrodynamic focusing microfluidic mixer for protein folding Benjamin Ivorra,1,a) Juana L. Redondo
Cope, David M. (David Michael)
2012-01-01T23:59:59.000Z
Hydrodynamic flow visualization techniques of scaled hull forms and propellers are typically limited to isolating certain operating conditions in a tow tank, circulation tunnel, or large maneuvering basin. Although cost ...
Three-dimensional hydrodynamic simulations of the combustion of a neutron star into a quark star
Matthias Herzog; Friedrich K. Roepke
2011-09-02T23:59:59.000Z
We present three-dimensional numerical simulations of turbulent combustion converting a neutron star into a quark star. Hadronic matter, described by a micro-physical finite-temperature equation of state, is converted into strange quark matter. We assume this phase, represented by a bag-model equation of state, to be absolutely stable. Following the example of thermonuclear burning in white dwarfs leading to Type Ia supernovae, we treat the conversion process as a potentially turbulent deflagration. Solving the non-relativistic Euler equations using established numerical methods we conduct large eddy simulations including an elaborate subgrid scale model, while the propagation of the conversion front is modeled with a level-set method. Our results show that for large parts of the parameter space the conversion becomes turbulent and therefore significantly faster than in the laminar case. Despite assuming absolutely stable strange quark matter, in our hydrodynamic approximation an outer layer remains in the hadronic phase, because the conversion front stops when it reaches conditions under which the combustion is no longer exothermic.
Two-Dimensional Hydrodynamic Models of Super Star Clusters with a Positive Star Formation Feedback
Wünsch, R; Palous, J; Silich, S
2008-01-01T23:59:59.000Z
Using the hydrodynamic code ZEUS, we perform 2D simulations to determine the fate of the gas ejected by massive stars within super star clusters. It turns out that the outcome depends mainly on the mass and radius of the cluster. In the case of less massive clusters, a hot high velocity ($\\sim 1000$ km s$^{-1}$) stationary wind develops and the metals injected by supernovae are dispersed to large distances from the cluster. On the other hand, the density of the thermalized ejecta within massive and compact clusters is sufficiently large as to immediately provoke the onset of thermal instabilities. These deplete, particularly in the central densest regions, the pressure and the pressure gradient required to establish a stationary wind, and instead the thermally unstable parcels of gas are rapidly compressed, by a plethora of re-pressurizing shocks, into compact high density condensations. Most of these are unable to leave the cluster volume and thus accumulate to eventually feed further generations of star for...
Tom Chang; Cheng-chin Wu; Marius Echim; Herve Lamy; Mark Vogelsberger; Lars Hernquist; Debora Sijacki
2014-02-26T23:59:59.000Z
Dynamic Complexity is a phenomenon exhibited by a nonlinearly interacting system within which multitudes of different sizes of large scale coherent structures emerge, resulting in a globally nonlinear stochastic behavior vastly different from that could be surmised from the underlying equations of interaction. The hallmark of such nonlinear, complex phenomena is the appearance of intermittent fluctuating events with the mixing and distributions of correlated structures at all scales. We briefly review here a relatively recent method, ROMA (rank-ordered multifractal analysis), explicitly constructed to analyze the intricate details of the distribution and scaling of such types of intermittent structures. This method is then applied to the analyses of selected examples related to the dynamical plasmas of the cusp region of the magnetosphere, velocity fluctuations of classical hydrodynamic turbulence, and the distribution of the structures of the cosmic gas obtained through large scale, moving mesh simulations. Differences and similarities of the analyzed results among these complex systems will be contrasted and highlighted. The first two examples have direct relevance to the geospace environment and are summaries of previously reported findings. The third example on the cosmic gas, though involving phenomena much larger in spatiotemporal scales, with its highly compressible turbulent behavior and the unique simulation technique employed in generating the data, provides direct motivations of applying such analysis to studies of similar multifractal processes in various extreme environments. These new results are both exciting and intriguing.
Radiative hydrodynamic modelling and observations of the X-class solar flare on 2011 March 9
Kennedy, Michael B; Allred, Joel C; Mathioudakis, Mihalis; Keenan, Francis P
2015-01-01T23:59:59.000Z
We investigated the response of the solar atmosphere to non-thermal electron beam heating using the radiative transfer and hydrodynamics modelling code RADYN. The temporal evolution of the parameters that describe the non-thermal electron energy distribution were derived from hard X-ray observations of a particular flare, and we compared the modelled and observed parameters. The evolution of the non-thermal electron beam parameters during the X1.5 solar flare on 2011 March 9 were obtained from analysis of RHESSI X-ray spectra. The RADYN flare model was allowed to evolve for 110 seconds, after which the electron beam heating was ended, and was then allowed to continue evolving for a further 300s. The modelled flare parameters were compared to the observed parameters determined from extreme-ultraviolet spectroscopy. The model produced a hotter and denser flare loop than that observed and also cooled more rapidly, suggesting that additional energy input in the decay phase of the flare is required. In the explosi...
Sekiguchi, Yuichiro; Kyutoku, Koutarou; Shibata, Masaru
2015-01-01T23:59:59.000Z
We perform radiation-hydrodynamics simulations of binary neutron star mergers in numerical relativity on the Japanese "K" supercomputer, taking into account neutrino cooling and heating by an updated leakage-plus-transfer scheme for the first time. Neutron stars are modeled by three modern finite-temperature equations of state (EOS) developed by Hempel and his collaborators. We find that the electron fraction has a broad distribution due to the weak processes and shock heating. The properties of the ejecta such as total mass, average electron fraction, and thermal energy depend strongly on the EOS. Only for a soft EOS (the so-called SFHo), the ejecta mass exceeds $0.01M_{\\odot}$. In this case, the electron fraction has a broad distribution which is well-suited for the production of the solar-like $r$-process abundance. For the other stiff EOS (DD2 and TM1), for which a long-lived massive neutron star is formed after the merger, the ejecta mass is smaller than $0.01M_{\\odot}$, although broad electron-fraction ...
Abundance anomalies in metal-poor stars from Population III supernova ejecta hydrodynamics
Sluder, Alan; Safranek-Shrader, Chalence; Milosavljevic, Milos; Bromm, Volker
2015-01-01T23:59:59.000Z
We present a simulation of the long-term evolution of a Population III supernova remnant in a cosmological minihalo. Employing passive Lagrangian tracer particles, we investigate how chemical stratification and anisotropy in the explosion can affect the abundances of the first low-mass, metal-enriched stars. We find that reverse shock heating can leave the inner mass shells at entropies too high to cool, leading to carbon-enhancement in the re-collapsing gas. This hydrodynamic selection effect could explain the observed incidence of carbon-enhanced metal-poor (CEMP) stars at low metallicity. We further explore how anisotropic ejecta distributions, recently seen in direct numerical simulations of core-collapse explosions, may translate to abundances in metal-poor stars. We find that some of the observed scatter in the Population II abundance ratios can be explained by an incomplete mixing of supernova ejecta, even in the case of only one contributing enrichment event. We demonstrate that the customary hypothes...
HEAVY DUST OBSCURATION OF z = 7 GALAXIES IN A COSMOLOGICAL HYDRODYNAMIC SIMULATION
Kimm, Taysun; Cen, Renyue [Department of Astrophysical Sciences, Princeton University, Peyton Hall, Princeton, NJ 08544 (United States)
2013-10-10T23:59:59.000Z
Hubble Space Telescope observations with the Wide Field Camera 3/Infrared reveal that galaxies at z ? 7 have very blue ultraviolet (UV) colors, consistent with these systems being dominated by young stellar populations with moderate or little attenuation by dust. We investigate UV and optical properties of the high-z galaxies in the standard cold dark matter model using a high-resolution adaptive mesh refinement cosmological hydrodynamic simulation. For this purpose, we perform panchromatic three-dimensional dust radiative transfer calculations on 198 galaxies of stellar mass 5 × 10{sup 8}-3 × 10{sup 10} M{sub ?} with three parameters: the dust-to-metal ratio, the extinction curve, and the fraction of directly escaped light from stars (f{sub esc}). Our stellar mass function is found to be in broad agreement with Gonzalez et al., independent of these parameters. We find that our heavily dust-attenuated galaxies (A{sub V} ? 1.8) can also reasonably match modest UV-optical colors, blue UV slopes, as well as UV luminosity functions, provided that a significant fraction (?10%) of light directly escapes from them. The observed UV slope and scatter are better explained with a Small-Magellanic-Cloud-type extinction curve, whereas a Milky-Way-type curve also predicts blue UV colors due to the 2175 Å bump. We expect that upcoming observations by the Atacama Large Millimeter/submillimeter Array will be able to test this heavily obscured model.
A Module for Radiation Hydrodynamic Calculations With ZEUS-2D Using Flux-Limited Diffusion
N. J. Turner; J. M. Stone
2001-02-08T23:59:59.000Z
A module for the ZEUS-2D code is described which may be used to solve the equations of radiation hydrodynamics to order unity in v/c, in the flux-limited diffusion (FLD) approximation. In this approximation, the tensor Eddington factor f which closes the radiation moment equations is chosen to be an empirical function of radiation energy density. This is easier to implement and faster than full-transport techniques, in which f is computed by solving the transfer equation. However, FLD is less accurate when the flux has a component perpendicular to the gradient in radiation energy density, and in optically thin regions when the radiation field depends strongly on angle. The material component of the fluid is here assumed to be in local thermodynamic equilibrium. The energy equations are operator-split, with transport terms, radiation diffusion term, and other source terms evolved separately. Transport terms are applied using the same consistent transport algorithm as in ZEUS-2D. The radiation diffusion term is updated using an alternating-direction implicit method with convergence checking. Remaining source terms are advanced together implicitly using numerical root-finding. However when absorption opacity is zero, accuracy is improved by treating compression and expansion source terms using time-centered differencing. Results are discussed for test problems including radiation-damped linear waves, radiation fronts propagating in optically-thin media, subcritical and supercritical radiating shocks, and an optically-thick shock in which radiation dominates downstream pressure.
Thermo-Hydrodynamics of Circumstellar Disks with High-mass Planets
Gennaro D'Angelo; Thomas Henning; Willy Kley
2003-09-08T23:59:59.000Z
With a series of numerical simulations, we analyze the thermo-hydrodynamical evolution of circumstellar disks containing Jupiter-size protoplanets. In the framework of the two-dimensional approximation, we consider an energy equation that includes viscous heating and radiative effects in a simplified, yet consistent form. Multiple nested grids are used in order to study both global and local features around the planet. By means of different viscosity prescriptions, we investigate various temperature regimes. A planetary mass range from 0.1 to 1 Mj is examined. Computations show that gap formation is a general property which affects density, pressure, temperature, optical thickness, and radiated flux distributions. However, it remains a prominent feature only when the kinematic viscosity is on the order of 10^(15) cm^2/s or lower. Around accreting planets, a circumplanetary disk forms that has a surface density profile decaying exponentially with the distance and whose mass is 5-6 orders of magnitudes smaller than Jupiter's mass. Circumplanetary disk temperature profiles decline roughly as the inverse of the distance from the planet. Temperatures range from some 10 to ~1000 K. Planetary accretion and migration rates depend on the viscosity regime, with discrepancies within an order of magnitude. Estimates of growth and migration time scales inferred by these models are on the same orders of magnitude as those previously obtained with locally isothermal simulations.
Smolt Responses to Hydrodynamic Conditions in Forebay Flow Nets of Surface Flow Outlets, 2007
Johnson, Gary E.; Richmond, Marshall C.; Hedgepeth, J. B.; Ploskey, Gene R.; Anderson, Michael G.; Deng, Zhiqun; Khan, Fenton; Mueller, Robert P.; Rakowski, Cynthia L.; Sather, Nichole K.; Serkowski, John A.; Steinbeck, John R.
2009-04-01T23:59:59.000Z
This study provides information on juvenile salmonid behaviors at McNary and The Dalles dams that can be used by the USACE, fisheries resource managers, and others to support decisions on long-term measures to enhance fish passage. We researched smolt movements and ambient hydrodynamic conditions using a new approach combining simultaneous acoustic Doppler current profiler (ADCP) and acoustic imaging device (AID) measurements at surface flow outlets (SFO) at McNary and The Dalles dams on the Columbia River during spring and summer 2007. Because swimming effort vectors could be computed from the simultaneous fish and flow data, fish behavior could be categorized as passive, swimming against the flow (positively rheotactic), and swimming with the flow (negatively rheotactic). We present bivariate relationships to provide insight into fish responses to particular hydraulic variables that engineers might consider during SFO design. The data indicate potential for this empirical approach of simultaneous water/fish measurements to lead to SFO design guidelines in the future.
Design of an electromagnetic accelerator for turbulent hydrodynamic mix studies. Revision 1
Susoeff, A.R.; Hawke, R.S.; Morrison, J.J.; Dimonte, G.; Remington, B.A.
1994-03-01T23:59:59.000Z
An electromagnetic accelerator in the form of a linear electric motor (LEM) has been designed to achieve controlled acceleration profiles of a carriage containing hydrodynamically unstable fluids for the investigation of the development of turbulent mix. Key features of the design include: (1) independent control of acceleration, deceleration and augmentation currents to provide a variety of acceleration-time profiles, (2) a robust support structure to minimized deflection and dampen vibration which could create artifacts in the data interfering with the intended study and (3) a compliant, non-arcing solid armature allowing optimum electrical contact. Electromagnetic modeling codes were used to optimize the rail and augmentation coil positions within the support structure framework. Design of the driving armature and the dynamic electromagnetic braking system is based on results of contemporary studies for non-arcing sliding contact of solid armatures. A 0.6MJ electrolytic capacitor bank is used for energy storage to drive the LEM. This report will discuss a LEM and armature design which will accelerate masses of up to 3kg to a maximum of about 3000g{sub o}, where g{sub o} is acceleration due to gravity.
Yanbiao Gan; Aiguo Xu; Guangcai Zhang; Sauro Succi
2015-05-11T23:59:59.000Z
A discrete Boltzmann model (DBM) is developed to investigate the hydrodynamic and thermodynamic non-equilibrium (TNE) effects in phase separation processes. The interparticle force drives changes and the gradient force, induced by gradients of macroscopic quantities, opposes them. In this paper, we investigate the interplay between them by providing detailed inspection of various non-equilibrium observables. Based on the TNE features, we define a TNE strength which roughly estimates the deviation amplitude from the thermodynamic equilibrium. The time evolution of the TNE intensity provides a convenient and efficient physical criterion to discriminate the stages of the spinodal decomposition and domain growth. Via the DBM simulation and this criterion, we quantitatively study the effects of latent heat and surface tension on phase separation. It is found that, the TNE strength attains its maximum at the end of the spinodal decomposition stage, and it decreases when the latent heat increases from zero. The surface tension effects are threefold, to prolong the duration of the spinodal decomposition stage, decrease the maximum TNE intensity, and accelerate the speed of the domain growth stage.
Khangaonkar, Tarang; Yang, Zhaoqing
2011-01-01T23:59:59.000Z
Estuarine and coastal hydrodynamic processes are sometimes neglected in the design and planning of nearshore restoration actions. Despite best intentions, efforts to restore nearshore habitats can result in poor outcomes if circulation and transport which also affect freshwater-saltwater interactions are not properly addressed. Limitations due to current land use can lead to selection of sub-optimal restoration alternatives that may result in undesirable consequences, such as flooding, deterioration of water quality, and erosion, requiring immediate remedies and costly repairs. Uncertainty with achieving restoration goals, such as recovery of tidal exchange, supply of sediment and nutrients, and establishment of fish migration pathways, may be minimized by using numerical models designed for application to the nearshore environment. A high resolution circulation and transport model of the Puget Sound, in the state of Washington, was developed to assist with nearshore habitat restoration design and analysis, and to answer the question “can we achieve beneficial restoration outcomes at small local scale, as well as at a large estuary-wide scale?” The Puget Sound model is based on an unstructured grid framework to define the complex Puget Sound shoreline using a finite volume coastal ocean model (FVCOM). The capability of the model for simulating the important nearshore processes, such as circulation in complex multiple tidal channels, wetting and drying of tide flats, and water quality and sediment transport as part of restoration feasibility, are illustrated through examples of restoration projects in Puget Sound.