University of Maine Hydrodynamics | Open Energy Information
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Oregon State University Hydrodynamics | Open Energy Information
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Pennsylvania State University Hydrodynamics | Open Energy Information
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University of Michigan 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 on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaP a g eWorks -09-0018-CXNuonYuchengRichlands,project activitiesCommerceUniversity of Michigan
University of Minnesota 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 on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaP a g eWorks -09-0018-CXNuonYuchengRichlands,project activitiesCommerceUniversity of
University of New Hampshire 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 on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaP a g eWorks -09-0018-CXNuonYuchengRichlands,project activitiesCommerceUniversity ofInformation
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.
On the universal identity in second order hydrodynamics
Sašo Grozdanov; Andrei O. Starinets
2014-12-29T23:59:59.000Z
We compute the 't Hooft coupling correction to the infinite coupling expression for the second order transport coefficient $\\lambda_2$ in ${\\cal N}=4$ $SU(N_c)$ supersymmetric Yang-Mills theory at finite temperature in the limit of infinite $N_c$, which originates from the $R^4$ terms in the low energy effective action of the dual type IIB string theory. Using this result, we show that the identity involving the three second order transport coefficients, $2 \\eta \\tau_\\Pi - 4 \\lambda_1 - \\lambda_2 =0$, previously shown by Haack and Yarom to hold universally in relativistic conformal field theories with string dual descriptions to leading order in supergravity approximation, holds also at next to leading order in this theory. We also compute corrections to transport coefficients in a (hypothetical) strongly interacting conformal fluid arising from the generic curvature squared terms in the corresponding dual gravity action (in particular, Gauss-Bonnet action), and show that the identity holds to linear order in the higher-derivative couplings. We discuss potential implications of these results for the near-equilibrium entropy production rate at strong coupling.
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...
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 ...
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
RIDGE JUMP PROCESS IN ICELAND Sebastian GARCIA
Paris-Sud XI, UniversitÃ© de
1 RIDGE JUMP PROCESS IN ICELAND Sebastian GARCIA Freie UniversitÃ¤t Berlin Â Department of Geologie, sgarcia@zedat.fu-berlin.de Abstract Eastward ridge jumps bring the volcanic zones of Iceland back pulses triggers these ridge jumps. One of them is occurring in Southern Iceland, whereas the exact
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
Revisiting the emission from relativistic blast waves in a density-jump medium
Geng, J. J.; Huang, Y. F.; Dai, Z. G. [School of Astronomy and Space Science, Nanjing University, Nanjing 210093 (China); Wu, X. F. [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China); Li, Liang, E-mail: hyf@nju.edu.cn, E-mail: dzg@nju.edu.cn, E-mail: xfwu@pmo.ac.cn [Department of Physics, Stockholm University, AlbaNova, SE-106 91 Stockholm (Sweden)
2014-09-01T23:59:59.000Z
Re-brightening bumps are frequently observed in gamma-ray burst afterglows. Many scenarios have been proposed to interpret the origin of these bumps, of which a blast wave encountering a density-jump in the circumburst environment has been questioned by recent works. We develop a set of differential equations to calculate the relativistic outflow encountering the density-jump by extending the work of Huang et al. This approach is a semi-analytic method and is very convenient. Our results show that late high-amplitude bumps cannot be produced under common conditions, rather only a short plateau may emerge even when the encounter occurs at an early time (<10{sup 4} s). In general, our results disfavor the density-jump origin for those observed bumps, which is consistent with the conclusion drawn from full hydrodynamics studies. The bumps thus should be caused by other scenarios.
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.
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...
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
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.
Side-Jump Effect in Paramagnetic Amorphous Metals
RHIE, K.; Naugle, Donald G.; O, BH; MARKERT, JT.
1993-01-01T23:59:59.000Z
VOLUME 48, NUMBER 9 1 SEPTEMBER 1993-I Side-jump effect in paramagnetic amorphous metals K. Rhie and D. G. Naugle Department of Physics, Texas Ad'cM University, College Station, Texas 77843 424-2 Beom-hoan 0 and J. T. Markert Department of.... INTRODUCTION RsdH ?a[dN, (e)/de j ~, 2eN, (eF), Many amorphous metallic alloys have positive Hall coefficients (RH). Positive values of RH are found for some amorphous rare-earth-based alloys, weak ferromag- netic alloys, early-transition-metal (ETM...
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 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
Hydrodynamic interactions in colloidal crystals
Weeber, Rudolf
2011-01-01T23:59:59.000Z
In dense colloids it is commonly assumed that hydrodynamic interactions do not play a role. However, a found theoretical quantification is often missing. We present computer simulations that are motivated by experiments where a large colloidal particle is dragged through a colloidal crystal. To qualify the influence of long-ranged hydrodynamics, we model the setup by conventional Langevin dynamics simulations and by an improved scheme with limited hydrodynamic interactions. This scheme significantly improves our results and allows to show that hydrodynamics strongly impacts on the development of defects, the crystal regeneration as well as on the jamming behavior.
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.
Lifshitz Superfluid Hydrodynamics
Shira Chapman; Carlos Hoyos; Yaron Oz
2014-10-09T23:59:59.000Z
We construct the first order hydrodynamics of quantum critical points with Lifshitz scaling and a spontaneously broken symmetry. The fluid is described by a combination of two flows, a normal component that carries entropy and a super-flow which has zero viscosity and carries no entropy. We analyze the new transport effects allowed by the lack of boost invariance and constrain them by the local second law of thermodynamics. Imposing time-reversal invariance, we find eight new parity even transport coefficients. The formulation is applicable, in general, to any superfluid/superconductor with an explicit breaking of boost symmetry, in particular to high $T_c$ superconductors. We discuss possible experimental signatures.
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
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...
Jump-Diffusion Risk-Sensitive Asset Management II: Jump-Diffusion Factor Model
Davis, Mark
2011-01-01T23:59:59.000Z
In this article we extend earlier work on the jump-diffusion risk-sensitive asset management problem [SIAM J. Fin. Math. (2011) 22-54] by allowing jumps in both the factor process and the asset prices, as well as stochastic volatility and investment constraints. In this case, the HJB equation is a partial integro-differential equation (PIDE). By combining viscosity solutions with a change of notation, a policy improvement argument and classical results on parabolic PDEs we prove that the HJB PIDE admits a unique smooth solution. A verification theorem concludes the resolution of this problem.
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...
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.
Formation Interuniversitaire de Physique Hydrodynamics
Balbus, Steven
. . . . . . . . . . . . . . . . . . 12 2.3 Energy Equation for a Gas . . . . . . . . . . . . . . . . . . . . 13 2.4 Adiabatic Equations Waves . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 4.2.1 Hydraulic Jumps . . . . . . . . . . . . . . . . . . . . . . . . 55 4.6 Group Velocity . . . . . . . . . . . . . . . . . . . . . . . . . . 57 4.7 Wave Energy
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.
Universal Ownership: Why Environmental Externalities Matter to...
Universal Ownership: Why Environmental Externalities Matter to Institutional Investors Jump to: navigation, search Tool Summary LAUNCH TOOL Name: Universal Ownership: Why...
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...
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...
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 on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaP a g eWorks - AsTorrington, Wyoming (UtilityMeasures (TRANSfer) | OpenBebidas LtdaColorado
Cornell 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 on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaP a g eWorks - AsTorrington, Wyoming (UtilityMeasuresPage Edit HistoryCoos-CurryWashington)Cornell
2003-01-01T23:59:59.000Z
Boeke, K. , Cosmic View: The Universe in 40 Jumps, John DayTime Travel in Einstein’s Universe, p 175, Houghton Mi?in,Fig. 7. — Pocket map of the universe Fig. 8a. — Map of the
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
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
Millifluidics: Capillarity and Interfacial Hydrodynamics
Bico,José
Millifluidics: Capillarity and Interfacial Hydrodynamics José Bico PMMH-ESPCI-ParisTech-P6-P7 www Pa ~ 10-2 atm cavitation bubble: R ~ 0.5 !m, # ~ 50 mN/m $P ~ 105 Pa ~ 1 atm He bubbles (irradiated
An implicit numerical algorithm general relativistic hydrodynamics
A. Hujeirat
2008-01-09T23:59:59.000Z
An implicit numerical algorithm general relativistic hydrodynamics This article has been replaced by arXiv:0801.1017
Hamilton-Jacobi equations with jumps: asymptotic stability
Amir Mahmood; Saima Parveen
2009-09-05T23:59:59.000Z
The asymptotic stability of a global solution satisfying Hamilton-Jacobi equations with jumps will be analyzed in dependence on the strong dissipativity of the jump control function and using orbits of the differentiable flows to describe the corresponding characteristic system.
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
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
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
Smooth Light Curves from a Bumpy Ride: Relativistic Blast Wave Encounters a Density Jump
Nakar, Ehud; /Caltech; Granot, Jonathan; /KIPAC, Menlo Park
2006-06-06T23:59:59.000Z
Some gamma-ray burst (GRB) afterglow light curves show significant variability, which often includes episodes of rebrightening. Such temporal variability had been attributed in several cases to large fluctuations in the external density, or density ''bumps''. Here we carefully examine the effect of a sharp increase in the external density on the afterglow light curve by considering, for the first time, a full treatment of both the hydrodynamic evolution and the radiation in this scenario. To this end we develop a semi-analytic model for the light curve and carry out several elaborate numerical simulations using a one dimensional hydrodynamic code together with a synchrotron radiation code. Two spherically symmetric cases are explored in detail--a density jump in a uniform external medium, and a wind termination shock. The effect of density clumps is also constrained. Contrary to previous works, we find that even a very sharp (modeled as a step function) and large (by a factor of a >> 1) increase in the external density does not produce sharp features in the light curve, and cannot account for significant temporal variability in GRB afterglows. For a wind termination shock, the light curve smoothly transitions between the asymptotic power laws over about one decade in time, and there is no rebrightening in the optical or X-rays that could serve as a clear observational signature. For a sharp jump in a uniform density profile we find that the maximal deviation {Delta}{alpha}{sub max} of the temporal decay index {alpha} from its asymptotic value (at early and late times), is bounded (e.g, {Delta}{alpha}{sub max} < 0.4 for {alpha} = 10); {Delta}{alpha}{sub max} slowly increases with {alpha}, converging to {Delta}{alpha}{sub max} {approx} 1 at very large {alpha} values. Therefore, no optical rebrightening is expected in this case as well. In the X-rays, while the asymptotic flux is unaffected by the density jump, the fluctuations in {alpha} are found to be comparable to those in the optical. Finally, we discuss the implications of our results for the origin of the observed fluctuations in several GRB afterglows.
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.
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:...
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...
Some open questions in hydrodynamics
Mateusz Dyndal; Laurent Schoeffel
2014-12-16T23:59:59.000Z
When speaking of unsolved problems in physics, this is surprising at first glance to discuss the case of fluid mechanics. However, there are many deep open questions that come with the theory of fluid mechanics. In this paper, we discuss some of them that we classify in two categories, the long term behavior of solutions of equations of hydrodynamics and the definition of initial (boundary) conditions. The first set of questions come with the non-relativistic theory based on the Navier-Stokes equations. Starting from smooth initial conditions, the purpose is to understand if solutions of Navier-Stokes equations remain smooth with the time evolution. Existence for just a finite time would imply the evolution of finite time singularities, which would have a major influence on the development of turbulent phenomena. The second set of questions come with the relativistic theory of hydrodynamics. There is an accumulating evidence that this theory may be relevant for the description of the medium created in high energy heavy-ion collisions. However, this is not clear that the fundamental hypotheses of hydrodynamics are valid in this context. Also, the determination of initial conditions remains questionable. The purpose of this paper is to explore some ideas related to these questions, both in the non-relativistic and relativistic limits of fluid mechanics. We believe that these ideas do not concern only the theory side but can also be useful for interpreting results from experimental measurements.
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 ...
Spontaneous azimuthal breakout and instability at the circular hydraulic jump
Ray, Arnab K; Basu, Abhik; Bhattacharjee, Jayanta K
2015-01-01T23:59:59.000Z
We consider a shallow, two-dimensional flow of a liquid in which the radial and the azimuthal dynamics are coupled to each other. The steady and radial background flow of this system creates an axially symmetric circular hydraulic jump. On this background we apply time-dependent perturbations of the matter flow rate and the azimuthal flow velocity, with the latter strongly localized at the hydraulic jump. The perturbed variables depend spatially on both the radial and azimuthal coordinates. Linearization of the perturbations gives a coupled system of wave equations. The characteristic equations extracted from these wave equations show that under a marginally stable condition a spontaneous breaking of axial symmetry occurs at the position of the hydraulic jump. Departure from the marginal stability shows further that a linear instability develops in the azimuthal direction, resulting in an azimuthal transport of liquid at the hydraulic jump. The time for the growth of azimuthal instability is scaled by viscosi...
Chemical Potential Jump during Evaporation of a Quantum Bose Gas
E. A. Bedrikova; A. V. Latyshev
2013-01-07T23:59:59.000Z
The dependence of the chemical potential jump coefficient on the evaporation coefficient is analyzed for the case in which the evaporating component is a Bose gas. The concentration of the evaporating component is assumed to be much lower than the concentration of the carrier gas. The expression for the chemical potential jump is derived from the analytic solution of the problem for the case in which the collision frequency of molecules of the evaporating component is constant.
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.
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.
COMBINED MODELING OF ACCELERATION, TRANSPORT, AND HYDRODYNAMIC...
Office of Scientific and Technical Information (OSTI)
Search Title: COMBINED MODELING OF ACCELERATION, TRANSPORT, AND HYDRODYNAMIC RESPONSE IN SOLAR FLARES. I. THE NUMERICAL MODEL Acceleration and transport of high-energy particles...
Hydrodynamic experiment conducted in Nevada | National Nuclear...
National Nuclear Security Administration (NNSA)
that mimic many of the properties of nuclear materials. Hydrodynamics refers to the physics involved when solids, under extreme conditions, begin to mix and flow like liquids....
Collision-dominated nonlinear hydrodynamics in graphene
Briscot, U; Gornyi, I V; Titov, M; Narozhny, B N; Mirlin, A D
2015-01-01T23:59:59.000Z
We present an effective hydrodynamic theory of electronic transport in graphene in the interaction-dominated regime. We derive the emergent hydrodynamic description from the microscopic Boltzmann kinetic equation taking into account dissipation due to Coulomb interaction and find the viscosity of Dirac fermions in graphene for arbitrary densities. The viscous terms have a dramatic effect on transport coefficients in clean samples at high temperatures. Within linear response, we show that viscosity manifests itself in the nonlocal conductivity as well as dispersion of hydrodynamic plasmons. Beyond linear response, we apply the derived nonlinear hydrodynamics to the problem of hot spot relaxation in graphene.
Effects on the Physical Environment (Hydrodynamics, Sediment...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Sediment Transport, and Water Quality) Effects on the Physical Environment (Hydrodynamics, Sediment Transport, and Water Quality) Effects on the Physical Environment...
Hydrodynamics on non-commutative space --A step toward hydrodynamics of granular materials--
Mayumi Saitou; Kazuharu Bamba; Akio Sugamoto
2014-09-16T23:59:59.000Z
Hydrodynamics on non-commutative space is studied based on a formulation of hydrodynamics by Y. Nambu in terms of Poisson and Nambu brackets. Replacing these brackets by Moyal brackets with a parameter $\\theta$, a new hydrodynamics on non-commutative space is derived. It may be a step toward to find the hydrodynamics of granular materials whose minimum volume is given by $\\theta$. To clarify this minimum volume, path integral quantization and uncertainty relation of Nambu dynamics are examined.
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).
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.
Hydrodynamic enhanced dielectrophoretic particle trapping
Miles, Robin R.
2003-12-09T23:59:59.000Z
Hydrodynamic enhanced dielectrophoretic particle trapping carried out by introducing a side stream into the main stream to squeeze the fluid containing particles close to the electrodes producing the dielelectrophoretic forces. The region of most effective or the strongest forces in the manipulating fields of the electrodes producing the dielectrophoretic forces is close to the electrodes, within 100 .mu.m from the electrodes. The particle trapping arrangement uses a series of electrodes with an AC field placed between pairs of electrodes, which causes trapping of particles along the edges of the electrodes. By forcing an incoming flow stream containing cells and DNA, for example, close to the electrodes using another flow stream improves the efficiency of the DNA trapping.
Hydrodynamics and phases of flocks
Toner, John [Institute of Theoretical Science, Department of Physics, University of Oregon, Eugene, OR 97403-5203 (United States); Tu Yuhai [IBM T. J. Watson Research Center, P.O. Box 218, Yorktown Heights, NY 10598 (United States)]. E-mail: yuhai@us.ibm.com; Ramaswamy, Sriram [Centre for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore 560012 (India)
2005-07-01T23:59:59.000Z
We review the past decade's theoretical and experimental studies of flocking: the collective, coherent motion of large numbers of self-propelled 'particles' (usually, but not always, living organisms). Like equilibrium condensed matter systems, flocks exhibit distinct 'phases' which can be classified by their symmetries. Indeed, the phases that have been theoretically studied to date each have exactly the same symmetry as some equilibrium phase (e.g., ferromagnets, liquid crystals). This analogy with equilibrium phases of matter continues in that all flocks in the same phase, regardless of their constituents, have the same 'hydrodynamic'-that is, long-length scale and long-time behavior, just as, e.g., all equilibrium fluids are described by the Navier-Stokes equations. Flocks are nonetheless very different from equilibrium systems, due to the intrinsically nonequilibrium self-propulsion of the constituent 'organisms'. This difference between flocks and equilibrium systems is most dramatically manifested in the ability of the simplest phase of a flock, in which all the organisms are, on average moving in the same direction (we call this a 'ferromagnetic' flock; we also use the terms 'vector-ordered' and 'polar-ordered' for this situation) to exist even in two dimensions (i.e., creatures moving on a plane), in defiance of the well-known Mermin-Wagner theorem of equilibrium statistical mechanics, which states that a continuous symmetry (in this case, rotation invariance, or the ability of the flock to fly in any direction) can not be spontaneously broken in a two-dimensional system with only short-ranged interactions. The 'nematic' phase of flocks, in which all the creatures move preferentially, or are simply oriented preferentially, along the same axis, but with equal probability of moving in either direction, also differs dramatically from its equilibrium counterpart (in this case, nematic liquid crystals). Specifically, it shows enormous number fluctuations, which actually grow with the number of organisms faster than the N 'law of large numbers' obeyed by virtually all other known systems. As for equilibrium systems, the hydrodynamic behavior of any phase of flocks is radically modified by additional conservation laws. One such law is conservation of momentum of the background fluid through which many flocks move, which gives rise to the 'hydrodynamic backflow' induced by the motion of a large flock through a fluid. We review the theoretical work on the effect of such background hydrodynamics on three phases of flocks-the ferromagnetic and nematic phases described above, and the disordered phase in which there is no order in the motion of the organisms. The most surprising prediction in this case is that 'ferromagnetic' motion is always unstable for low Reynolds-number suspensions. Experiments appear to have seen this instability, but a quantitative comparison is awaited. We conclude by suggesting further theoretical and experimental work to be done.
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.
Analysis and Improvements of Fringe Jump Corrections by Electronics on the JET Tokamak FIR Interferometer
Effects on the Physical Environment (Hydrodynamics, and Water...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
on the Physical Environment (Hydrodynamics, and Water Quality Food Web) Effects on the Physical Environment (Hydrodynamics, and Water Quality Food Web) Effects on the Physical...
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
Peak-Jumping Frequent Itemset Mining Nele Dexters1
Van Gucht, Dirk
Peak-Jumping Frequent Itemset Mining Algorithms Nele Dexters1 , Paul W. Purdom2 , and Dirk Van Gucht2 1 Departement Wiskunde-Informatica, Universiteit Antwerpen, Belgium, nele.dexters@ua.ac.be, 2. We analyze algorithms that, under the right circumstances, permit efficient mining for frequent
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
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.
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.
Shear viscosity, cavitation and hydrodynamics at LHC
Bhatt, Jitesh R; Sreekanth, V
2011-01-01T23:59:59.000Z
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.
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.
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
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.
Fast MCMC sampling for Markov jump processes and extensions
Bach, Francis
Fast MCMC sampling for Markov jump processes and extensions Vinayak Rao and Yee Whye Teh Rao-backward, Baum-Welch. V Rao and Y W Teh (Mar 2013) Fast MCMC for MJPs 2 / 41 #12;Continuous-Time Hidden Markov state i V Rao and Y W Teh (Mar 2013) Fast MCMC for MJPs 3 / 41 #12;Predator-Prey (Lotka-Volterra) Model
Non-hydrodynamic transport in trapped unitary Fermi gases
Jasmine Brewer; Paul Romatschke
2015-08-05T23:59:59.000Z
Many strongly coupled fluids are known to share similar hydrodynamic transport properties. In this work we argue that this similarity could extend beyond hydrodynamics to transient dynamics through the presence of non-hydrodynamic modes. We review non-hydrodynamic modes in kinetic theory and gauge/gravity duality and discuss their signatures in trapped Fermi gases close to unitarity. Reanalyzing previously published experimental data, we find hints of non-hydrodynamic modes in cold Fermi gases in two and three dimensions.
Non-hydrodynamic transport in trapped unitary Fermi gases
Brewer, Jasmine
2015-01-01T23:59:59.000Z
Many strongly coupled fluids are known to share similar hydrodynamic transport properties. In this work we argue that this similarity could extend beyond hydrodynamics to transient dynamics through the presence of non-hydrodynamic modes. We review non-hydrodynamic modes in kinetic theory and gauge/gravity duality and discuss their signatures in trapped Fermi gases close to unitarity. Reanalyzing previously published experimental data, we find hints of non-hydrodynamic modes in cold Fermi gases in two and three dimensions.
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.
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...
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
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
Edit: Study -APP Save | Exit | Hide/Show Errors | Print... | Jump To
Biederman, Irving
Edit: Study - APP Save | Exit | Hide/Show Errors | Print... | Jump To: 01. Project Guidance Save | Exit | Hide/Show Errors | Print... | Jump To: 01. Project IdentificationStarDev/ResourceAdministration/Project/ProjectEditor?Project=com... 1 #12;Edit: Study - APP- Save | Exit | Hide/Show Errors | Print... | Jump To: 02. Study
Jump Flooding in GPU with Applications to Voronoi Diagram and Distance Transform Guodong Rong
Tan, Tiow Seng
Jump Flooding in GPU with Applications to Voronoi Diagram and Distance Transform Guodong Rong Tiow of the jump flooding algorithm is shown in the other six pictures, with the rightmost being the computed Voronoi diagram. Abstract This paper studies jump flooding as an algorithmic paradigm in the general
NUMERICAL STUDY OF A TURBULENT HYDRAULIC JUMP Qun Zhao 1 Shubhra K. Misra1
Zhao, Qun
. Hydraulic jumps are commonly used as energy dissipators and they have been studied intensively by hydraulicNUMERICAL STUDY OF A TURBULENT HYDRAULIC JUMP Qun Zhao 1 Shubhra K. Misra1 Ib A. Svendsen 1 (Member of a turbulent hydraulic jump. The numerical model is based on RIPPLE (Kothe et al., 1994) with two turbulence
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.
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.
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.
Computing the Rates of Measurement-Induced Quantum Jumps
Michel Bauer; Denis Bernard; Antoine Tilloy
2015-06-08T23:59:59.000Z
Small quantum systems can now be continuously monitored experimentally which allows for the reconstruction of quantum trajectories. A peculiar feature of these trajectories is the emergence of jumps between the eigenstates of the observable which is measured. Using the Stochastic Master Equation (SME) formalism for continuous quantum measurements, we show that the density matrix of a system indeed shows a jumpy behavior when it is subjected to a tight measurement (even if the noise in the SME is Gaussian). We are able to compute the jump rates analytically for any system evolution, i.e. any Lindbladian, and we illustrate how our general recipe can be applied to two simple examples. We then discuss the mathematical, foundational and practical applications of our results. The analysis we present is based on a study of the strong noise limit of a class of stochastic differential equations (the SME) and as such the method may be applicable to other physical situations in which a strong noise limit plays a role.
Hydrodynamic analysis of mooring lines based on optical tracking experiments
Yang, Woo Seuk
2009-05-15T23:59:59.000Z
Due to the complexity of body-shape, the investigation of hydrodynamic forces on mooring lines, especially those comprised of chain segments, has not been conducted to a sufficient degree to properly characterize the hydrodynamic damping effect...
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
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.
Dilepton production in schematic causal viscous hydrodynamics
Song, Taesoo; Han, Kyong Chol; Ko, Che Ming.
2011-01-01T23:59:59.000Z
transversal to the reaction plane, we derive a set of schematic equations from the Isreal-Stewart causal viscous hydrodynamics. These equations are then used to describe the evolution dynamics of relativistic heavy-ion collisions by taking the shear viscosity...
Adiabatic hydrodynamics: The eightfold way to dissipation
Felix M. Haehl; R. Loganayagam; Mukund Rangamani
2015-03-17T23:59:59.000Z
We provide a complete solution to hydrodynamic transport at all orders in the gradient expansion compatible with the second law constraint. The key new ingredient we introduce is the notion of adiabaticity, which allows us to take hydrodynamics off-shell. Adiabatic fluids are such that off-shell dynamics of the fluid compensates for entropy production. The space of adiabatic fluids is quite rich, and admits a decomposition into seven distinct classes. Together with the dissipative class this establishes the eightfold way of hydrodynamic transport. Furthermore, recent results guarantee that dissipative terms beyond leading order in the gradient expansion are agnostic of the second law. While this completes a transport taxonomy, we go on to argue for a new symmetry principle, an Abelian gauge invariance that guarantees adiabaticity in hydrodynamics. We suggest that this symmetry is the macroscopic manifestation of the microscopic KMS invariance. We demonstrate its utility by explicitly constructing effective actions for adiabatic transport. The theory of adiabatic fluids, we speculate, provides a useful starting point for a new framework to describe non-equilibrium dynamics, wherein dissipative effects arise by Higgsing the Abelian symmetry.
HYDRODYNAMICS OF UNDULATORY PROPULSION GEORGE V. LAUDER
Lauder, George V.
of a quantitative nature. The combination of highresolution highspeed video systems, high powered continuous wave11 HYDRODYNAMICS OF UNDULATORY PROPULSION GEORGE V. LAUDER ERIC D. TYTELL I. Introduction II. Classical Modes of Undulatory Propulsion III. Theory of Undulatory Propulsion A. Resistive Models B
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.
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.
Hydrodynamic Tesla Wheel Flume for Model and Prototype Testing
Wood, Stephen L.
Hydrodynamic 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, hydrodynamic, laminar, fluid, flow, model, prototype testing, Tesla wheel. I. INTRODUCTION The southeast region
Hydrodynamic Flow Patterns and Synchronization of Beating Cilia Andrej Vilfan*
Jülicher, Frank
Hydrodynamic Flow Patterns and Synchronization of Beating Cilia Andrej Vilfan* J. Stefan Institute 2006) We calculate the hydrodynamic flow field generated far from a cilium which is attached to a surface and beats periodically. In the case of two beating cilia, hydrodynamic interactions can lead
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.
Effective Hydrodynamic Boundary Conditions for Corrugated Surfaces
Mongruel, Anne; Asmolov, Evgeny S; Vinogradova, Olga I
2012-01-01T23:59:59.000Z
We report measurements of the hydrodynamic drag force acting on a smooth sphere falling down under gravity to a plane decorated with microscopic periodic grooves. Both surfaces are lyophilic, so that a liquid (silicone oil) invades the surface texture being in the Wenzel state. A significant decrease in the hydrodynamic resistance force as compared with that predicted for two smooth surfaces is observed. To quantify the effect of roughness we use the effective no-slip boundary condition, which is applied at the imaginary smooth homogeneous isotropic surface located at an intermediate position between top and bottom of grooves. Such an effective condition fully characterizes the force reduction measured with the real surface, and the location of this effective plane is related to geometric parameters of the texture by a simple analytical formula.
Heat capacity of liquids: A hydrodynamic approach
T. Bryk; T. Scopigno; G. Ruocco
2015-04-06T23:59:59.000Z
We study autocorrelation functions of energy, heat and entropy densities obtained by molecular dynamics simulations of supercritical Ar and compare them with the predictions of the hydrodynamic theory. It is shown that the predicted by the hydrodynamic theory single-exponential shape of the entropy density autocorrelation functions is perfectly reproduced for small wave numbers by the molecular dynamics simulations and permits the calculation of the wavenumber-dependent specific heat at constant pressure. The estimated wavenumber-dependent specific heats at constant volume and pressure, $C_{v}(k)$ and $C_{p}(k)$, are shown to be in the long-wavelength limit in good agreement with the macroscopic experimental values of $C_{v}$ and $C_{p}$ for the studied thermodynamic points of supercritical Ar.
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.
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 on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County, Pennsylvania:1975 | OpenMaplewoodMartin'sMascoma Corp JumpMassachusetts
Hydrodynamic Interactions of Self-Propelled Swimmers
John J. Molina; Yasuya Nakayama; Ryoichi Yamamoto
2013-01-12T23:59:59.000Z
The hydrodynamic interactions of a suspension of self-propelled particles are studied using a direct numerical simulation method which simultaneously solves for the host fluid and the swimming particles. A modified version of the "Smoothed Profile" method (SPM) is developed to simulate microswimmers as squirmers, which are spherical particles with a specified surface-tangential slip velocity between the particles and the fluid. This simplified swimming model allows one to represent different types of propulsion (pullers and pushers) and is thus ideal to study the hydrodynamic interactions among swimmers. We use the SPM to study the diffusive behavior which arises due to the swimming motion of the particles, and show that there are two basic mechanisms responsible for this phenomena: the hydrodynamic interactions caused by the squirming motion of the particles, and the particle-particle collisions. This dual nature gives rise to two distinct time- and length- scales, and thus to two diffusion coefficients, which we obtain by a suitable analysis of the swimming motion. We show that the collisions between swimmers can be interpreted in terms of binary collisions, in which the effective collision radius is reduced due to the collision dynamics of swimming particles in viscous fluids. At short time-scales, the dynamics of the swimmer is analogous to that of an inert tracer particle in a swimming suspension, in which the diffusive motion is caused by fluid-particle collisions. Our results, along with the simulation method we have introduced, will allow us to gain a better understanding of the complex hydrodynamic interactions of self-propelled swimmers.
Notes 00. Introduction to Hydrodynamic Lubrication
San Andres, Luis
2010-01-01T23:59:59.000Z
Tribology needs for the 2000?s Dr. Luis San Andres August 2010 Other applications: Sports equipment: compliant, durable, tough, better performance (less friction and less wear) Medicine: Hip-joint replacements, miniature pumps for fluid injection.../removal, heart pumps and implants, 1 MRPM dental hand drills Ultra-hard drilling equipment: no wear and tear, i.e. infinite life Surface engineering, materials. Surface engineering, materials, lubricants. Gas hydrodynamics Nanopowder coatings, Surface engineering...
HydrodynamicallyBased Overshoot Treatment and Nucleosynthesis
HydrodynamicallyÂBased Overshoot Treatment and Nucleosynthesis in AGB Stars F. Herwig 1 , T. Bl dominated by 12 C. This leads to the nucleosynthesis of 13 C via 12 C(p; fl) 13 N(fi; + Å¡) 13 C and is probÂ ably the major source of neutrons ( 13 C(ff; n) 16 O) for subsequent sÂprocess nucleosynthesis. We
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
Ferguson, Thomas S.
. Blogs Winter 2015 Internship Search Wednesday, January 7, 4-7pm Engineering / Technology / Consulting-7pm Graduate Student JumpStart Engineering and Technology Thursday, Oct 16, 4-7pm #12;
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...
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
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...
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
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
., Song, A., and Wang, A. (2013). A bio-inspired jumping robot: Modeling, simulation, design, and experimental results. Mechatronics 23, 1123–1140. 25. Churaman, W.A., Gerratt, A.P., and Bergbreiter, S. (2011). First leaps toward jumping microrobots...
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 on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaP a g eWorks - As Prepared forChoice Electric CoEurusGansuHelianthosHonda Soltec CoHydroGen Jump
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.
Hydrodynamic experiment provides key data for Stockpile Stewardship
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
experiments such as Leda involve non-nuclear surrogate materials that mimic many of the properties of nuclear materials. December 22, 2014 Los Alamos hydrodynamic experiment...
Compressible hydrodynamic flow of liquid crystals in 1-D
2009-08-17T23:59:59.000Z
We consider the equation modeling the compressible hydrodynamic flow ... In this paper, we consider the one dimensional initial-boundary value problem for.
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...
Supernova Hydrodynamics on the Omega Laser
R. Paul Drake
2004-01-16T23:59:59.000Z
(B204)The fundamental motivation for our work is that supernovae are not well understood. Recent observations have clarified the depth of our ignorance, by producing observed phenomena that current theory and computer simulations cannot reproduce. Such theories and simulations involve, however, a number of physical mechanisms that have never been studied in isolation. We perform experiments, in compressible hydrodynamics and radiation hydrodynamics, relevant to supernovae and supernova remnants. These experiments produce phenomena in the laboratory that are believed, based on simulations, to be important to astrophysics but that have not been directly observed in either the laboratory or in an astrophysical system. During the period of this grant, we have focused on the scaling of an astrophysically relevant, radiative-precursor shock, on preliminary studies of collapsing radiative shocks, and on the multimode behavior and the three-dimensional, deeply nonlinear evolution of the Rayleigh-Taylor (RT) instability at a decelerating, embedded interface. These experiments required strong compression and decompression, strong shocks (Mach {approx}10 or greater), flexible geometries, and very smooth laser beams, which means that the 60-beam Omega laser is the only facility capable of carrying out this program.
RESEARCH ARTICLE Hydrodynamic sensing and behavior by oyster larvae in
Fuchs, Heidi L.
were achieved through an increase in propulsive force and power output that would carry a highRESEARCH ARTICLE Hydrodynamic sensing and behavior by oyster larvae in turbulence and waves Heidi L Hydrodynamic signals from turbulence and waves may provide marine invertebrate larvae with behavioral cues
LINEAR STABILITY OF ELECTRON-FLOW HYDRODYNAMICS IN UNGATED SEMICONDUCTORS
Sen, Mihir
LINEAR STABILITY OF ELECTRON-FLOW HYDRODYNAMICS IN UNGATED SEMICONDUCTORS A Dissertation Submitted All Rights Reserved #12;LINEAR STABILITY OF ELECTRON-FLOW HYDRODYNAMICS IN UNGATED SEMICONDUCTORS Abstract by Williams R. CalderÂ´on Mu~noz Semiconductors play an important role in modern electronic
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.
Hydrodynamic models for slurry bubble column reactors
Gidaspow, D. [IIT Center, Chicago, IL (United States)
1995-12-31T23:59:59.000Z
The objective of this investigation is to convert a {open_quotes}learning gas-solid-liquid{close_quotes} fluidization model into a predictive design model. This model is capable of predicting local gas, liquid and solids hold-ups and the basic flow regimes: the uniform bubbling, the industrially practical churn-turbulent (bubble coalescence) and the slugging regimes. Current reactor models incorrectly assume that the gas and the particle hold-ups (volume fractions) are uniform in the reactor. They must be given in terms of empirical correlations determined under conditions that radically differ from reactor operation. In the proposed hydrodynamic approach these hold-ups are computed from separate phase momentum balances. Furthermore, the kinetic theory approach computes the high slurry viscosities from collisions of the catalyst particles. Thus particle rheology is not an input into the model.
Hydrodynamical random walker with chemotactic memory
H. Mohammady; B. Esckandariun; A. Najafi
2014-10-01T23:59:59.000Z
A three-dimensional hydrodynamical model for a micro random walker is combined with the idea of chemotactic signaling network of E. coli. Diffusion exponents, orientational correlation functions and their dependence on the geometrical and dynamical parameters of the system are analyzed numerically. Because of the chemotactic memory, the walker shows superdiffusing displacements in all directions with the largest diffusion exponent for a direction along the food gradient. Mean square displacements and orientational correlation functions show that the chemotactic memory washes out all the signatures due to the geometrical asymmetry of the walker and statistical properties are asymmetric only with respect to the direction of food gradient. For different values of the memory time, the Chemotactic index (CI) is also calculated.
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.
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.
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.
Numeric spectral radiation hydrodynamic calculations of supernova shock breakouts
Sapir, Nir; Halbertal, Dorri [Department of Particle Physics and Astrophysics, Weizmann Institute of Science, Rehovot 76100 (Israel)
2014-12-01T23:59:59.000Z
We present here an efficient numerical scheme for solving the non-relativistic one-dimensional radiation-hydrodynamics equations including inelastic Compton scattering, which is not included in most codes and is crucial for solving problems such as shock breakout. The devised code is applied to the problems of a steady-state planar radiation mediated shock (RMS) and RMS breakout from a stellar envelope. The results are in agreement with those of a previous work on shock breakout, in which Compton equilibrium between matter and radiation was assumed and the 'effective photon' approximation was used to describe the radiation spectrum. In particular, we show that the luminosity and its temporal dependence, the peak temperature at breakout, and the universal shape of the spectral fluence derived in this earlier work are all accurate. Although there is a discrepancy between the spectral calculations and the effective photon approximation due to the inaccuracy of the effective photon approximation estimate of the effective photon production rate, which grows with lower densities and higher velocities, the difference in peak temperature reaches only 30% for the most discrepant cases of fast shocks in blue supergiants. The presented model is exemplified by calculations for supernova 1987A, showing the detailed evolution of the burst spectrum. The incompatibility of the stellar envelope shock breakout model results with observed properties of X-ray flashes (XRFs) and the discrepancy between the predicted and observed rates of XRFs remain unexplained.
Testing for jumps in the context of high frequency data Universite P. et M. Curie (Paris-6)
Testing for jumps in the context of high frequency data Jean Jacod Universit´e P. et M. Curie are not (the drift, the law of the jumps). Then we propose a test to decide, on the basis of the discrete components to our process, we also give a test about whether the two components jump at the same time or not
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
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
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 ...
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...
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 ...
Quantum Darwinism, Decoherence, and the Randomness of Quantum Jumps
Zurek, Wojciech H. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2014-06-05T23:59:59.000Z
Tracing flows of information in our quantum Universe explains why we see the world as classical. Quantum principle of superposition decrees every combination of quantum states a legal quantum state. This is at odds with our experience. Decoherence selects preferred pointer states that survive interaction with the environment. They are localized and effectively classical. They persist while their superpositions decohere. Here we consider emergence of `the classical' starting at a more fundamental pre-decoherence level, tracing the origin of preferred pointer states and deducing their probabilities from the core quantum postulates. We also explore role of the environment as medium through which observers acquire information. This mode of information transfer leads to perception of objective classical reality.
Hydrodynamical Description of the QCD Dirac Spectrum at Finite Chemical Potential
Liu, Yizhuang; Zahed, Ismail
2015-01-01T23:59:59.000Z
We present a hydrodynamical description of the QCD Dirac spectrum at finite chemical potential as an uncompressible droplet in the complex eigenvalue space. For a large droplet, the fluctuation spectrum around the hydrostatic solution is gapped by a longitudinal Coulomb plasmon, and exhibits a frictionless odd viscosity. The stochastic relaxation time for the restoration/breaking of chiral symmetry is set by twice the plasmon frequency. The leading droplet size correction to the relaxation time is fixed by a universal odd viscosity to density ratio $\\eta_O/\\rho_0=(\\beta-1)/2$ for the three Dyson ensembles $\\beta=1,2,4$.
Hydrodynamic limit in a particle system with topological interactions
Giardinà, Cristian
of the rightmost occupied site requires a knowledge of the entire configuration and prevents from using correlation an exponential time of mean 1 to the nearest neighbor sites, the jumps leading outside [0, -1] being suppressed
Triangular flow in hydrodynamics and transport theory
Alver, Burak Han [Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139-4307 (United States); Gombeaud, Clement; Luzum, Matthew; Ollitrault, Jean-Yves [CNRS, URA2306, IPhT, Institut de physique theorique de Saclay, F-91191 Gif-sur-Yvette (France)
2010-09-15T23:59:59.000Z
In ultrarelativistic heavy-ion collisions, the Fourier decomposition of the relative azimuthal angle, {Delta}{phi}, distribution of particle pairs yields a large cos(3{Delta}{phi}) component, extending to large rapidity separations {Delta}{eta}>1. This component captures a significant portion of the ridge and shoulder structures in the {Delta}{phi} distribution, which have been observed after contributions from elliptic flow are subtracted. An average finite triangularity owing to event-by-event fluctuations in the initial matter distribution, followed by collective flow, naturally produces a cos(3{Delta}{phi}) correlation. Using ideal and viscous hydrodynamics and transport theory, we study the physics of triangular (v{sub 3}) flow in comparison to elliptic (v{sub 2}), quadrangular (v{sub 4}), and pentagonal (v{sub 5}) flow. We make quantitative predictions for v{sub 3} at RHIC and LHC as a function of centrality and transverse momentum. Our results for the centrality dependence of v{sub 3} show a quantitative agreement with data extracted from previous correlation measurements by the STAR collaboration. This study supports previous results on the importance of triangular flow in the understanding of ridge and shoulder structures. Triangular flow is found to be a sensitive probe of initial geometry fluctuations and viscosity.
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.
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.
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...
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...
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...
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...
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 ...
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)...
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 ...
Universal Lighting Technologies | Open Energy Information
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Fluctuating hydrodynamics of multispecies mixtures. I. Non-reacting Flows Kaushik Balakrishnan,1
Bell, John B.
of hydrodynamic fluctuations is not restricted to mesoscale phenomena. Laboratory experiments involving gases
Fluctuating hydrodynamics approach to equilibrium time correlations for anharmonic chains
Herbert Spohn
2015-05-22T23:59:59.000Z
Linear fluctuating hydrodynamics is a useful and versatile tool for describing fluids, as well as other systems with conserved fields, on a mesoscopic scale. In one spatial dimension, however, transport is anomalous, which requires to develop a nonlinear extension of fluctuating hydrodynamics. The relevant nonlinearity turns out to be the quadratic part of the Euler currents when expanding relative to a uniform background. We outline the theory and compare with recent molecular dynamics simulations.
A new three-dimensional general-relativistic hydrodynamics code
Luca Baiotti; Ian Hawke; Pedro J. Montero; Luciano Rezzolla
2010-04-22T23:59:59.000Z
We present a new three-dimensional general relativistic hydrodynamics code, the Whisky code. This code incorporates the expertise developed over the past years in the numerical solution of Einstein equations and of the hydrodynamics equations in a curved spacetime, and is the result of a collaboration of several European Institutes. We here discuss the ability of the code to carry out long-term accurate evolutions of the linear and nonlinear dynamics of isolated relativistic stars.
Sedimentation of pairs of hydrodynamically interacting semiflexible filaments
Isaac Llopis; Ignacio Pagonabarraga; Marco Cosentino Lagomarsino; Christopher P. Lowe
2007-10-08T23:59:59.000Z
We describe the effect of hydrodynamic interactions in the sedimentation of a pair of inextensible semiflexible filaments under a uniform constant force at low Reynolds numbers. We have analyzed the different regimes and the morphology of such polymers in simple geometries, which allow us to highlight the peculiarities of the interplay between elastic and hydrodynamic stresses. Cooperative and symmetry breaking effects associated to the geometry of the fibers gives rise to characteristic motion which give them distinct properties from rigid and elastic filaments.
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.
University Park, Florida: Energy Resources | Open Energy Information
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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.
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.
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.
Hydrodynamic construction of the electromagnetic field
Peter Holland
2014-10-03T23:59:59.000Z
We present an alternative Eulerian hydrodynamic model for the electromagnetic field in which the discrete vector indices in Maxwell\\s equations are replaced by continuous angular freedoms, and develop the corresponding Lagrangian picture in which the fluid particles have rotational and translational freedoms. This enables us to extend to the electromagnetic field the exact method of state construction proposed previously for spin 0 systems, in which the time-dependent wavefunction is computed from a single-valued continuum of deterministic trajectories where two spacetime points are linked by at most a single orbit. The deduction of Maxwell\\s equations from continuum mechanics is achieved by generalizing the spin 0 theory to a general Riemannian manifold from which the electromagnetic construction is extracted as a special case. In particular, the flat-space Maxwell equations are represented as a curved-space Schr\\"odinger equation for a massive system. The Lorentz covariance of the Eulerian field theory is obtained from the non-covariant Lagrangian-coordinate model as a kind of collective effect. The method makes manifest the electromagnetic analogue of the quantum potential that is tacit in Maxwell\\s equations. This implies a novel definition of the \\classical limit\\ of Maxwell\\s equations that differs from geometrical optics. It is shown that Maxwell\\s equations may be obtained by canonical quantization of the classical model. Using the classical trajectories a novel expression is derived for the propagator of the electromagnetic field in the Eulerian picture. The trajectory and propagator methods of solution are illustrated for the case of a light wave.
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.
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.
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
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
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
Usefulness of the reversible jump Markov chain Monte Carlo model in regional flood frequency
Ribatet, Mathieu
Usefulness of the reversible jump Markov chain Monte Carlo model in regional flood frequency; revised 3 May 2007; accepted 17 May 2007; published 3 August 2007. [1] Regional flood frequency analysis and the index flood approach. Results show that the proposed estimator is absolutely suited to regional
Shanghai University | Open Energy Information
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Murdoch University | Open Energy Information
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Uppsala University | Open Energy Information
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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 $1/(4\\pi)$.
Hydrodynamic Correlations slow down Crystallization of Soft Colloids
Roehm, Dominic; Arnold, Axel
2013-01-01T23:59:59.000Z
Crystallization is often assumed to be a quasi-static process that is unaffected by details of particle transport other than the bulk diffusion coefficient. Therefore colloidal suspensions are frequently argued to be an ideal toy model for experimentally more difficult systems such as metal melts. In this letter, we want to challenge this assumption. To this aim, we have considered molecular dynamics simulations of the crystallization in a suspension of Yukawa-type colloids. In order to investigate the role of hydrodynamic interactions (HIs) mediated by the solvent, we modeled the solvent both implicitly and explicitly, using Langevin dynamics and the fluctuating Lattice Boltzmann method, respectively. Our simulations show a dramatic reduction of the crystal growth velocity due to HIs even at moderate hydrodynamic coupling. A detailed analysis shows that this slowdown is due to the wall-like properties of the crystal surface, which reduces the colloidal diffusion towards the crystal surface by hydrodynamic sc...
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...
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.
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.
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.
Anisotropic hydrodynamics for mixture of quark and gluon fluids
Florkowski, Wojciech; Ryblewski, Radoslaw; Tinti, Leonardo
2015-01-01T23:59:59.000Z
A system of equations for anisotropic hydrodynamics is derived that describes a mixture of anisotropic quark and gluon fluids. The consistent treatment of the zeroth, first and second moments of the kinetic equations allows us to construct a new framework with more general forms of the anisotropic phase-space distribution functions than those used before. In this way, the main difficiencies of the previous formulations of anisotropic hydrodynamics for mixtures have been overcome and the good agreement with the exact kinetic-theory results is obtained.
Accounting for backflow in hydrodynamic-simulation interfaces
Scott Pratt
2014-01-01T23:59:59.000Z
Methods for building a consistent interface between hydrodynamic and simulation modules is presented. These methods account for the backflow across the hydrodynamic/simulation hyper-surface. The algorithms are efficient, relatively straight-forward to implement, and account for conservation laws across the hyper-surface. The methods also account for the spurious interactions between particles in the backflow and other particles by following the subsequent impact of such particles. Since the number of altered trajectories grows exponentially in time, a cutoff is built into the procedure so that the effects of the backflow are ignored beyond a certain number of collisions
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
Benedict, Joshua King
2011-01-01T23:59:59.000Z
For the hydrodynamic feature analyzed full cavitation wassignificant cavitation affects as well as hydrodynamic loadcavitation is maintained across the area of this particular macro/micro-feature, an increase in hydrodynamic
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.
Martone, Patrick T.
VARIATION IN ANATOMICAL AND MATERIAL PROPERTIES EXPLAINS DIFFERENCES IN HYDRODYNAMIC PERFORMANCES that material properties of seaweed tissues may influence their fitness. Because hydrodynamic forces are likely difficult to disentangle the effects of materials properties on seaweed performance because size, shape
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, ...
Self-Similar Radiation-Hydrodynamics Solutions in the Equilibrium Diffusion Limit
Lane, Taylor Kinsey
2013-01-31T23:59:59.000Z
, radiation, and shock waves. These phenomena can be found in supernovae explosions, or in inertial confinement fusion applications. Hydrodynamics Model To begin to understand the complex flows involved with RHD, it is important to first consider hydrodynamics...
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
Palanker, Daniel
Multifocal laser surgery: Cutting enhancement by hydrodynamic interactions between cavitation a single cavitation bubble. We investigate the hydrodynamic interactions between simultaneous cavitation bubbles originating from multiple laser foci. Simultaneous expansion and collapse of cavitation bubbles
Quasi-two Dimensional Hydrodynamics and Interaction of Vortex Tubes
Zakharov, Vladimir
Quasi-two Dimensional Hydrodynamics and Interaction of Vortex Tubes Vladimir Zakharov 1 but a careful study of the dynamics of the vortex tubes or their systems in a real 3-dimentional nonstationary for description of this type of flow looks very timely. Another motivation is the vortex dynamics
Linearly resummed hydrodynamics in a weakly curved spacetime
Yanyan Bu; Michael Lublinsky
2015-02-27T23:59:59.000Z
We extend our study of all-order linearly resummed hydrodynamics in a flat space~\\cite{1406.7222,1409.3095} to fluids in weakly curved spaces. The underlying microscopic theory is a finite temperature $\\mathcal{N}=4$ super-Yang-Mills theory at strong coupling. The AdS/CFT correspondence relates black brane solutions of the Einstein gravity in asymptotically \\emph{locally} $\\textrm{AdS}_5$ geometry to relativistic conformal fluids in a weakly curved 4D background. To linear order in the amplitude of hydrodynamic variables and metric perturbations, the fluid's energy-momentum tensor is computed with derivatives of both the fluid velocity and background metric resummed to all orders. We extensively discuss the meaning of all order hydrodynamics by expressing it in terms of the memory function formalism, which is also suitable for practical simulations. In addition to two viscosity functions discussed at length in refs.~\\cite{1406.7222,1409.3095}, we find four curvature induced structures coupled to the fluid via new transport coefficient functions. In ref.~\\cite{0905.4069}, the latter were referred to as gravitational susceptibilities of the fluid. We analytically compute these coefficients in the hydrodynamic limit, and then numerically up to large values of momenta.
Generalised hydrodynamic reductions of the kinetic equation for soliton gas
Generalised hydrodynamic reductions of the kinetic equation for soliton gas Gennady A. El1 , Maxim of Russian Academy of Sciences, Moscow, 53 Leninskij Prospekt, Moscow, Russia 3 Laboratory of Geometric, Moscow, Russia 4 Institute for Nuclear Research, National Academy of Sciences of Ukraine, 47 pr. Nauky
Sedimentation, Pclet number, and hydrodynamic screening Kiley Benes,1
Tong, Penger
Sedimentation, Péclet number, and hydrodynamic screening Kiley Benes,1 Penger Tong,2 and Bruce J January 2007; revised manuscript received 7 May 2007; published 8 November 2007 The sedimentation of hard. Two functional forms for the sedimentation velocity as a function of particle concen- tration
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...
CHARACTERIZATION OF SURFACE ROUGHNESS AND INITIAL CONDITIONS FOR CYLINDRICAL HYDRODYNAMIC
Barnes, Cris W.
CHARACTERIZATION OF SURFACE ROUGHNESS AND INITIAL CONDITIONS FOR CYLINDRICAL HYDRODYNAMIC AND MIX across a variable density interface, that interface must be well characterized. There exist a number, characterizing, and affecting the surface roughness was driven by Ablative Rayleigh-Taylor work5
Smoothed Particle Hydrodynamics and Magnetohydrodynamics Daniel J. Price
Price, Daniel
Smoothed Particle Hydrodynamics and Magnetohydrodynamics Daniel J. Price Centre for Stellar reviews already exist (e.g. Monaghan, 1992, 2005; Price, 2004; Rosswog, 2009), there remain particularly of the otherwise unpublished material in my PhD thesis (Price, 2004). Email address: daniel.price
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.
Event-by-event hydrodynamics: A better tool to study the Quark-Gluon plasma
Grassi, Frederique [Instituto de Fisica, Universidade de Sao Paulo (Brazil)
2013-03-25T23:59:59.000Z
Hydrodynamics has been established as a good tool to describe many data from relativistic heavyion collisions performed at RHIC and LHC. More recently, it has become clear that it is necessary to use event-by-event hydrodynamics (i.e. describe each collision individually using hydrodynamics), an approach first developed in Brazil. In this paper, I review which data require the use of event-by-event hydrodynamics and what more we may learn on the Quark-Gluon Plasma with this.
University of Michigan | 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 on Google Bookmark EERE: Alternative Fuels Data Center Home Page onsource History View NewUS National Fuel Cell Research Center NFCRC JumpUniversal LightingUniversity ofUniversity
University of North Carolina | 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 on Google Bookmark EERE: Alternative Fuels Data Center Home Page onsource History View NewUS National Fuel Cell Research Center NFCRC JumpUniversal LightingUniversityUniversity of North
University of South Florida | 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 on Google Bookmark EERE: Alternative Fuels Data Center Home Page onsource History View NewUS National Fuel Cell Research Center NFCRC JumpUniversal LightingUniversityUniversity of
University of Washington | 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 on Google Bookmark EERE: Alternative Fuels Data Center Home Page onsource History View NewUS National Fuel Cell Research Center NFCRC JumpUniversal LightingUniversityUniversity
Dmytro Oliinychenko; Hannah Petersen
2015-08-18T23:59:59.000Z
Many hybrid models of heavy ion collisions construct the initial state for hydrodynamics from transport models. Hydrodynamics requires that the energy-momentum tensor $T^{\\mu\
Oliinychenko, Dmytro
2015-01-01T23:59:59.000Z
Many hybrid models of heavy ion collisions construct the initial state for hydrodynamics from transport models. Hydrodynamics requires that the energy-momentum tensor $T^{\\mu\
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.
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
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 investigated during recent years,1-5 little is known about the chemical consequences of hydrodynamic cavitation resulted from hydrodynamic cavitation within the fluidizer.11 We describe here conclusive experimental
University Heights, Ohio: Energy Resources | 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 on Google Bookmark EERE: Alternative Fuels Data Center Home Page onsource History View NewUS National Fuel Cell Research Center NFCRC JumpUniversal Lighting Technologies Jump
Harrington, Deborah Lea
2014-01-01T23:59:59.000Z
You Can't Just Jump Into the Icy Pool of Metacognition": TheYou Can't Just Jump Into the Icy Pool of Metacognition": Thejump into the icy pool of metacognition. ” This
Pulsed power hydrodynamics : a new application of high magnetic fields.
Reinovsky, R. E. (Robert E.); Anderson, W. E. (Wallace E.); Atchison, W. L. (Walter L.); Faehl, R. J. (Rickey J.); Keinigs, R. K. (Rhonald K.); Lindemuth, I. R.; Scudder, D. W. (David W.); Shlachter, Jack S.; Taylor, Antoinette J.,
2002-01-01T23:59:59.000Z
Pulsed Power Hydrodynamics is a new application of high magnetic fields recently developed to explore advanced hydrodynamics, instabilities, fluid turbulences, and material properties in a highly precise, controllable environment at the extremes of pressure and material velocity. The Atlas facility at Los Alamos is the world's first and only laboratory pulsed power system designed specifically to explore this relatively new family of megagauss magnetic field applications. Constructed in 2000 and commissioned in August 2001, Atlas is a 24-MJ high-performance capacitor bank delivering up to 30 MA with a current risetime of 5-6 {micro}sec. The high-precision, cylindrical, imploding liner is the tool most frequently used to convert electrical energy into the hydrodynamic (particle kinetic) energy needed to drive the experiments. For typical liner parameters including initial radius of 5 cm, the peak current of 30 MA delivered by Atlas results in magnetic fields just over 1 MG outside the liner prior to implosion. During the 5 to 10-{micro}sec implosion, the field outside the liner rises to several MG in typical situations. At these fields the rear surface of the liner is melted and it is subject to a variety of complex behaviors including: diffusion dominated andor melt wave field penetration and heating, magneto Raleigh-Taylor sausage mode behavior at the liner/field interface, and azimuthal asymmetry due to perturbations in current drive. The first Atlas liner implosion experiments were conducted in September 2000 and 10-15 experiments are planned in the: first year of operation. Immediate applications of the new pulsed power hydrodynamics techniques include material property topics including: exploration of material strength at high rates of strain, material failure including fracture and spall, and interfacial dynamics at high relative velocities and high interfacial pressures. A variety of complex hydrodynamic geometries will be explored and experiments will be designed to explore uristable perturbation growth and transition to turbulence. This paper will provide an overview of the range of problems to which pulsed power hydrodynamics can be applied and the issues associated with these techniques. Other papers at this Conference will present specifics of individual experiments and elaborate on the liner physics issues.
Sidorov, Nikita
· "Granular jets and hydraulic jumps on an inclined plane", C. G. Johnson, J. M. N. T. Gray ( ), J material impinging on an inclined plane pro- duces a diverse range of ows, from steady hydraulic jumps-moving radial ow, surrounded by either a teardrop-shaped, or a `blunted' hydraulic jump. A depth
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.
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 ...
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...
A new hydrodynamics code for Type Ia Supernovae
Leung, S -C; Lin, L -M
2015-01-01T23:59:59.000Z
A two-dimensional hydrodynamics code for Type Ia supernovae (SNIa) simulations is presented. The code includes a fifth-order shock-capturing scheme WENO, detailed nuclear reaction network, flame-capturing scheme and sub-grid turbulence. For post-processing we have developed a tracer particle scheme to record the thermodynamical history of the fluid elements. We also present a one-dimensional radiative transfer code for computing observational signals. The code solves the Lagrangian hydrodynamics and moment-integrated radiative transfer equations. A local ionization scheme and composition dependent opacity are included. Various verification tests are presented, including standard benchmark tests in one and two dimensions. SNIa models using the pure turbulent deflagration model and the delayed-detonation transition model are studied. The results are consistent with those in the literature. We compute the detailed chemical evolution using the tracer particles' histories, and we construct corresponding bolometric...
Development and Implementation of Radiation-Hydrodynamics Verification Test Problems
Marcath, Matthew J. [Los Alamos National Laboratory; Wang, Matthew Y. [Los Alamos National Laboratory; Ramsey, Scott D. [Los Alamos National Laboratory
2012-08-22T23:59:59.000Z
Analytic solutions to the radiation-hydrodynamic equations are useful for verifying any large-scale numerical simulation software that solves the same set of equations. The one-dimensional, spherically symmetric Coggeshall No.9 and No.11 analytic solutions, cell-averaged over a uniform-grid have been developed to analyze the corresponding solutions from the Los Alamos National Laboratory Eulerian Applications Project radiation-hydrodynamics code xRAGE. These Coggeshall solutions have been shown to be independent of heat conduction, providing a unique opportunity for comparison with xRAGE solutions with and without the heat conduction module. Solution convergence was analyzed based on radial step size. Since no shocks are involved in either problem and the solutions are smooth, second-order convergence was expected for both cases. The global L1 errors were used to estimate the convergence rates with and without the heat conduction module implemented.
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.
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.
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.
A hydrodynamic approach to boost invariant free streaming
Esteban Calzetta
2015-08-10T23:59:59.000Z
We consider a family of exact boost invariant solutions of the transport equation for free streaming massless particles, where the one particle distribution function is defi?ned in terms of a function of a single variable. The evolution of second and third moments of the one particle distribution function (the second moment being the energy momentum tensor (EMT) and the third moment the non equilibrium current (NEC)) depends only on two moments of that function. Given those two moments we show how to build a non linear hydrodynamic theory which reproduces the early time evolution of the EMT and the NEC. The structure of these theories may give insight on nonlinear hydrodynamic phenomena on short time scales.
A hydrodynamic approach to non-equilibrium conformal field theories
Denis Bernard; Benjamin Doyon
2015-07-27T23:59:59.000Z
We develop a hydrodynamic approach to non-equilibrium conformal field theory. We study non-equilibrium steady states in the context of one-dimensional conformal field theory perturbed by the $T\\bar T$ irrelevant operator. By direct quantum computation, we show, to first order in the coupling, that a relativistic hydrodynamic emerges, which is a simple modification of one-dimensional conformal fluids. We show that it describes the steady state and its approach, and we provide the main characteristics of the steady state, which lies between two shock waves. The velocities of these shocks are modified by the perturbation and equal the sound velocities of the asymptotic baths. Pushing further this approach, we are led to conjecture that the approach to the steady state is generically controlled by the power law $t^{-1/2}$, and that the widths of the shocks increase with time according to $t^{1/3}$.
A hydrodynamic approach to non-equilibrium conformal field theories
Bernard, Denis
2015-01-01T23:59:59.000Z
We develop a hydrodynamic approach to non-equilibrium conformal field theory. We study non-equilibrium steady states in the context of one-dimensional conformal field theory perturbed by the $T\\bar T$ irrelevant operator. By direct quantum computation, we show, to first order in the coupling, that a relativistic hydrodynamic emerges, which is a simple modification of one-dimensional conformal fluids. We show that it describes the steady state and its approach, and we provide the main characteristics of the steady state, which lies between two shock waves. The velocities of these shocks are modified by the perturbation and equal the sound velocities of the asymptotic baths. Pushing further this approach, we are led to conjecture that the approach to the steady state is generically controlled by the power law $t^{-1/2}$, and that the widths of the shocks increase with time according to $t^{1/3}$.
Hydrodynamics of an inelastic gas with implications for sonochemistry
James F. Lutsko
2005-10-09T23:59:59.000Z
The hydrodynamics for a gas of hard-spheres which sometimes experience inelastic collisions resulting in the loss of a fixed, velocity-independent, amount of energy $\\Delta $ is investigated with the goal of understanding the coupling between hydrodynamics and endothermic chemistry. The homogeneous cooling state of a uniform system and the modified Navier-Stokes equations are discussed and explicit expressions given for the pressure, cooling rates and all transport coefficients for D-dimensions. The Navier-Stokes equations are solved numerically for the case of a two-dimensional gas subject to a circular piston so as to illustrate the effects of the enegy loss on the structure of shocks found in cavitating bubbles. It is found that the maximal temperature achieved is a sensitive function of $\\Delta $ with a minimum occuring near the physically important value of $\\Delta \\sim 12,000K \\sim 1eV$
Soft Photons from transport and hydrodynamics at FAIR energies
Andreas Grimm; Bjørn Bäuchle
2012-11-11T23:59:59.000Z
Direct photon spectra from uranium-uranium collisions at FAIR energies (E(lab) = 35 AGeV) are calculated within the hadronic Ultra-relativistic Quantum Molecular Dynamics transport model. In this microscopic model, one can optionally include a macroscopic intermediate hydrodynamic phase. The hot and dense stage of the collision is then modeled by a hydrodynamical calculation. Photon emission from transport-hydro hybrid calculations is examined for purely hadronic matter and matter that has a cross-over phase transition and a critical end point to deconfined and chirally restored matter at high temperatures. We find the photon spectra in both scenarios to be dominated by Bremsstrahlung. Comparing flow of photons in both cases suggests a way to distinguish these two scenarios.
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.
Hydrodynamic equations for an electron gas in graphene
Luigi Barletti
2015-09-16T23:59:59.000Z
In this paper we review, and extend to the non-isothermal case, the results published in [L. Barletti, J. Math. Phys. 55, 083303 (2014)], concerning the application of the maximum entropy closure technique to the derivation of hydrodynamic equations for particles with spin-orbit interaction and Fermi-Dirac statistics. In the second part of the paper we treat in more details the case of electrons on a graphene sheet and investigate various asymptotic regimes
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.
THE KOZAI-LIDOV MECHANISM IN HYDRODYNAMICAL DISKS
Martin, Rebecca G.; Nixon, Chris; Armitage, Philip J. [JILA, University of Colorado and NIST, UCB 440, Boulder, CO 80309 (United States); Lubow, Stephen H. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Price, Daniel J. [Monash Centre for Astrophysics (MoCA), School of Mathematical Sciences, Monash University, Clayton, Vic. 3800 (Australia); Do?an, Suzan [Department of Astronomy and Space Sciences, University of Ege, Bornova, 35100 ?zmir (Turkey); King, Andrew [Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom)
2014-09-10T23:59:59.000Z
We use three-dimensional hydrodynamical simulations to show that a highly misaligned accretion disk around one component of a binary system can exhibit global Kozai-Lidov cycles, where the inclination and eccentricity of the disk are interchanged periodically. This has important implications for accreting systems on all scales, for example, the formation of planets and satellites in circumstellar and circumplanetary disks, outbursts in X-ray binary systems, and accretion onto supermassive black holes.
Constructing higher-order hydrodynamics: The third order
Sašo Grozdanov; Nikolaos Kaplis
2015-07-19T23:59:59.000Z
Hydrodynamics can be formulated as the gradient expansion of conserved currents in terms of the fundamental fields describing the near-equilibrium fluid flow. In the relativistic case, the Navier-Stokes equations follow from the conservation of the stress-energy tensor to first order in derivatives. In this paper, we go beyond the presently understood second-order hydrodynamics and discuss the systematisation of obtaining the hydrodynamic expansion to an arbitrarily high order. As an example of the algorithm that we present, we fully classify the gradient expansion at third order for neutral fluids in four dimensions, thus finding the most general next-to-leading-order corrections to the relativistic Navier-Stokes equations in curved space-time. In the process, we list $20$ new transport coefficients in the conformal and $68$ in the non-conformal case, without considering any constraints that could potentially arise from the entropy current analysis. We also obtain the third-order corrections to the linear dispersion relations that describe the propagation of diffusion and sound waves in relativistic fluids. We apply our results to the energy-momentum transport in the $\\mathcal{N}=4$ supersymmetric Yang-Mills fluid at infinite 't Hooft coupling and infinite number of colours, to find the values of two new conformal transport coefficients.
Constructing higher-order hydrodynamics: The third order
Grozdanov, Sašo
2015-01-01T23:59:59.000Z
Hydrodynamics can be formulated as the gradient expansion of conserved currents, in terms of the fundamental fields describing the near-equilibrium fluid flow. In the relativistic case, the Navier-Stokes equations follow from the conservation of the stress-energy tensor to first order in derivatives. In this paper, we go beyond the presently understood second-order hydrodynamics and discuss the systematisation of obtaining the hydrodynamic expansion to an arbitrarily high order. As an example, we fully classify the gradient expansion at third order for neutral fluids in four dimensions, thus finding the most general next-to-leading-order corrections to the relativistic Navier-Stokes equations. In the process, we list $20$ new transport coefficients in the conformal and $68$ in the non-conformal case. We also obtain the third-order corrections to the linear dispersion relations that describe the propagation of diffusion and sound waves in relativistic fluids. We apply our results to the energy-momentum transpo...
Hydrodynamically Lubricated Rotary Shaft Having Twist Resistant Geometry
Dietle, Lannie (Houston, TX); Gobeli, Jeffrey D. (Houston, TX)
1993-07-27T23:59:59.000Z
A hydrodynamically lubricated squeeze packing type rotary shaft with a cross-sectional geometry suitable for pressurized lubricant retention is provided which, in the preferred embodiment, incorporates a protuberant static sealing interface that, compared to prior art, dramatically improves the exclusionary action of the dynamic sealing interface in low pressure and unpressurized applications by achieving symmetrical deformation of the seal at the static and dynamic sealing interfaces. In abrasive environments, the improved exclusionary action results in a dramatic reduction of seal and shaft wear, compared to prior art, and provides a significant increase in seal life. The invention also increases seal life by making higher levels of initial compression possible, compared to prior art, without compromising hydrodynamic lubrication; this added compression makes the seal more tolerant of compression set, abrasive wear, mechanical misalignment, dynamic runout, and manufacturing tolerances, and also makes hydrodynamic seals with smaller cross-sections more practical. In alternate embodiments, the benefits enumerated above are achieved by cooperative configurations of the seal and the gland which achieve symmetrical deformation of the seal at the static and dynamic sealing interfaces. The seal may also be configured such that predetermined radial compression deforms it to a desired operative configuration, even through symmetrical deformation is lacking.
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.
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.
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.
EINDHOVEN UNIVERSITY OF TECHNOLOGY Department of Mathematics and Computer Science
Eindhoven, Technische Universiteit
, Slovenia 4Newcastle University, United Kingdom 5Deltares, Delft, The Netherlands 6Budapest University is rather complex. The flow behaviour is measured by various instruments and hence a thorough hydrodynamic hydraulic applications, such as water-distribution networks, storm-water and sewage systems, fire
The evolution of asteroids in the jumping-Jupiter migration model
Roig, Fernando
2015-01-01T23:59:59.000Z
In this work, we investigate the evolution of a primordial belt of asteroids, represented by a large number of massless test particles, under the gravitational effect of migrating Jovian planets in the framework of the jumping-Jupiter model. We perform several simulations considering test particles distributed in the Main Belt, as well as in the Hilda and Trojan groups. The simulations start with Jupiter and Saturn locked in the mutual 3:2 mean motion resonance plus 3 Neptune-mass planets in a compact orbital configuration. Mutual planetary interactions during migration led one of the Neptunes to be ejected in less than 10 Myr of evolution, causing Jupiter to jump by about 0.3 au in semi-major axis. This introduces a large scale instability in the studied populations of small bodies. After the migration phase, the simulations are extended over 4 Gyr, and we compare the final orbital structure of the simulated test particles to the current Main Belt of asteroids with absolute magnitude $H<9.7$. The results ...
Arizona State University | Open Energy Information
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University of Alberta | Open Energy Information
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University of Greenwich | Open Energy Information
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University of Lisbon | Open Energy Information
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University of Johannesburg | Open Energy Information
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University of Minnesota | Open Energy Information
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University, Florida: Energy Resources | Open Energy Information
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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.
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
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
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.
Property:Hydrodynamic Testing Facility Type | Open Energy Information
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Assessing Thermo-Hydrodynamic-Chemical Processes at the Dixie Valley
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 on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaP a gHigh4-FD-a <AlaskaApplied EnergyAshton, Illinois: Energy ResourcesSolar JumpGeothermal Area- A
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.
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.
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.
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 effects on coalescence. (Technical Report) | SciTech Connect
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On freeze-out problem in relativistic hydrodynamics
Ivanov, Yu. B., E-mail: Y.Ivanov@gsi.de; Russkikh, V. N. [Gesellschaft fuer Schwerionenforschung mbH (Germany)
2009-07-15T23:59:59.000Z
A finite unbound system which is equilibrium in one reference frame is in general nonequilibrium in another frame. This is a consequence of the relative character of the time synchronization in the relativistic physics. This puzzle was a prime motivation of the Cooper-Frye approach to the freeze-out in relativistic hydrodynamics. Solution of the puzzle reveals that the Cooper-Frye recipe is far not a unique phenomenological method that meets requirements of energy-momentum conservation. Alternative freeze-out recipes are considered and discussed.
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.
Mohaghegh, Shahab
P UNIVERSITY AVE UNIVERSITY AVE UNIVERSITY AVE UNIVERSITY AVE PATTESON DR VANVOORHISRDVANVOORHISR STKREPPS AVE BROAD ST ELM ST DOGWOOD ST UNIVERSITY AVE MONONGAHELABLVD US HWY 19 41 48 Patient 48 53 78 58 Complex Pierpont Apartments UNIVERSITY PARK Erickson Alumni Center Fieldcrest Hall University Services
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.
Limiting results for the free energy of directed polymers in random environment with unbounded jumps
Francis Comets; Ryoki Fukushima; Shuta Nakajima; Nobuo Yoshida
2015-08-11T23:59:59.000Z
We study asymptotics 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 Bernoulli variables. We first establish the existence and continuity of the free energy 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.
Anomalous specific heat jump in a two-component ultracold Fermi gas
Armen Sedrakian; Herbert Müther; Artur Polls
2006-09-20T23:59:59.000Z
The thermodynamic functions of a Fermi gas with spin population imbalance are studied in the temperature-asymmetry plane in the BCS limit. The low temperature domain is characterized by anomalous enhancement of the entropy and the specific heat above their values in the unpaired state, decrease of the gap and eventual unpairing phase transition as the temperature is lowered. The unpairing phase transition induces a second jump in the specific heat, which can be measured in calorimetric experiments. While the superfluid is unstable against a supercurrent carrying state, it may sustain a metastable state if cooled adiabatically down from the stable high-temperature domain. In the latter domain the temperature dependence of the gap and related functions is analogous to the predictions of the BCS theory.
Refining a relativistic, hydrodynamic solver: Admitting ultra-relativistic flows
J. P. Bernstein; P. A. Hughes
2009-07-23T23:59:59.000Z
We have undertaken the simulation of hydrodynamic flows with bulk Lorentz factors in the range 10^2--10^6. We discuss the application of an existing relativistic, hydrodynamic primitive-variable recovery algorithm to a study of pulsar winds, and, in particular, the refinement made to admit such ultra-relativistic flows. We show that an iterative quartic root finder breaks down for Lorentz factors above 10^2 and employ an analytic root finder as a solution. We find that the former, which is known to be robust for Lorentz factors up to at least 50, offers a 24% speed advantage. We demonstrate the existence of a simple diagnostic allowing for a hybrid primitives recovery algorithm that includes an automatic, real-time toggle between the iterative and analytical methods. We further determine the accuracy of the iterative and hybrid algorithms for a comprehensive selection of input parameters and demonstrate the latter's capability to elucidate the internal structure of ultra-relativistic plasmas. In particular, we discuss simulations showing that the interaction of a light, ultra-relativistic pulsar wind with a slow, dense ambient medium can give rise to asymmetry reminiscent of the Guitar nebula leading to the formation of a relativistic backflow harboring a series of internal shockwaves. The shockwaves provide thermalized energy that is available for the continued inflation of the PWN bubble. In turn, the bubble enhances the asymmetry, thereby providing positive feedback to the backflow.
Multi-Thread Hydrodynamic Modeling of a Solar Flare
Harry P. Warren
2005-07-13T23:59:59.000Z
Past hydrodynamic simulations have been able to reproduce the high temperatures and densities characteristic of solar flares. These simulations, however, have not been able to account for the slow decay of the observed flare emission or the absence of blueshifts in high spectral resolution line profiles. Recent work has suggested that modeling a flare as an sequence of independently heated threads instead of as a single loop may resolve the discrepancies between the simulations and observations. In this paper we present a method for computing multi-thread, time-dependent hydrodynamic simulations of solar flares and apply it to observations of the Masuda flare of 1992 January 13. We show that it is possible to reproduce the temporal evolution of high temperature thermal flare plasma observed with the instruments on the \\textit{GOES} and \\textit{Yohkoh} satellites. The results from these simulations suggest that the heating time-scale for a individual thread is on the order of 200 s. Significantly shorter heating time scales (20 s) lead to very high temperatures and are inconsistent with the emission observed by \\textit{Yohkoh}.
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 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.
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.
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.
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.
Modelling the Mechanics and Hydrodynamics of Swimming E. coli
Jinglei Hu; Mingcheng Yang; Gerhard Gompper; Roland G. Winkler
2015-08-04T23:59:59.000Z
The swimming properties of an E. coli-type model bacterium are investigated by mesoscale hy- drodynamic simulations, combining molecular dynamics simulations of the bacterium with the multiparticle particle collision dynamics method for the embedding fluid. The bacterium is com- posed of a spherocylindrical body with attached helical flagella, built up from discrete particles for an efficient coupling with the fluid. We measure the hydrodynamic friction coefficients of the bacterium and find quantitative agreement with experimental results of swimming E. coli. The flow field of the bacterium shows a force-dipole-like pattern in the swimming plane and two vor- tices perpendicular to its swimming direction arising from counterrotation of the cell body and the flagella. By comparison with the flow field of a force dipole and rotlet dipole, we extract the force- dipole and rotlet-dipole strengths for the bacterium and find that counterrotation of the cell body and the flagella is essential for describing the near-field hydrodynamics of the bacterium.
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.
Bulk Viscosity and Cavitation in Boost-Invariant Hydrodynamic Expansion
Rajagopal, Krishna
2009-01-01T23:59:59.000Z
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 th...
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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
Cross, J. E.; Gregori, G. [Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom); Reville, B., E-mail: j.e.cross@physics.ox.ac.uk [Centre for Plasma Physics, Queen's University Belfast, University Road, Belfast BT7 1NN (United Kingdom)
2014-11-01T23:59:59.000Z
We introduce the equations of magneto-quantum-radiative hydrodynamics. By rewriting them in a dimensionless form, we obtain a set of parameters that describe scale-dependent ratios of characteristic hydrodynamic quantities. We discuss how these dimensionless parameters relate to the scaling between astrophysical observations and laboratory experiments.
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
Alvaro Domínguez
2014-10-10T23:59:59.000Z
It has been shown recently that the coefficient of collective diffusion in a colloidal monolayer is divergent due to the hydrodynamic interactions mediated by the ambient fluid in bulk. The analysis is extended to allow for time--dependent hydrodynamic interactions. Novel observational features specific to this time dependency are predicted. The possible experimental detection in the dynamics of the monolayer is discussed.
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
Shashkov, Mikhail
A Pressure Relaxation Closure Model for One-Dimensional, Two-Material Lagrangian Hydrodynamics Laboratory, Los Alamos, NM USA Abstract. Despite decades of development, Lagrangian hydrodynamics of strength of assigning sub-cell pressures to the physics associ- ated with the local, dynamic evolution. We package our
Hydrodynamic modeling of tsunamis from the Currituck landslide Eric L. Geist a,
Lynett, Patrick
Hydrodynamic modeling of tsunamis from the Currituck landslide Eric L. Geist a, , Patrick J. Lynett: Accepted 24 September 2008 Keywords: tsunami landslide hydrodynamic runup numerical model sensitivity analysis Tsunami generation from the Currituck landslide offshore North Carolina and propagation of waves
Hydrodynamic oscillations and tunable swimming speed in squirmers close to repulsive walls
Lintuvuori, Juho S; Stratford, Kevin; Marenduzzo, Davide
2015-01-01T23:59:59.000Z
We present a lattice Boltzmann study of the hydrodynamics of a fully resolved squirmer, radius R, confined in a slab of fluid between two no-slip walls. We show that the coupling between hydrodynamics and short-range repulsive interactions between the swimmer and the surface can lead to hydrodynamic trapping of both pushers and pullers at the wall, and to hydrodynamic oscillations in the case of a pusher. We further show that a pusher moves significantly faster when close to a surface than in the bulk, whereas a puller undergoes a transition between fast motion and a dynamical standstill according to the range of the repulsive interaction. Our results critically require near-field hydrodynamics; they further suggest that it should be possible to control density and speed of squirmers at a surface by tuning the range of steric and electrostatic swimmer-wall interactions.
. Environmental engineering, mixing and transport, water quality, ocean thermal energy conversion, hydrogen. GENO engineering, hydrodynamics, computational methods, water wave mechanics, sediment transport. R. CENGIZ ERTEKIN Professor, PhD 1984, UC Berkeley. Hydrodynamics/elasticity, computational methods, nonlinear water waves
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
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.
Anisotropic flow in transport+hydrodynamics hybrid approaches
Hannah Petersen
2014-11-26T23:59:59.000Z
This contribution to the focus issue covers anisotropic flow in hybrid approaches. The historical development of hybrid approaches and their impact on the interpretation of flow measurements is reviewed. The major ingredients of a hybrid approach and the transition criteria between transport and hydrodynamics are discussed. The results for anisotropic flow in (event-by-event) hybrid approaches are presented. Some hybrid approaches rely on hadronic transport for the late stages for the reaction (so called afterburner) and others employ transport approaches for the early non equilibrium evolution. In addition, there are 'full' hybrid calculations where a fluid evolution is dynamically embedded in a transport simulation. After demonstrating the success of hybrid approaches at high RHIC and LHC energies, existing hybrid caluclations for collective flow observables at lower beam energies are discussed and remaining challenges outlined.
Hydrodynamic analysis of laser-driven cylindrical implosions
Ramis, R. [E.T.S.I. Aeronáuticos, Universidad Politécnica de Madrid (Spain)] [E.T.S.I. Aeronáuticos, Universidad Politécnica de Madrid (Spain)
2013-08-15T23:59:59.000Z
Three-dimensional hydrodynamic simulations are performed to study laser-driven cylindrical implosions in the context of experiments (F. Perez et al., Plasma Phys. Controlled Fusion 51, 124035 (2009)) carried out at the Rutherford Appleton Laboratory in the framework of the HiPER project. The analysis is carried out by using the 3D version of the hydrocode MULTI (R. Ramis et al., Comput. Phys. Commun. 49, 475-505 (1988)). The influence of the main laser parameters on implosion performance and symmetry is consistently studied and compared with the results of 2D analysis. Furthermore, the effects of uncertainties in laser irradiation (pointing, focusing, power balance, and time jitter) on implosion performance (average peak density and temperature) are studied by means of statistical analysis.
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.
An Eulerian PPM & PIC Code for Cosmological Hydrodynamics
A. Sornborger; B. Fryxell; K. Olson; P. MacNeice
1996-08-05T23:59:59.000Z
We present a method for integrating the cosmological hydrodynamical equations including a collisionless dark matter component. For modelling the baryonic matter component, we use the Piecewise Parabolic Method (PPM) which is a high-accuracy shock capturing technique. The dark matter component is modeled using gravitationally interacting particles whose evolution is determined using standard particle-in-cell techniques. We discuss details of the inclusion of gravity and expansion in the PPM code and give results of a number of tests of the code. This code has been developed for a massively parallel, SIMD supercomputer: the MasPar MP-2 parallel processor. We present details of the techniques we have used to implement the code for this architecture and discuss performance of the code on the MP-2. The code processes $5.0 \\times 10^4$ grid zones per second and requires 53 seconds of machine time for a single timestep in a $128^3$ simulation.
Hydrodynamics of the physical vacuum: dark matter is an illusion
Valeriy I. Sbitnev
2015-06-23T23:59:59.000Z
The relativistic hydrodynamical equations are being examined with the aim of extracting the quantum-mechanical equations (the relativistic Klein-Gordon equation and the Schr\\"odinger equation in the non-relativistic limit). In both cases it is required to get the quantum potential, which follows from pressure gradients within a superfluid vacuum medium. This special fluid, endowed with viscosity allows to describe emergence of the flat orbital speeds of spiral galaxies. The viscosity averaged on time vanishes, but its variance is different from zero. It is a function fluctuating about zero. Therefore the flattening is the result of the energy exchange of the torque with zero-point fluctuations of the physical vacuum on the ultra-low frequencies.
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.
Hydrodynamics of the physical vacuum: dark matter is an illusion
Sbitnev, Valeriy I
2015-01-01T23:59:59.000Z
The relativistic hydrodynamical equations are being examined with the aim of extracting the quantum-mechanical equations (the relativistic Klein-Gordon equation and the Schr\\"odinger equation in the non-relativistic limit). In both cases it is required to get the quantum potential, which follows from pressure gradients within a superfluid vacuum medium. This special fluid, endowed with viscosity allows to describe emergence of the flat orbital speeds of spiral galaxies. The viscosity averaged on time vanishes, but its variance is different from zero. It is a function fluctuating about zero. Therefore the flattening is the result of the energy exchange of the torque with zero-point fluctuations of the physical vacuum on the ultra-low frequencies.
Flow harmonics within an analytically solvable viscous hydrodynamic model
Yoshitaka Hatta; Jorge Noronha; Giorgio Torrieri; Bo-Wen Xiao
2014-10-01T23:59:59.000Z
Based on a viscous hydrodynamic model with anisotropically perturbed Gubser flow and isothermal Cooper-Frye freezeout at early times, we analytically compute the flow harmonics $v_n(p_T)$ and study how they scale with the harmonic number $n$ and transverse momentum, as well as the system size, shear and bulk viscosity coefficients, and collision energy. In particular, we find that the magnitude of shear viscous corrections grows linearly with $n$. The mixing between different harmonics is also discussed. While this model is rather simple as compared to realistic heavy-ion collisions, we argue that the scaling results presented here may be meaningfully compared to experimental data collected over many energies, system sizes, and geometries.
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.
Simulated VLBI Images From Relativistic Hydrodynamic Jet Models
Amy J. Mioduszewski; Philip A. Hughes; G. Comer Duncan
1996-06-03T23:59:59.000Z
A series of simulated maps showing the appearance in total intensity of flows computed using a recently developed relativistic hydrodynamic code (Duncan \\& Hughes 1994: ApJ, 436, L119) are presented. The radiation transfer calculations were performed by assuming the flow is permeated by a magnetic field and fast particle distribution in energy equipartition, with energy density proportional to the hydrodynamic energy density (i.e., pressure). We find that relativistic flows subject to strong perturbations exhibit a density structure consisting of a series of nested bow shocks, and that this structure is evident in the intensity maps for large viewing angles. However, for viewing angles $<30^{\\circ}$, differential Doppler boosting leads to a series of axial knots of emission, similar to the pattern exhibited by many VLBI sources. The appearance of VLBI knots is determined primarily by the Doppler boosting of parts of a more extended flow. To study the evolution of a perturbed jet, a time series of maps was produced and an integrated flux light curve created. The light curve shows features characteristic of a radio loud AGN: small amplitude variations and a large outburst. We find that in the absence of perturbations, jets with a modest Lorentz factor ($\\sim 5$) exhibit complex intensity maps, while faster jets (Lorentz factor $\\sim 10$) are largely featureless. We also study the appearance of kiloparsec jet-counterjet pairs by producing simulated maps at relatively large viewing angles; we conclude that observed hot spot emission is more likely to be associated with the Mach disk than with the outer, bow shock.
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.
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.
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.
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.
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.
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.
University of Iowa | Open Energy Information
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University of Kansas | Open Energy Information
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University of Maine | 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 on Google Bookmark EERE: Alternative Fuels Data Center Home Page onsource History View NewUS National Fuel Cell Research Center NFCRC JumpUniversal LightingUniversity ofUniversity ofform
60yearsofFluidMechanicsSeminarsatStanford From Jumping Drops to Thermal Diodes
Prinz, Friedrich B.
Drilling Muds Dr. Sourav Padhy Feb. 26 Dept. of Mechanical Engineering, Stanford University Oil and Gas Releases in Deepwater: Processes, Behavior and Modeling Prof. Poojitha Yapa Mar. 5 Dept. of Civil
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.
Rajarshi Chakrabarti
2011-05-04T23:59:59.000Z
Based on the Wilemski-Fixman approach (J. Chem. Phys. 60, 866 (1974)) we showed that for a flexible chain in theta solvent hydrodynamic interaction treated with an pre-averaging approximation makes ring closing faster if the chain is not very short. Only for a very short chain the ring closing is slower with hydrodynamic interaction on. We have also shown that the ring closing time for a chain with hydrodynamic interaction in theta solvent scales with the chain length (N) as N^(1.527), in good agreement with previous renormalization group calculation based prediction by Freidman et al. (Phys. Rev. A. 40, 5950 (1989)).
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.
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.
University of California Davis | Open Energy Information
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University of california | Open Energy Information
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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.
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.
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.
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.
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 .
Thermal and hydrodynamic effects in the ordering of lamellar fluids
G. Gonnella; A. Lamura; A. Tiribocchi
2011-02-15T23:59:59.000Z
Phase separation in a complex fluid with lamellar order has been studied in the case of cold thermal fronts propagating diffusively from external walls. The velocity hydrodynamic modes are taken into account by coupling the convection-diffusion equation for the order parameter to a generalised Navier-Stokes equation. The dynamical equations are simulated by implementing a hybrid method based on a lattice Boltzmann algorithm coupled to finite difference schemes. Simulations show that the ordering process occurs with morphologies depending on the speed of the thermal fronts or, equivalently, on the value of the thermal conductivity {\\xi}. At large value of {\\xi}, as in instantaneous quenching, the system is frozen in entangled configurations at high viscosity while consists of grains with well ordered lamellae at low viscosity. By decreasing the value of {\\xi}, a regime with very ordered lamellae parallel to the thermal fronts is found. At very low values of {\\xi} the preferred orientation is perpendicular to the walls in d = 2, while perpendicular order is lost moving far from the walls in d = 3.
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.
Entropy production in non-equilibrium fluctuating hydrodynamics
Giacomo Gradenigo; Andrea Puglisi; Alessandro Sarracino
2012-05-16T23:59:59.000Z
Fluctuating entropy production is studied for a set of linearly coupled complex fields. The general result is applied to non-equilibrium fluctuating hydrodynamic equations for coarse-grained fields (density, temperature and velocity), in the framework of model granular fluids. We find that the average entropy production, obtained from the microscopic stochastic description, can be expressed in terms of macroscopic quantities, in analogy with linear non-equilibrium thermodynamics. We consider the specific cases of driven granular fluids with two different kinds of thermostat and the homogeneous cooling regime. In all cases, the average entropy production turns out to be the product of a thermodynamic force and a current: the former depends on the specific energy injection mechanism, the latter takes always the form of a static correlation between fluctuations of density and temperature time-derivative. Both vanish in the elastic limit. The behavior of the entropy production is studied at different length scales and the qualitative differences arising for the different granular models are discussed.
Purely hydrodynamic ordering of rotating disks at a finite Reynolds number
Goto, Yusuke
2015-01-01T23:59:59.000Z
Self-organization of moving objects in hydrodynamic environments has recently attracted considerable attention in connection to natural phenomena and living systems. However, the underlying physical mechanism is much less clear due to the intrinsically nonequilibrium nature, compared with self-organization of thermal systems. Hydrodynamic interactions are believed to play a crucial role in such phenomena. To elucidate the fundamental physical nature of many-body hydrodynamic interactions at a finite Reynolds number, here we study a system of co-rotating hard disks in a two-dimensional viscous fluid at zero temperature. Despite the absence of thermal noise, this system exhibits rich phase behaviours, including a fluid state with diffusive dynamics, a cluster state, a hexatic state, a glassy state, a plastic crystal state and phase demixing.We reveal that these behaviours are induced by the off-axis and many-body nature of nonlinear hydrodynamic interactions and the finite time required for propagating the inte...
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
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 ...
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...
Venkataraman, Balaji
1995-01-01T23:59:59.000Z
of these pumps depend significantly on the rotordynamic features of hardware elements such as the seals and bearings. The focus of this research effort is to develop a comprehensive thermo-elasto-hydrodynamic analysis of turbulent liquid annular seals...
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
Pandoe, Wahyu Widodo
2004-09-30T23:59:59.000Z
provides a basis for determining how the water circulation three-dimensionally controls the hydrodynamics of the system and ultimately transports the suspended and soluble materials due to combined currents and waves. A three-dimensional circulation model...
Using Genetic Algorithms to Optimize Bathymetric Surveys for Hydrodynamic Model Input
Manian, Dinesh
2010-07-14T23:59:59.000Z
The first part of this thesis deals with studying the effect of the specified bathymetric resolution and ideal bathymetric form parameters on the output from the wave and hydrodynamic modules of Delft-3D. This thesis then describes the use...
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.
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
Hydrodynamically-driven colloidal assembly in the thin-film entrainment regime
Carlos E. Colosqui; Jeffrey F. Morris; Howard A. Stone
2012-10-01T23:59:59.000Z
We study numerically the hydrodynamics of dip coating from a suspension and report a mechanism for colloidal assembly and pattern formation on smooth and uniform substrates. Below a critical withdrawal speed of the substrate, capillary forces required to deform the meniscus prevent colloidal particles from entering the coating film. Capillary forces are overcome by hydrodynamic drag only after a minimum number of particles organize in a close-packed formation within the meniscus. Once within the film, the formed assembly moves at nearly the withdrawal speed and rapidly separates from the next assembly. The interplay between hydrodynamic and capillary forces can thus produce periodic and regular structures within the curved meniscus that extends below the withdrawn film. The hydrodynamically-driven assembly documented here is consistent with stripe pattern formations observed experimentally in the so-called thin-film entrainment regime.
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 ...
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 ...
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 ...
Lu, Chang
Characterizing osmotic lysis kinetics under microfluidic hydrodynamic focusing for erythrocyte microfluidic tool for examining erythrocyte fragility based on characterizing osmotic lysis kinetics deformability include osmotic fragility tests,1820 filtration,21,22 ektacytometry,2325 rheoscopy,26
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 ...
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...
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...
MHK Projects/Marine Hydrodynamics Laboratory at the University of Michigan
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Federal University of Sao Carlos | Open Energy Information
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Universal Energy | Open Energy Information
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Bucknell University | Open Energy Information
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A cloud model interpretation of jumping cirrus above storm top Pao K. Wang
Wang, Pao K.
Atmospheric Composition and Structure: Middle atmosphere--constituent transport and chemistry (3334); 0320 Atmospheric Composition and Structure: Cloud physics and chemistry; 3314 Meteorology and Atmospheric Dynamics of Atmospheric and Oceanographic Sciences, University of Wisconsin-Madison, Madison, Wisconsin, USA Received 18
Self-cleaning of superhydrophobic surfaces by self-propelled jumping condensate
Chen, Chuan-Hua
-Hua Chena,2 a Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC 27708 the superhydrophobic surface is powered by the sur- face energy released upon coalescence of the condensed water phase, or wind flow. Our findings offer insights for the development of self-cleaning materials. particle
University Park, Maryland: Energy Resources | Open Energy Information
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University Park, Texas: Energy Resources | Open Energy Information
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University of Illinois Chicago UIC | Open Energy Information
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Uppsala University Division for Electricity | Open Energy Information
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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.
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.
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.
University of Colorado | Open Energy Information
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University of Delaware | Open Energy Information
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University of Manchester | Open Energy Information
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University of Maryland | 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 on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaP a gHigh4-FD-a < RAPIDâ€Ž |SpaceThe GermanUSFSUnalakleet JumpUnitedUniversityUniversity
University of Pittsburgh | 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 on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaP a gHigh4-FD-a < RAPIDâ€Ž |SpaceThe GermanUSFSUnalakleetUniversity of Neuchatel Jump to:University
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.
Antsaklis, Panos
Control Problems with State Jumps," Proceedings of the 15th International Symposium on Mathematical Theory Control Problems with State Jumps," Proceedings of the 15th International Symposium on Mathematical Theory Control Problems with State Jumps," Proceedings of the 15th International Symposium on Mathematical Theory
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...
Web-Based Hydrodynamics Computing Alan Shimoide1
Yoon, Ilmi
University Abstract Proteins are long chains of amino acids that have a definite 3-d conformation through a web browser. 1. Introduction Proteins are long chains of amino acids that have a definite conformation in three dimensions after the chain of amino acids has been folded in a specific fashion. Proteins
University Library University of Saskatchewan
Saskatchewan, University of
University Library University of Saskatchewan Core Competencies for University of Saskatchewan Librarians This document defines the basic knowledge and skills librarians at the University of Saskatchewan in the Canadian academic research environment. The University Library Competencies Framework (Figure 1) maps
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.
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.
Hydrodynamics of phase transition fronts and the speed of sound in the plasma
Leonardo Leitao; Ariel Megevand
2015-03-06T23:59:59.000Z
The growth of bubbles in cosmological first-order phase transitions involves nontrivial hydrodynamics. For that reason, the study of the propagation of phase transition fronts often requires several approximations. A frequently used approximation consists in describing the two phases as being composed only of radiation and vacuum energy (the so-called bag equation of state). We show that, in realistic models, the speed of sound in the low-temperature phase is generally smaller than that of radiation, and we study the hydrodynamics in such a situation. We find in particular that a new kind of hydrodynamical solution may be possible, which does not arise in the bag model. We obtain analytic results for the efficiency of the transfer of latent heat to bulk motions of the plasma, as a function of the speed of sound in each phase.
Pawlik, Andreas H; Vecchia, Claudio Dalla
2015-01-01T23:59:59.000Z
We present a suite of cosmological radiation-hydrodynamical simulations of the assembly of galaxies driving the reionization of the intergalactic medium (IGM) at z >~ 6. The simulations account for the hydrodynamical feedback from photoionization heating and the explosion of massive stars as supernovae (SNe). Our reference simulation, which was carried out in a box of size 25 comoving Mpc/h using 2 x 512^3 particles, produces a reasonable reionization history and matches the observed UV luminosity function of galaxies. Simulations with different box sizes and resolutions are used to investigate numerical convergence, and simulations in which either SNe or photoionization heating or both are turned off, are used to investigate the role of feedback from star formation. Ionizing radiation is treated using accurate radiative transfer at the high spatially adaptive resolution at which the hydrodynamics is carried out. SN feedback strongly reduces the star formation rates (SFRs) over nearly the full mass range of s...
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.
Hydrodynamic flow in lower Cretaceous Muddy sandstone, Gas Draw Field, Powder River Basin, Wyoming
Lin, Joseph Tien-Chin
1978-01-01T23:59:59.000Z
potentiometric gradient of 32 ft/mi across the field yields a hydrodynamic oil column of 210 ft, whereas capillary-pressure differ- ences due to permeability changes can account for only 38 ft of oil column. The observed oil column over most of the field has a... height somewhat greater than 250 ft. The agreement between total calculated oil column of about 248 ft and the observed oil column demonstrates that the positive hydrodynamic gradient across the reservoir and the decrease in permeability updip...
Transport Coefficients of Non-Newtonian Fluid and Causal Dissipative Hydrodynamics
T. Koide; T. Kodama
2008-10-20T23:59:59.000Z
A new formula to calculate the transport coefficients of the causal dissipative hydrodynamics is derived by using the projection operator method (Mori-Zwanzig formalism) in [T. Koide, Phys. Rev. E75, 060103(R) (2007)]. This is an extension of the Green-Kubo-Nakano (GKN) formula to the case of non-Newtonian fluids, which is the essential factor to preserve the relativistic causality in relativistic dissipative hydrodynamics. This formula is the generalization of the GKN formula in the sense that it can reproduce the GKN formula in a certain limit. In this work, we extend the previous work so as to apply to more general situations.
Exploring Hydrodynamic Modeling of Texas Bays With focus on Corpus Christi Bay & Lavaca Bay
Furnans, Jordan
2004-01-01T23:59:59.000Z
on the circulation and salinity patterns within the estuarine system. The model of choice is the 2- dimensional, depth averaged finite element model TxBLEND. Exploring Hydrodynamic Modeling of Texas Bays - Furnans 4 Figure 4 – TxBLEND Finite Element Grid w... of the isnull grid function in ArcGIS. Once this second grid is completed, the final bathymetry grid is created by adding the grids from step one and step two. Exploring Hydrodynamic Modeling of Texas Bays - Furnans 14 Figure 10 – Continuous...
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...
University of Minnesota -- Morris Wind Farm | Open Energy Information
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University of Minnesota Morris II - PES | Open Energy Information
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University of Illinois at Urbana Champaign | 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 on Google Bookmark EERE: Alternative Fuels Data Center Home Page onsource History View NewUS National Fuel Cell Research Center NFCRC JumpUniversal LightingUniversity of CapeUniversity of
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.
Influence of increased gas density on hydrodynamics of bubble-column reactors
Krishna, R.; Swart, J.W.A. de; Hennephof, D.E.; Ellenberger, J.; Hoefsloot, H.C.J. (Univ. of Amsterdam (Netherlands). Dept. of Chemical Engineering)
1994-01-01T23:59:59.000Z
A mechanistic background to the understanding of the hydrodynamics of high-pressure bubble column reactors in both the homogeneous and heterogeneous flow regimes is discussed. An important parameter determining the stability of homogeneous bubbly flow in a bubble column is shown to be the Richardson-Zaki exponent in the bubble swarm velocity relationship V[sub swarm] = [upsilon][sub [infinity
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
The Segmented Height Field and Smoothed Particle Hydrodynamics in Erosion Simulation
Franklin, W. Randolph
Katrina and has been replaced with a cement retaining wall. #12;Terms Erosion - refers to hydraulic erosion, or the physical wearing away or breaking down of a material by running water Earthen dams - walls., Hydraulic Erosion Using Smoothed Particle Hydrodynamics, 2009. #12;Why Use SPH? Not hindered by grid
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
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
Kinetic equation for a soliton gas, its hydrodynamic reductions and symmetries
Kinetic equation for a soliton gas, its hydrodynamic reductions and symmetries G.A. El1 , A 2 Institute of Spectroscopy, Russian Academy of Sciences, Troitsk, Moscow Region, Russia 3 Lebedev Physics, Urals Division of Russian Academy of Sciences, Ekaterinburg, Russia Abstract We study a new class
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
Basic design and hydrodynamic analysis of three-column TLP and comparison with ISSC TLP
Sebastian, Abhilash
2000-01-01T23:59:59.000Z
Three-column TLP is a new design variation of the common four-column TLP. The objective of this study is to find the hydrodynamic feasibility of the three-column TLP. This accomplished by comparing the three-column design to the ISSC TLP. The ISSC...
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
Coiling, Entrainment, and Hydrodynamic Coupling of Decelerated Fluid Jets Christopher Dombrowski,1
Goldstein, Raymond E.
Coiling, Entrainment, and Hydrodynamic Coupling of Decelerated Fluid Jets Christopher Dombrowski,1 a corkscrew within a conduit of viscously entrained fluid, whose upward recirculation braids the jet issues in all are mixing and entrainment by the jet and the nonlinear regime far beyond the instabilities
A hydrodynamic theory for solutions of nonhomogeneous nematic liquid crystalline polymers of
A hydrodynamic theory for solutions of nonhomogeneous nematic liquid crystalline polymers of di#11 polymers (LCPs) of a variety of molecular con#12;gurations in proximity of spheroids, extending the Doi to be applicable to high molar weight liquid crystalline polymers. Although the LE theory was #12;rst developed
1. Department, course number, title ORE 609 Hydrodynamics of Fluid-Body Interaction
on Offshore Structures 2. Newman: Marine Hydrodynamics 3. Currie: Fundamental Mechanics of Fluids 4. Ippen and Stegun: Handbook of Mathematical Functions 7. Gradshteyn and Ryzhik: Table of Integrals, Series Component Engineering science: 2 credits Engineering design: 1 credit 10. Relationship of the Course
Hydrodynamical simulations of penetrative convection and generation of internal gravity waves
StÃªpieÃ±, Kazimierz
of hydrodynamical simulations. We measure the energy flux transported by these waves and find it compatibleÂLopez & Spruit 1991), mixing by random motions induced by the waves (Schatzman 1996), and the transport depends on the efficiency of the generation of internal gravity waves, which is linked to the dynamics
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
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
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
McArthur, Karl Edward
1996-01-01T23:59:59.000Z
, and hydraulic structures. The results of the SW=D model were compared to results from an application of the TXBLEND model by Texas Water Development Board to the same part of the estuary. TXBLEND is a two-dimensional hydrodynamic model based on the finite...
A Phase Field Crystal Model for Colloidal Suspensions with Hydrodynamic Interactions
Praetorius, Simon
2013-01-01T23:59:59.000Z
We develop a fully continuous model for colloidal suspensions with hydrodynamic interactions. The Navier Stokes Phase Field Crystal (NS-PFC) model combines ideas of dynamic density functional theory with particulate flow approaches. The proposed dynamical equations are shown to be energy stable. The system is numerically solved using adaptive finite elements. The resulting approach is validated against computational and experimental studies for sedimentation.
Purely hydrodynamic ordering of rotating disks at a finite Reynolds number
Yusuke Goto; Hajime Tanaka
2015-02-18T23:59:59.000Z
Self-organization of moving objects in hydrodynamic environments has recently attracted considerable attention in connection to natural phenomena and living systems. However, the underlying physical mechanism is much less clear due to the intrinsically nonequilibrium nature, compared with self-organization of thermal systems. Hydrodynamic interactions are believed to play a crucial role in such phenomena. To elucidate the fundamental physical nature of many-body hydrodynamic interactions at a finite Reynolds number, here we study a system of co-rotating hard disks in a two-dimensional viscous fluid at zero temperature. Despite the absence of thermal noise, this system exhibits rich phase behaviours, including a fluid state with diffusive dynamics, a cluster state, a hexatic state, a glassy state, a plastic crystal state and phase demixing.We reveal that these behaviours are induced by the off-axis and many-body nature of nonlinear hydrodynamic interactions and the finite time required for propagating the interactions by momentum diffusion.
Characterizing the Hydrodynamics of Bubbling Fluidized Beds with Multivariate Pressure Measurements
Tennessee, University of
Characterizing the Hydrodynamics of Bubbling Fluidized Beds with Multivariate Pressure Measurements mounted on the walls of a bubbling fluidized bed. Our objective was to identify multivariate dynamic of bubbling fluidized beds with multivariate pressure measurements. 2000 AIChE Annual Meeting (Los Angeles
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
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
Video Article A Microfluidic-based Hydrodynamic Trap for Single Particles
Schroeder, Charles
opposing laminar streams converge, thereby generating a planar extensional flow with a fluid stagnation-based technique for particle trapping and manipulation based solely on hydrodynamic fluid flow. Using this method of the flow field to maintain particle position at the fluid stagnation point. In this manner, particles
Close-Packed Floating Clusters: Granular Hydrodynamics Beyond the Freezing Point? Baruch Meerson,1
Meerson, Baruch
Close-Packed Floating Clusters: Granular Hydrodynamics Beyond the Freezing Point? Baruch Meerson,1 a simple explanation for the success of NSGH beyond the freezing point. DOI: 10.1103/PhysRevLett.91 the packing fraction approaches the freezing point value f ' 0:49 (in three dimensions) or 0.69 (in two
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
About Contacts Advertise Site Experts from the University of Illinois have produced a manufacturing
Rogers, John A.
electricity Danny Bradbury, BusinessGreen, 09 Oct 2008 a d v e r t i s e m e n t SEARCH BusinessGreen White & Components UK boffins warm to cheaper solar power Durham University unveils £6.3m project to make low offers ray of light in stock market gloom CDM firm sees share price jump on solid financial performance
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
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.
University Park, Illinois: Energy Resources | Open Energy Information
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Carborundum Universal Ltd | Open Energy Information
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University of Cape Town | Open Energy Information
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University of Delaware Wind | Open Energy Information
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University of Neuchatel | Open Energy Information
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University of New Hampshire | Open Energy Information
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University of California, Berkeley | 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 on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaP a g eWorks -09-0018-CXNuonYuchengRichlands,project activitiesCommerce JumpUniversity of
University of Oldenburg | Open Energy Information
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University of Rhode Island | Open Energy Information
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A Godunov-like point-centered essentially Lagrangian hydrodynamic approach
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Morgan, Nathaniel R.; Waltz, Jacob I.; Burton, Donald E.; Charest, Marc R.; Canfield, Thomas R.; Wohlbier, John G.
2014-10-28T23:59:59.000Z
We present an essentially Lagrangian hydrodynamic scheme suitable for modeling complex compressible flows on tetrahedron meshes. The scheme reduces to a purely Lagrangian approach when the flow is linear or if the mesh size is equal to zero; as a result, we use the term essentially Lagrangian for the proposed approach. The motivation for developing a hydrodynamic method for tetrahedron meshes is because tetrahedron meshes have some advantages over other mesh topologies. Notable advantages include reduced complexity in generating conformal meshes, reduced complexity in mesh reconnection, and preserving tetrahedron cells with automatic mesh refinement. A challenge, however, is tetrahedron meshesmore »do not correctly deform with a lower order (i.e. piecewise constant) staggered-grid hydrodynamic scheme (SGH) or with a cell-centered hydrodynamic (CCH) scheme. The SGH and CCH approaches calculate the strain via the tetrahedron, which can cause artificial stiffness on large deformation problems. To resolve the stiffness problem, we adopt the point-centered hydrodynamic approach (PCH) and calculate the evolution of the flow via an integration path around the node. The PCH approach stores the conserved variables (mass, momentum, and total energy) at the node. The evolution equations for momentum and total energy are discretized using an edge-based finite element (FE) approach with linear basis functions. A multidirectional Riemann-like problem is introduced at the center of the tetrahedron to account for discontinuities in the flow such as a shock. Conservation is enforced at each tetrahedron center. The multidimensional Riemann-like problem used here is based on Lagrangian CCH work [8, 19, 37, 38, 44] and recent Lagrangian SGH work [33-35, 39, 45]. In addition, an approximate 1D Riemann problem is solved on each face of the nodal control volume to advect mass, momentum, and total energy. The 1D Riemann problem produces fluxes [18] that remove a volume error in the PCH discretization. A 2-stage Runge–Kutta method is used to evolve the solution in time. The details of the new hydrodynamic scheme are discussed; likewise, results from numerical test problems are presented.« less
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.
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
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. ______ ...
The Kozai-Lidov mechanism in hydrodynamical disks. II. Effects of binary and disk parameters
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Fu, Wen; Lubow, Stephen H.; Martin, Rebecca G.
2015-07-01T23:59:59.000Z
Martin et al. (2014b) showed that a substantially misaligned accretion disk around one component of a binary system can undergo global damped Kozai–Lidov (KL) oscillations. During these oscillations, the inclination and eccentricity of the disk are periodically exchanged. However, the robustness of this mechanism and its dependence on the system parameters were unexplored. In this paper, we use three-dimensional hydrodynamical simulations to analyze how various binary and disk parameters affect the KL mechanism in hydrodynamical disks. The simulations include the effect of gas pressure and viscosity, but ignore the effects of disk self-gravity. We describe results for different numerical resolutions,more »binary mass ratios and orbital eccentricities, initial disk sizes, initial disk surface density profiles, disk sound speeds, and disk viscosities. We show that the KL mechanism can operate for a wide range of binary-disk parameters. We discuss the applications of our results to astrophysical disks in various accreting systems.« less
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...
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.
Swaddiwudhipong, S; Liu, Z S
2012-01-01T23:59:59.000Z
Finite element method (FEM) suffers from a serious mesh distortion problem when used for high velocity impact analyses. The smooth particle hydrodynamics (SPH) method is appropriate for this class of problems involving severe damages but at considerable computational cost. It is beneficial if the latter is adopted only in severely distorted regions and FEM further away. The coupled smooth particle hydrodynamics - finite element method (SFM) has been adopted in a commercial hydrocode LS-DYNA to study the perforation of Weldox 460E steel and AA5083-H116 aluminum plates with varying thicknesses and various projectile nose geometries including blunt, conical and ogival noses. Effects of the SPH domain size and particle density are studied considering the friction effect between the projectile and the target materials. The simulated residual velocities and the ballistic limit velocities from the SFM agree well with the published experimental data. The study shows that SFM is able to emulate the same failure mechan...
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.
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...
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.
Energy flow between two hydrodynamically coupled particles kept at different effective temperatures
Antoine Bérut; Artyom Petrosyan; Sergio Ciliberto
2015-05-26T23:59:59.000Z
We measure the energy exchanged between two hydrodynamically coupled micron-sized Brownian particles trapped in water by two optical tweezers. The system is driven out of equilibrium by random forcing the position of one of the two particles. The forced particle behaves as it has an "effective temperature" higher than that of the other bead. This driving modifies the equilibrium variances and cross-correlation functions of the bead positions: we measure an energy flow between the particles and an instantaneous cross-correlation, proportional to the effective temperature difference between the two particles. A model of the interaction which is based on classical hydrodynamic coupling tensors is proposed. The theoretical and experimental results are in excellent agreement.
The Kozai-Lidov Mechanism in Hydrodynamical Disks - II. Effects of binary and disk parameters
Fu, Wen; Martin, Rebecca G
2015-01-01T23:59:59.000Z
Martin et al. (2014b) showed that a substantially misaligned accretion disk around one component of a binary system can undergo global damped Kozai-Lidov oscillations. During these oscillations, the inclination and eccentricity of the disk are periodically exchanged. However, the robustness of this mechanism and its dependence on the system parameters were unexplored. In this paper, we use three-dimensional hydrodynamical simulations to analyze how various binary and disk parameters affect the Kozai-Lidov mechanism in hydrodynamical disks. The simulations include the effect of gas pressure and viscosity, but ignore the effects of disk self-gravity. We describe results for different numerical resolutions, binary mass ratios and orbital eccentricities, initial disk sizes, initial disk surface density profiles, disk sound speeds, and disk viscosities. We show that the Kozai-Lidov mechanism can operate for a wide range of binary-disk parameters. We discuss the applications of our results to astrophysical disks in...
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.
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.
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.
Solving 3D relativistic hydrodynamical problems with WENO discontinuous Galerkin methods
Bugner, Marcus; Bernuzzi, Sebastiano; Weyhausen, Andreas; Bruegmann, Bernd
2015-01-01T23:59:59.000Z
Discontinuous Galerkin (DG) methods coupled to WENO algorithms allow high order convergence for smooth problems and for the simulation of discontinuities and shocks. In this work, we investigate WENO-DG algorithms in the context of numerical general relativity, in particular for general relativistic hydrodynamics. We implement the standard WENO method at different orders, a compact (simple) WENO scheme, as well as an alternative subcell evolution algorithm. To evaluate the performance of the different numerical schemes, we study non-relativistic, special relativistic, and general relativistic testbeds. We present the first three-dimensional simulations of general relativistic hydrodynamics, albeit for a fixed spacetime background, within the framework of WENO-DG methods. The most important testbed is a single TOV-star in three dimensions, showing that long term stable simulations of single isolated neutron stars can be obtained with WENO-DG methods.
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.
Analysis and verification of a three-dimensional hydrodynamic numerical model
Abraham, David Daniel
1991-01-01T23:59:59.000Z
of Advisory Committee: Dr. W. P. James A three-dimensional hydrodynamic numerical model (RMA10) was analyized and verified. The verification process involved the comparison of model and measured water surface elevations, velocities, and depth averaged... velocities. The verification (measured) data were obtained from a large (200 cfs) flume. The numerical grid was set up such that the spacial location of the computational points was as close as practical to that of the measured data. The model computed...
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...
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.... Elevations for all wells were checked on topographic maps published by U. S. Geological Survey. Drill-stem tests from Gas Draw field and the surrounding nine township area are available from industry sources. About 100 repre- sentative tests were from...
A Newton-Krylov Solver for Implicit Solution of Hydrodynamics in Core Collapse Supernovae
Reynolds, D R; Swesty, F D; Woodward, C S
2008-06-12T23:59:59.000Z
This paper describes an implicit approach and nonlinear solver for solution of radiation-hydrodynamic problems in the context of supernovae and proto-neutron star cooling. The robust approach applies Newton-Krylov methods and overcomes the difficulties of discontinuous limiters in the discretized equations and scaling of the equations over wide ranges of physical behavior. We discuss these difficulties, our approach for overcoming them, and numerical results demonstrating accuracy and efficiency of the method.
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.
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.
Simulation study of the effect of hydrodynamic forces on oil recovery
Idrobo Hurtado, Eduardo Alejandro
1992-01-01T23:59:59.000Z
of entrapment was also investigated. DEDICATION To my wife Angela Maria and my daughter Maria Angelica for their undying love, support, and patience. To my parents: Eduardo Idrobo Mazorra y Maruja Hurtado de Idmbo. ACKNOWLEDGEMENTS I would like to thank... Transmissibility of 0. 2 md-d/stb 52 52 Hydrodynamic Case when a Fault is Present. . . . . . . . . . . 53 CHAPTER V ? SUMMARY AND CONCLUSIONS . Summary. Conclusions NOMENCLATURE REFERENCES . VITA Page 61 . . . 61 . . 62 65 67 69 LIST OF TABLES...
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.
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.
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.
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 ...
Mosher, Phillip Andrew
1993-01-01T23:59:59.000Z
Hybrid (combination hydrostatic and hydrodynamic) bearings have been proposed for use as a support element in cryogenic high speed turbomachinery for primary and auxiliary space power applications because of their long lifetime, low friction...
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...
Alexeev, Boris V
2008-01-01T23:59:59.000Z
Quantum solitons are discovered with the help of generalized quantum hydrodynamics (GQH). The solitons have the character of the stable quantum objects in the self consistent electric field. These effects can be considered as explanation of the existence of lightning balls. The delivered theory demonstrates the great possibilities of the generalized quantum hydrodynamics in investigation of the quantum solitons. The paper can be considered also as comments and prolongation of the materials published in the known author`s monograph (Boris V. Alexeev, Generalized Boltzmann Physical Kinetics. Elsevier. 2004). The theory leads to solitons as typical formations in the generalized quantum hydrodynamics. Key words: Foundations of the theory of transport processes; The theory of solitons; Generalized hydrodynamic equations; Foundations of quantum mechanics; The theory of lightning balls. PACS: 67.55.Fa, 67.55.Hc
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...
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.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Doss, F. W.; Kline, J. L.; Flippo, K. A.; Perry, T. S.; DeVolder, B. G.; Tregillis, I.; Loomis, E. N.; Merritt, E. C.; Murphy, T. J.; Welser-Sherrill, L.; et al
2015-04-17T23:59:59.000Z
An indirectly-driven shock tube experiment fielded on the National Ignition Facility (NIF) was used to create a high-energy-density hydrodynamics platform at unprecedented scale. Scaling up a shear-induced mixing experiment previously fielded at OMEGA, the NIF shear platform drives 130 ?m/ns shocks into a CH foam-filled shock tube (~ 60 mg/cc) with interior dimensions of 1.5 mm diameter and 5 mm length. The pulse-shaping capabilities of the NIF are used to extend the drive for >10 ns, and the large interior tube volumes are used to isolate physics-altering edge effects from the region of interest. The scaling of the experiment tomore »the NIF allows for considerable improvement in maximum driving time of hydrodynamics, in fidelity of physics under examination, and in diagnostic clarity. Details of the experimental platform and post-shot simulations used in the analysis of the platform-qualifying data are presented. Hydrodynamic scaling is used to compare shear data from OMEGA with that from NIF, suggesting a possible change in the dimensionality of the instability at late times from one platform to the other.« less
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.
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.
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.
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.
3D hydrodynamical and radiative transfer modeling of Eta Carinae's colliding winds
Madura, Thomas I; Gull, Theodore R; Kruip, Chael J H; Paardekooper, Jan-Pieter; Icke, Vincent
2015-01-01T23:59:59.000Z
We present results of full 3D hydrodynamical and radiative transfer simulations of the colliding stellar winds in the massive binary system Eta Carinae. We accomplish this by applying the SimpleX algorithm for 3D radiative transfer on an unstructured Voronoi-Delaunay grid to recent 3D smoothed particle hydrodynamics (SPH) simulations of the binary colliding winds. We use SimpleX to obtain detailed ionization fractions of hydrogen and helium, in 3D, at the resolution of the original SPH simulations. We investigate several computational domain sizes and Luminous Blue Variable primary star mass-loss rates. We furthermore present new methods of visualizing and interacting with output from complex 3D numerical simulations, including 3D interactive graphics and 3D printing. While we initially focus on Eta Car, the methods employed can be applied to numerous other colliding wind (WR 140, WR 137, WR 19) and dusty 'pinwheel' (WR 104, WR 98a) binary systems. Coupled with 3D hydrodynamical simulations, SimpleX simulatio...
A point-centered arbitrary Lagrangian Eulerian hydrodynamic approach for tetrahedral meshes
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Morgan, Nathaniel R.; Waltz, Jacob I.; Burton, Donald E.; Charest, Marc R.; Canfield, Thomas R.; Wohlbier, John G.
2015-06-01T23:59:59.000Z
We present a three dimensional (3D) arbitrary Lagrangian Eulerian (ALE) hydrodynamic scheme suitable for modeling complex compressible flows on tetrahedral meshes. The new approach stores the conserved variables (mass, momentum, and total energy) at the nodes of the mesh and solves the conservation equations on a control volume surrounding the point. This type of an approach is termed a point-centered hydrodynamic (PCH) method. The conservation equations are discretized using an edge-based finite element (FE) approach with linear basis functions. All fluxes in the new approach are calculated at the center of each tetrahedron. A multidirectional Riemann-like problem is solved atmore »the center of the tetrahedron. The advective fluxes are calculated by solving a 1D Riemann problem on each face of the nodal control volume. A 2-stage Runge–Kutta method is used to evolve the solution forward in time, where the advective fluxes are part of the temporal integration. The mesh velocity is smoothed by solving a Laplacian equation. The details of the new ALE hydrodynamic scheme are discussed. Results from a range of numerical test problems are presented.« less
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.
University Bookstore University Art Store
Sorin, Eric J.
& Pub* Nugget Express* Squeeze Me Starbucks* The Outpost Grill* University Student Union Carl's Jr El Ground Floor Coffee House Central Park Coffee House University Library Starbucks* DINING www
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...