Viscosity of a nucleonic fluid
Aram Z. Mekjian
2012-03-21T23:59:59.000Z
The viscosity of nucleonic matter is studied both classically and in a quantum mechanical description. The collisions between particles are modeled as hard sphere scattering as a baseline for comparison and as scattering from an attractive square well potential. Properties associated with the unitary limit are developed which are shown to be approximately realized for a system of neutrons. The issue of near perfect fluid behavior of neutron matter is remarked on. Using some results from hard sphere molecular dynamics studies near perfect fluid behavior is discussed further.
Viscosity of High Energy Nuclear Fluids
V. Parihar; A. Widom; D. Drosdoff; Y. N. Srivastava
2007-03-15T23:59:59.000Z
Relativistic high energy heavy ion collision cross sections have been interpreted in terms of almost ideal liquid droplets of nuclear matter. The experimental low viscosity of these nuclear fluids have been of considerable recent quantum chromodynamic interest. The viscosity is here discussed in terms of the string fragmentation models wherein the temperature dependence of the nuclear fluid viscosity obeys the Vogel-Fulcher-Tammann law.
Quartz resonator fluid density and viscosity monitor
Martin, Stephen J. (Albuquerque, NM); Wiczer, James J. (Albuquerque, NM); Cernosek, Richard W. (Albuquerque, NM); Frye, Gregory C. (Cedar Crest, NM); Gebert, Charles T. (Albuquerque, NM); Casaus, Leonard (Bernalillo, NM); Mitchell, Mary A. (Tijeras, NM)
1998-01-01T23:59:59.000Z
A pair of thickness-shear mode resonators, one smooth and one with a textured surface, allows fluid density and viscosity to be independently resolved. A textured surface, either randomly rough or regularly patterned, leads to trapping of liquid at the device surface. The synchronous motion of this trapped liquid with the oscillating device surface allows the device to weigh the liquid; this leads to an additional response that depends on liquid density. This additional response enables a pair of devices, one smooth and one textured, to independently resolve liquid density and viscosity; the difference in responses determines the density while the smooth device determines the density-viscosity product, and thus, the pair determines both density and viscosity.
Viscosity of Quantum Hall Fluids J. E. Avron
Viscosity of Quantum Hall Fluids J. E. Avron Department of Physics, Technion, 32000 Haifa, Israel R April 25, 1997 Abstract The viscosity of quantum fluids with an energy gap at zero temperature is non of the parameter space). For a quantum Hall fluid on two dimensional tori this viscosity is computed. In this case
Kostic, Milivoje M.
46-1 46.1 Shear Viscosity An important mechanical property of fluids is viscosity. Physical systems involve fluid flow and are controlled to some degree by fluid viscosity. Viscosity is the tendency, viscosity is related to molecular dif- fusion and depends on the interactions between molecules or
Viscosity of an ideal relativistic quantum fluid: A perturbative study
Giorgio Torrieri
2012-02-14T23:59:59.000Z
We show that a quantized ideal fluid will generally exhibit a small but non-zero viscosity due to the backreaction of quantum soundwaves on the background. We use an effective field theory expansion to estimate this viscosity to first order in perturbation theory. We discuss our results, and whether this estimate can be used to obtain a more model-independent estimate of the "quantum bound" on the viscosity of physical systems
Non-invasive fluid density and viscosity measurement
Sinha, Dipen N. (Los Alamos, NM)
2012-05-01T23:59:59.000Z
The noninvasively measurement of the density and viscosity of static or flowing fluids in a section of pipe such that the pipe performs as the sensing apparatus, is described. Measurement of a suitable structural vibration resonance frequency of the pipe and the width of this resonance permits the density and viscosity to be determined, respectively. The viscosity may also be measured by monitoring the decay in time of a vibration resonance in the pipe.
Viscosity, entropy and the viscosity to entropy density ratio; how perfect is a nucleonic fluid?
Aram Z. Mekjian
2010-09-29T23:59:59.000Z
The viscosity of hadronic matter is studied using a classical evaluation of the scattering angle and a quantum mechanical discussion based on phase shifts from a potential. Semi classical limits of the quantum theory are presented. A hard sphere and an attractive square well potential step are each considered as well as the combined effects of both. The lowest classical value of the viscosity for an attractive potential is shown to be a hard sphere limit. The high wave number-short wavelength limits of the quantum result have scaling laws associated with it for both the viscosity and entropy. These scaling laws are similar to the Fraunhoher diffraction increase for the hard sphere geometric cross section. Specific examples for nuclear collisions are given. The importance of the nuclear tensor force and hard core is mentioned. The viscosity (eta), entropy density (s) and eta/s ratio are calculated for a gas of dilute neutrons in the unitary limit of large scattering length. Away from the unitary limit, the ratio of the interaction radius or the scattering length to the interparticle spacing introduces a variable y besides the fugacity z. The isothermal compressibility is shown to impose important constraints. The results for eta/s are compared to the AdS/CFT string theory minimum of (1/4Pi)hbar/kb to see how close a nucleonic gas is to being a perfect fluid. The eta/s ~1hbar/kb for a neutron gas in its unitary limit. The eta/s 3hbar/kb treating the nuclear scattering as billiard ball collisions. The minimum eta/s for a neutron gas occurs in regions of negative isothermal compressibility and high fugacity where higher virial terms are important. In a neutron-proton system higher virial terms are associated with a liquid-gas phase transition and critical opalescent phenomena.The type of flow-laminar,vortex, turbulent- is investigated.
Textured-surface quartz resonator fluid density and viscosity monitor
Martin, Stephen J. (Albuquerque, NM); Wiczer, James J. (Albuquerque, NM); Cernosek, Richard W. (Albuquerque, NM); Frye, Gregory C. (Cedar Crest, NM); Gebert, Charles T. (Albuquerque, NM); Casaus, Leonard (Bernalillo, NM); Mitchell, Mary A. (Tijeras, NM)
1998-08-25T23:59:59.000Z
A pair of thickness-shear mode resonators, one smooth and one with a textured surface, allows fluid density and viscosity to be independently resolved. A textured surface, either randomly rough or regularly patterned, leads to trapping of liquid at the device surface. The synchronous motion of this trapped liquid with the oscillating device surface allows the device to weigh the liquid; this leads to an additional response that depends on liquid density. This additional response enables a pair of devices, one smooth and one textured, to independently resolve liquid density and viscosity; the difference in responses determines the density while the smooth device determines the density-viscosity product, and thus, the pair determines both density and viscosity.
Tirtaatmadja, Viyada
2007-01-23T23:59:59.000Z
The dynamics of drop formation and pinch-off have been investigated for a series of low viscosity elastic fluids possessing similar shear viscosities, but differing substantially in elastic properties. On initial approach ...
The measurement of cross-linked fracture fluid viscosity using a pipe viscometer
Vermaelen, John Douglas
1985-01-01T23:59:59.000Z
THE MEASUREMENT OF CROSS-LINKED FRACTURE FLUID VISCOSITY USING A PIPE VISCOMETER A Thesis by JOHN DOUGLAS VERMAELEN Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirements for the degr ee..., B. S. , Texas A&M University Chairman of Advisory Committee: Dr. Stephen A. Holditch Due to the increased importance of hydraulic fracture ing as a means of well stimulation, there is a need for a better understanding of the viscous behavior of a...
The measurement of cross-linked fracture fluid viscosity using a pipe viscometer
Vermaelen, John Douglas
1985-01-01T23:59:59.000Z
THE MEASUREMENT OF CROSS-LINKED FRACTURE FLUID VISCOSITY USING A PIPE VISCOMETER A Thesis by JOHN DOUGLAS VERMAELEN Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirements for the degr ee... of MASTER OF SCIENCE December 1985 Major Subject: Petr oleum Engineering THE MEASUREMENT OF CROSS-LINKED FRACTURE FLUID VISCOSITY USING A PIPE VISCOMETER A Thesis by JOHN DOUGLAS VERMAELEN Approved as to style and content by: Stephen A. Holditch...
Micromechanical transient sensor for measuring viscosity and density of a fluid
Thundat, Thomas G. (Knoxville, TN); Oden, Patrick I. (Plano, TX); Warmack, Robert J. (Knoxville, TN); Finot, Eric Laurent (Torcy, FR)
2001-01-01T23:59:59.000Z
A method and apparatus for measuring the viscosity and/or specific density of a fluid utilizes a microcantilever vibrated in the analyte fluid. The source of vibration is switched on and off and the transient behavior or decay in amplitude of the vibration is monitored. The method is particularly useful for the measurement of process conditions in remote locations in real time.
Influence of viscosity contrast on buoyantly unstable miscible fluids in porous media
Pramanik, Satyajit; Mishra, Manoranjan
2015-01-01T23:59:59.000Z
The influence of viscosity contrast on buoyantly unstable miscible fluids in a porous medium is investigated through a linear stability analysis (LSA) as well as direct numerical simulations (DNS). The linear stability method implemented in this paper is based on an initial value approach, which helps to capture the onset of instability more accurately than the quasi-steady state analysis. In the absence of displacement, we show that viscosity contrast delays the onset of instability in buoyantly unstable miscible fluids. Further, it is observed that suitably choosing the viscosity contrast and injection velocity a gravitationally unstable miscible interface can be stabilized completely. Through LSA we draw a phase diagram, which shows three distinct stability regions in a parameter space spanned by the displacement velocity and the viscosity contrast. DNS are performed corresponding to parameters from each regime and the results obtained are in accordance with the linear stability results. Moreover, the conv...
Computer simulation of effective viscosity of fluid-proppant mixture used in hydraulic fracturing
Kuzkin, Vitaly A; Linkov, Aleksandr M
2013-01-01T23:59:59.000Z
The paper presents results of numerical experiments performed to evaluate the effective viscosity of a fluid-proppant mixture, used in hydraulic fracturing. The results, obtained by two complimenting methods (the particle dynamics and the smoothed particle hydrodynamics), coincide to the accuracy of standard deviation. They provide an analytical equation for the dependence of effective viscosity on the proppant concentration, needed for numerical simulation of the hydraulic fracture propagation.
Coalescence of Low-Viscosity Fluids in Air
Sarah C. Case
2008-09-09T23:59:59.000Z
An electrical method is used to study the early stages of coalescence of two low-viscosity drops. A drop of aqueous NaCl solution is suspended in air above a second drop of the same solution which is grown until the drops touch. At that point a rapidly widening bridge forms between them. By measuring the resistance and capacitance of the system during this coalescence event, one can obtain information about the time dependence of the characteristic bridge radius and its characteristic height. At early times, a new asymptotic regime is observed that is inconsistent with previous theoretical predictions. The measurements at several drop radii and approach velocities are consistent with a model in which the two liquids coalesce with a slightly deformed interface.
Cosmological model with viscosity media (dark fluid) described by an effective equation of state
J. Ren; Xin He Meng
2005-11-07T23:59:59.000Z
A generally parameterized equation of state (EOS) is investigated in the cosmological evolution with bulk viscosity media modelled as dark fluid, which can be regarded as a unification of dark energy and dark matter. Compared with the case of the perfect fluid, this EOS has possessed four additional parameters, which can be interpreted as the case of the non-perfect fluid with time-dependent viscosity or the model with variable cosmological constant. From this general EOS, a completely integrable dynamical equation to the scale factor is obtained with its solution explicitly given out. (i) In this parameterized model of cosmology, for a special choice of the parameters we can explain the late-time accelerating expansion universe in a new view. The early inflation, the median (relatively late time) deceleration, and the recently cosmic acceleration may be unified in a single equation. (ii) A generalized relation of the Hubble parameter scaling with the redshift is obtained for some cosmology interests. (iii) By using the SNe Ia data to fit the effective viscosity model we show that the case of matter described by $p=0$ plus with effective viscosity contributions can fit the observational gold data in an acceptable level
Avadhany, Shakeel N
2009-01-01T23:59:59.000Z
This investigation seeks to investigate the relationship of kinematic fluid viscosity to the effective power transduction seen by a hydraulic motor. Applications of this research specifically relate to energy recovery from ...
Bastian, Peter Andrae
1983-01-01T23:59:59.000Z
THE MEASUREMENT OF THE VISCOSITY OF CROSS-LINKED FRACTURE FLUIDS USING A FANN MODEL SOC ROTATIONAL VISCOMETER A Thesis by PETER ANDRAE 8ASTIAN Submitted to the Graduate College of Texas ARM University in partial fulfillment... of the requirements for the degree nf MASTER OF SCIENCE December 1983 Major Subject: Petroleum Engineering THE MEASUREMENT OF THE VISCOSITY OF CROSS-LINKED FRACTURE FLUIDS USING A FANN MODEL SOC ROTATIONAL VISCOMETER A Thesis by PETER ANDRAE BASTIAN Approved...
Heller, John P. (Socorro, NM); Dandge, Dileep K. (Socorro, NM)
1986-01-01T23:59:59.000Z
Solvent-type flooding fluids comprising light hydrocarbons in the range of ethane to hexane (and mixtures thereof) are used to displace crude oil in formations having temperatures of about 20 degrees to about 150 degrees Centigrade and pressures above about 650 psi, the light hydrocarbons having dissolved therein from about 0.05% to about 3% of an organotin compound of the formula R.sub.3 SnF where each R is independently an alkyl, aryl or alkyaryl group from 3 to 12 carbon atoms. Under the pressures and temperatures described, the organotin compounds become pentacoordinated and linked through the electronegative bridges, forming polymers within the light hydrocarbon flooding media to render them highly viscous. Under ambient conditions, the viscosity control agents will not readily be produced from the formation with either crude oil or water, since they are insoluble in the former and only sparingly soluble in the latter.
Buckingham, Michael
interactions. Designated the VGS theory, the new model returns dispersion curves that differ mildly from those sediments Michael J. Buckinghama Marine Physical Laboratory, Scripps Institution of Oceanography, University granular material, such as a marine sediment, is extended to include the effects of the viscosity
Buoyant mixing of miscible fluids of varying viscosities in vertical tubes M. Debacq,a)
Hinch, John
engineering,10 fire propagation in vertical shafts,11 drilling and completion fluids in petroleum engi reported by other authors.10,11 Baird et al.10 studied the mixing of a small vol- ume of heavy salt
Viscosity measuring using microcantilevers
Oden, Patrick Ian (Plano, TX)
2001-01-01T23:59:59.000Z
A method for the measurement of the viscosity of a fluid uses a micromachined cantilever mounted on a moveable base. As the base is rastered while in contact with the fluid, the deflection of the cantilever is measured and the viscosity determined by comparison with standards.
Effectiveness of continuous hot-fluid stimulation of high viscosity oil wells
Oetama, Teddy
1983-01-01T23:59:59.000Z
Chairman of Advisory Committee: Dr. R. A. Norse Continuous hot fluid stimulation methods, cycling and mid-point injection, were numerically investigated in this study. The methods consist of a wellbore heating process involving the injection of hot oil... into a portion of the wellbore and production of fluids from another section of the wellbore. The methods were compared witn downhole, con- ductive heating and producing oil from an unheated well. A stabilized temperature of the producing interval...
A numerical study of fluids with pressure dependent viscosity flowing through a rigid porous media
Nakshatrala, K B
2009-01-01T23:59:59.000Z
In this paper we consider modifications to Darcy's equation wherein the drag coefficient is a function of pressure, which is a realistic model for technological applications like enhanced oil recovery and geological carbon sequestration. We first outline the approximations behind Darcy's equation and the modifications that we propose to Darcy's equation, and derive the governing equations through a systematic approach using mixture theory. We then propose a stabilized mixed finite element formulation for the modified Darcy's equation. To solve the resulting nonlinear equations we present a solution procedure based on the consistent Newton-Raphson method. We solve representative test problems to illustrate the performance of the proposed stabilized formulation. One of the objectives of this paper is also to show that the dependence of viscosity on the pressure can have a significant effect both on the qualitative and quantitative nature of the solution.
Iver Brevik
2012-11-23T23:59:59.000Z
A bulk viscosity is introduced in the formalism of modified gravity. It is shown that, on the basis of a natural scaling law for the viscosity, a simple solution can be found for quantities such as the Hubble parameter and the energy density. These solutions may incorporate a viscosity-induced Big Rip singularity. By introducing a phase transition in the cosmic fluid, the future singularity can nevertheless in principle be avoided.
Hall viscosity from gauge/gravity duality
Omid Saremi; Dam Thanh Son
2011-03-24T23:59:59.000Z
In (2+1)-dimensional systems with broken parity, there exists yet another transport coefficient, appearing at the same order as the shear viscosity in the hydrodynamic derivative expansion. In condensed matter physics, it is referred to as "Hall viscosity". We consider a simple holographic realization of a (2+1)-dimensional isotropic fluid with broken spatial parity. Using techniques of fluid/gravity correspondence, we uncover that the holographic fluid possesses a nonzero Hall viscosity, whose value only depends on the near-horizon region of the background. We also write down a Kubo's formula for the Hall viscosity. We confirm our results by directly computing the Hall viscosity using the formula.
Viscosity of alumina nanoparticles dispersed in car engine coolant
Kole, Madhusree; Dey, T.K. [Thermophysical Measurements Laboratory, Cryogenic Engineering Centre, Indian Institute of Technology, Kharagpur 721 302 (India)
2010-09-15T23:59:59.000Z
The present paper, describes our experimental results on the viscosity of the nanofluid prepared by dispersing alumina nanoparticles (<50 nm) in commercial car coolant. The nanofluid prepared with calculated amount of oleic acid (surfactant) was tested to be stable for more than 80 days. The viscosity of the nanofluids is measured both as a function of alumina volume fraction and temperature between 10 and 50 C. While the pure base fluid display Newtonian behavior over the measured temperature, it transforms to a non-Newtonian fluid with addition of a small amount of alumina nanoparticles. Our results show that viscosity of the nanofluid increases with increasing nanoparticle concentration and decreases with increase in temperature. Most of the frequently used classical models severely under predict the measured viscosity. Volume fraction dependence of the nanofluid viscosity, however, is predicted fairly well on the basis of a recently reported theoretical model for nanofluids that takes into account the effect of Brownian motion of nanoparticles in the nanofluid. The temperature dependence of the viscosity of engine coolant based alumina nanofluids obeys the empirical correlation of the type: log ({mu}{sub nf}) = A exp(BT), proposed earlier by Namburu et al. (author)
Carl H. Gibson
2000-12-18T23:59:59.000Z
Self-gravitational structure formation theory for astrophysics and cosmology is revised using nonlinear fluid mechanics. Gibson's 1996-2000 theory balances fluid mechanical forces with gravitational forces and density diffusion with gravitational diffusion at critical viscous, turbulent, magnetic, and diffusion length scales termed Schwarz scales. Instability occurs for scales larger than the largest Schwarz scale rather than only for scales larger than the acoustic scale introduced by Jeans 1902. From the new theory, the inner-halo-dark-matter of galaxies consists of dark proto-globular-star-cluster (PGC) clumps of small-planetary-mass objects called primordial fog particles (PFPs) formed soon after decoupling at 300,000 years. PFPs explain Schild's 1996 "rogue planets >... likely to be the missing mass" of a quasar lens-galaxy. WIMP dark matter fluid is super-diffusive and fragments at large L_SD scales to form outer-galaxy-halos. In the beginning of structure formation 30,000 years after the Big Bang the viscous Schwarz scale L_SV matched the horizon scale L_H at proto-galaxy-supercluster masses, decreasing to proto-galaxy fragments at 300,000 years. WIMP diffusivities from observed outer-halo (L_SD) scales indicate WIMP particle masses in the neutrino rather than neutralino range.
Early dissipation and viscosity
Piotr Bozek
2008-04-24T23:59:59.000Z
We consider dissipative phenomena due to the relaxation of an initial anisotropic local pressure in the fireball created in relativistic heavy-ion collisions, both for the Bjorken boost-invariant case and for the azimuthally symmetric radial expansion with boost-invariance. The resulting increase of the entropy can be counterbalanced by a suitable retuning of the initial temperature. An increase of the transverse collective flow is observed. The influence of the shear viscosity on the longitudinal expansion is also studied. Viscosity reduces the cooling rate from the longitudinal work and counteracts the pressure gradients that accelerate the longitudinal flow.
Gas Viscosity at High Pressure and High Temperature
Ling, Kegang
2012-02-14T23:59:59.000Z
, design drilling fluid, and monitor gas movement in well control. Current gas viscosity correlations are derived using measured data at low-moderate pressures and temperatures, and then extrapolated to HPHT. No measured gas viscosities at HPHT...
Viscosity Measurement G.E. Leblanc
Kostic, Milivoje M.
30 Viscosity Measurement G.E. Leblanc McMaster University R.A. Secco The University of Western and Non-Newtonian Fluids l Dimensions and Units of Viscosity l Viscometer Types l Capillary M. Kostic must be supplied (1) to create viscous flow units by breaking bonds between atoms and molecules, and (2
Duangthongsuk, Weerapun; Wongwises, Somchai [Fluid Mechanics, Thermal Engineering and Multiphase Flow Research Lab. (FUTURE), Department of Mechanical Engineering, King Mongkut's University of Technology Thonburi, 126 Bangmod, Bangkok 10140 (Thailand)
2009-04-15T23:59:59.000Z
Nanofluid is an innovative heat transfer fluid with superior potential for enhancing the heat transfer performance of conventional fluids. Many attempts have been made to investigate its thermal conductivity and viscosity, which are important thermophysical properties. No definitive agreements have emerged, however, about these properties. This article reports the thermal conductivity and dynamic viscosity of nanofluids experimentally. TiO{sub 2} nanoparticles dispersed in water with volume concentration of 0.2-2 vol.% are used in the present study. A transient hot-wire apparatus is used for measuring the thermal conductivity of nanofluids whereas the Bohlin rotational rheometer (Malvern Instrument) is used to measure the viscosity of nanofluids. The data are collected for temperatures ranging from 15 C to 35 C. The results show that the measured viscosity and thermal conductivity of nanofluids increased as the particle concentrations increased and are higher than the values of the base liquids. Furthermore, thermal conductivity of nanofluids increased with increasing nanofluid temperatures and, conversely, the viscosity of nanofluids decreased with increasing temperature of nanofluids. Moreover, the measured thermal conductivity and viscosity of nanofluids are quite different from the predicted values from the existing correlations and the data reported by other researchers. Finally, new thermophysical correlations are proposed for predicting the thermal conductivity and viscosity of nanofluids. (author)
Effective shear viscosity and dynamics of suspensions of micro-swimmers at moderate concentrations
Constantin, Lipnikov [Los Alamos National Laboratory; Gyrya, V [PENNSYLVANIA STATE UNIV.; Aronson, I [ANL; Berlyand, L [PENNSYLVANIA STATE UNIV.
2009-01-01T23:59:59.000Z
Recently, there have been a number of experimental studies suggesting that a suspension of self-propelled bacteria (microswimmers in general) may have an effective viscosity significantly smaller than the viscosity of the ambient fluid. This is in sharp contrast with suspensions of hard passive inclusions, whose presence always increases the viscosity. Here we present a 2D model for a suspension of microswimmers in a fluid and analyze it analytically in the dilute regime (no swimmer-swimmer interactions) and numerically using a Mimetic Finite Difference discretization. Our analysis shows that in the dilute regime the effective shear viscosity is not affected by self-propulsion. But at the moderate concentrations (due to swimmer-swimmer interactions) the effective viscosity decreases linearly as a function of the propulsion strength of the swimmers. These findings prove that (i) a physically observable decrease of viscosity for a suspension of self-propelled bacteria can be explained purely by hydrodynamic interactions and (ii) self-propulsion and interaction of swimmers are both essential to the reduction of the effective shear viscosity. We performed a number of numerical experiments analyzing the dynamics of swimmers resulting from pairwise interactions. The numerical results agree with the physically observed phenomena (e.g., attraction of swimmer to swimmer and swimmer to the wall). This is viewed as an additional validation of the model and the numerical scheme.
Viscosity and dissipation - early stages
P. Bozek
2009-01-15T23:59:59.000Z
A very early start up time of the hydrodynamic evolution is needed in order to reproduce observations from relativistic heavy-ion collisions experiments. At such early times the systems is still not locally equilibrated. Another source of deviations from local equilibrium is the viscosity of the fluid. We study these effects at very early times to obtain a dynamical prescription for the transition from an early 2-dimensional expansion to a nearly equilibrated 3-dimensional expansion at latter stages. The role of viscosity at latter stages of the evolution is also illustrated.
Effective Viscosity of a Dilute Suspension of Membrane-bound Inclusions
Mark L. Henle; Alex J. Levine
2008-08-14T23:59:59.000Z
When particulate suspensions are sheared, perturbations in the shear flows around the rigid particles increase the local energy dissipation, so that the viscosity of the suspension is effectively higher than that of the solvent. For bulk (three-dimensional) fluids, understanding this viscosity enhancement is a classic problem in hydrodynamics that originated over a century ago with Einstein's study of a dilute suspension of spherical particles. \\cite{Einstein1} In this paper, we investigate the analogous problem of the effective viscosity of a suspension of disks embedded in a two-dimensional membrane or interface. Unlike the hydrodynamics of bulk fluids, low-Reynolds number membrane hydrodynamics is characterized by an inherent length scale generated by the coupling of the membrane to the bulk fluids that surround it. As a result, we find that the size of the particles in the suspension relative to this hydrodynamic length scale has a dramatic effect on the effective viscosity of the suspension. Our study also helps to elucidate the mathematical tools needed to solve the mixed boundary value problems that generically arise when considering the motion of rigid inclusions in fluid membranes.
Scott Pratt; Kerstin Paech
2006-04-03T23:59:59.000Z
A variety of physical phenomena can lead to viscous effects. In this talk we review several sources of shear and bulk viscosity with an emphasis on the bulk viscosity associated with chiral restoration. We show that in the limit of a second order phase transition, the viscosity peaks in a singularity at the critical point.
Thermal relics in cosmology with bulk viscosity
A. Iorio; G. Lambiase
2014-11-28T23:59:59.000Z
In this paper we discuss some consequences of cosmological models in which the primordial cosmic matter is described by a relativistic imperfect fluid. The latter takes into account the dissipative effects (bulk viscosity) arising from different cooling rates of the fluid components in the expanding Universe. We discuss, in particular, the effects of the bulk viscosity on Big Bang Nucleosynthesis and on the thermal relic abundance of particles, looking at recent results of PAMELA experiment. The latter has determined an anomalous excess of positron events, that cannot be explained by the conventional cosmology and particle physics.
Charm contribution to bulk viscosity
M. Laine; Kiyoumars A. Sohrabi
2015-02-24T23:59:59.000Z
In the range of temperatures reached in future heavy ion collision experiments, hadronic pair annihilations and creations of charm quarks may take place within the lifetime of the plasma. As a result, charm quarks may increase the bulk viscosity affecting the early stages of hydrodynamic expansion. Assuming thermalization, we estimate the charm contribution to bulk viscosity within the same effective kinetic theory framework in which the light parton contribution has been computed previously. The time scale at which this physics becomes relevant is related to the width of the transport peak associated with the trace anomaly correlator, and is found to be 600 MeV.
Method for measuring liquid viscosity and ultrasonic viscometer
Sheen, Shuh-Haw (Naperville, IL); Lawrence, William P. (Downers Grove, IL); Chien, Hual-Te (Naperville, IL); Raptis, Apostolos C. (Downers Grove, IL)
1994-01-01T23:59:59.000Z
An ultrasonic viscometer and method for measuring fluid viscosity are provided. Ultrasonic shear and longitudinal waves are generated and coupled to the fluid. Reflections from the generated ultrasonic shear and longitudinal waves are detected. Phase velocity of the fluid is determined responsive to the detected ultrasonic longitudinal waves reflections. Viscosity of the fluid is determined responsive to the detected ultrasonic shear waves reflections. Unique features of the ultrasonic viscometer include the use of a two-interface fluid and air transducer wedge to measure relative signal change and to enable self calibration and the use of a ratio of reflection coefficients for two different frequencies to compensate for environmental changes, such as temperature.
Influence of Liquid Viscosity on Droplet Impingement on Superhydrophobic Surfaces
Pearson, John T; Webb, Brent W
2010-01-01T23:59:59.000Z
This fluid dynamics video describes droplet impingement experiments performed on superhydrophobic surfaces. When droplets of pure water are impinged upon superhydrophobic surfaces, a region of thin coherent jets are observed for Weber numbers between 5 and 15. Also, peripheral splashing is observed for Weber numbers above about 200. When the viscosity of the droplet is increased by mixing glycerol with the water, the thin jets are not observed and peripheral splashing is delayed somewhat. In the Weber number range where pure water droplets are observed to splash peripherally, the water/glycerol droplets are observed to have two-pronged jets.
Bulk viscosity in heavy ion collision
Victor Roy; A. K. Chaudhuri
2012-01-20T23:59:59.000Z
The effect of a temperature dependent bulk viscosity to entropy density ratio~($\\zeta/s$) along with a constant shear viscosity to entropy density ratio~($\\eta/s$) on the space time evolution of the fluid produced in high energy heavy ion collisions have been studied in a relativistic viscous hydrodynamics model. The boost invariant Israel-Stewart theory of causal relativistic viscous hydrodynamics is used to simulate the evolution of the fluid in 2 spatial and 1 temporal dimension. The dissipative correction to the freezeout distribution for bulk viscosity is calculated using Grad's fourteen moment method. From our simulation we show that the method is applicable only for $\\zeta/s<0.004$.
Bulk viscosity in nuclear and quark matter: A short review
Hui Dong; Nan Su; Qun Wang
2007-03-05T23:59:59.000Z
The history and recent progresses in the study of bulk viscosity in nuclear and quark matter are reviewed. The constraints from baryon number conservation and electric neutrality in quark matter on particle densities and fluid velocity divergences are discussed.
VISCOSITY OF NEMATIC-CHIRAL MIXTURES AND THEIR ELECTROOPTICAL CHARACTERISTICS
Boyer, Edmond
VISCOSITY OF NEMATIC-CHIRAL MIXTURES AND THEIR ELECTROOPTICAL CHARACTERISTICS Z. M. ELASHVILI, M. D of Georgian SSR, Tbilisi 380086, S. Euli str. 5, USSR Abstract. -- We have measured the viscosity in mixtures that the increase of the viscosity at low additive concentration (Cm
Shear viscosity and spectral function of the quark matter
Masaharu Iwasaki; Hiromasa Ohnishi; Takahiko Fukutome
2006-06-19T23:59:59.000Z
We discuss the shear viscosity of the quark matter by using the Kubo-Mori formula. It is found that the shear viscosity is expressed in terms of the quark spectral function. If the spectral function is approximated by a modified Bright-Wigner type, the viscosity decreases as the width of the spectral function increases. We also discuss dependence of the shear viscosity on the temperature and the density.
None
2013-07-22T23:59:59.000Z
The Interdisciplinary Consortium for Research and Educational Access in Science and Engineering (INCREASE), assists minority-serving institutions in gaining access to world-class research facilities.
Apparatus and method for measuring viscosity
Murphy, R.J. Jr.
1986-02-25T23:59:59.000Z
The present invention is directed to an apparatus and method for measuring the viscosity of a fluid. This apparatus and method is particularly useful for the measurement of the viscosity of a liquid in a harsh environment characterized by high temperature and the presence of corrosive or deleterious gases and vapors which adversely affect conventional ball or roller bearings. The apparatus and method of the present invention employ one or more flexural or torsional bearings to suspend a bob capable of limited angular motion within a rotatable sleeve suspended from a stationary frame. 7 figs.
Apparatus and method for measuring viscosity
Murphy, Jr., Robert J. (Bellaire, TX)
1986-01-01T23:59:59.000Z
The present invention is directed to an apparatus and method for measuring the viscosity of a fluid. This apparatus and method is particularly useful for the measurement of the viscosity of a liquid in a harsh environment characterized by high temperature and the presence of corrosive or deleterious gases and vapors which adversely affect conventional ball or roller bearings. The apparatus and method of the present invention employ one or more flexural or torsional bearings to suspend a bob capable of limited angular motion within a rotatable sleeve suspended from a stationary frame.
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
Multipurpose Acoustic Sensor for Downhole Fluid Monitoring
Broader source: Energy.gov [DOE]
Novel sensor design based on acoustics. Determine in real-timeand in a single sensor packagemultiple parameters: temperature, pressure, fluid flow; and fluid properties, such as density, viscosity, fluid composition.
Experimental Investigation on High-pressure, High-temperature Viscosity of Gas Mixtures
Davani, Ehsan
2012-02-14T23:59:59.000Z
Modeling the performance of high-pressure, high-temperature (HPHT) natural gas reservoirs requires the understanding of gas behavior at such conditions. In particular, gas viscosity is an important fluid property that directly affects fluid flow...
Experimental Investigation on High-pressure, High-temperature Viscosity of Gas Mixtures
Davani, Ehsan
2012-02-14T23:59:59.000Z
Modeling the performance of high-pressure, high-temperature (HPHT) natural gas reservoirs requires the understanding of gas behavior at such conditions. In particular, gas viscosity is an important fluid property that directly affects fluid flow...
Energy-momentum tensor correlators and viscosity
Harvey B. Meyer
2008-09-30T23:59:59.000Z
Collective flow has been observed in heavy ion collisions, with a large anisotropic component, and ideal hydrodynamic calculations had significant successful in describing the distribution of produced particles at the RHIC experiments. In order to account for this near ideal fluid behavior, the shear and bulk viscosity of the quark gluon plasma (QGP) must be computed from first principles in a regime where the QGP is not weakly coupled. In this talk I describe recent progress in computing energy-momentum tensor correlators on the lattice from which the viscosities can be extracted via Kubo formulas. I also show how to cumulate information from several channels, including at non-vanishing spatial momentum, in order to best constrain the viscosities. These methods should soon yield predictions at the higher temperatures that will be explored at the LHC experiments.
Viscosity and Riemann solutions On the Influence of Viscosity on
Canic, Suncica
Viscosity and Riemann solutions On the Influence of Viscosity on Riemann Solutions SunĹ¸cica Ĺ¸ Cani and uniqueness of Riemann solutions are affected by the precise form of viscosity which is used to select shock on viscosity and distinguish between Lax shock waves with and without a profile. These bifurcations
Shear viscosity of hadronic gas mixtures
K. Itakura; O. Morimatsu; H. Otomo
2008-05-12T23:59:59.000Z
We investigate the effects of baryon chemical potential \\mu on the shear viscosity coefficient \\eta and the viscosity to entropy density ratio \\eta/s of a pion-nucleon gas mixture. We find that \\eta is an increasing function of T and \\mu, while the ratio \\eta/s turns to a decreasing function in a wide region of T-\\mu plane. In the kinematical region we studied, the smallest value of \\eta/s is about 0.3.
EXPERIMENTAL AND THEORETICAL DETERMINATION OF HEAVY OIL VISCOSITY...
Office of Scientific and Technical Information (OSTI)
of high viscosity oil produced by steam methods is increasing annually throughout the world 3 . Modern reservoir engineering practices require accurate information of...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
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Bulk viscosity in a cold CFL superfluid
Cristina Manuel; Felipe Llanes-Estrada
2007-07-18T23:59:59.000Z
We compute one of the bulk viscosity coefficients of cold CFL quark matter in the temperature regime where the contribution of mesons, quarks and gluons to transport phenomena is Boltzmann suppressed. In that regime dissipation occurs due to collisions of superfluid phonons, the Goldstone modes associated to the spontaneous breaking of baryon symmetry. We first review the hydrodynamics of relativistic superfluids, and remind that there are at least three bulk viscosity coefficients in these systems. We then compute the bulk viscosity coefficient associated to the normal fluid component of the superfluid. In our analysis we use Son's effective field theory for the superfluid phonon, amended to include scale breaking effects proportional to the square of the strange quark mass m_s. We compute the bulk viscosity at leading order in the scale breaking parameter, and find that it is dominated by collinear splitting and joining processes. The resulting transport coefficient is zeta=0.011 m_s^4/T, growing at low temperature T until the phonon fluid description stops making sense. Our results are relevant to study the rotational properties of a compact star formed by CFL quark matter.
Viscosity-Induced Crossing of the Phantom Barrier
Brevik, Iver
2015-01-01T23:59:59.000Z
We show explicitly, by using astrophysical data plus reasonable assumptions for the bulk viscosity in the cosmic fluid, how the magnitude of this viscosity may be high enough to drive the fluid from its position in the quintessence region at present time $t=0$ across the barrier $w=-1$ into the phantom region in the late universe. The phantom barrier is accordingly not a sharp mathematical divide, but rather a fuzzy concept. We also calculate the limiting forms of various thermodynamical quantities, including the rate of entropy production, for a dark energy fluid near the future Big Rip singularity.
Full Life Wind Turbine Gearbox Lubricating Fluids
Lutz, Glenn A.; Jungk, Manfred; Bryant, Jonathan J.; Lauer, Rebecca S.; Chobot, Anthony; Mayer, Tyler; Palmer, Shane; Kauffman, Robert E.
2012-02-28T23:59:59.000Z
Industrial gear box lubricants typically are hydrocarbon based mineral oils with considerable amounts of additives to overcome the lack of base fluid properties like wear protection, oxidation stability, load carrying capacity, low temperature solidification and drop of viscosity at higher temperatures. For today's wind turbine gearboxes, the requirements are more severe and synthetic hydrocarbon oils are used to improve on this, but all such hydrocarbon based lubricants require significant amounts of Extreme Pressure (EP) additives to meet performance requirements. Perfluoropolyether (PFPE) fluids provide load carrying capacity as an inherent property. During the course of the project with the main tasks of 'Establish a Benchmark', 'Lubricant Evaluation', 'Full Scale Gearbox Trial' and 'Economic Evaluation', the PAO Reference oil exhibited significant changes after laboratory gear testing, in service operation in the field and full scale gearbox trial. Four hydrocarbon base oils were selected for comparison in the benchmarking exercise and showed variation with respect to meeting the requirements for the laboratory micro-pitting tests, while the PFPE fluid exceeded the requirements even with the material taken after the full scale gear box trial. This is remarkable for a lubricant without EP additives. Laboratory bearing tests performed on the PFPE fluids before and after the full scale gear box trial showed the results met requirements for the industry standard. The PFPE fluid successfully completed the full scale gear box test program which included baseline and progressive staged load testing. The evaluation of gears showed no micro-pitting or objectionable wear. By the final stage, lubricant film thickness had been reduced to just 21% of its original value, this was by design and resulted in a lambda ratio of well below 1. This test design scenario of a low lambda ratio is a very undesirable lubrication condition for real world but creates the ability to test the lubricating fluids performance under the most extreme conditions. The PAO Reference oil also passed its testing without any noticeable deterioration of the gear surface. However the PAO Reference oil was replaced midway through the progressive loading, as the lubricant was burned in an attempt to raise the sump temperature to the same levels as for the PFPE. Both materials experienced a decrease of viscosity during their respective run times. The viscosity index decreased for the PAO there while there was a slight increase for the PFPE. FZG laboratory gear tests and measurements of the drive motor's current during the full scale gear box trial were made to characterize the relative efficiency between the PFPE fluid and the PAO Reference oil. In the FZG laboratory efficiency test, the PFPE fluids show much higher churning losses due to their higher viscosity and density. The analysis seems to show that the efficiency correlates better to dynamic viscosity than any other of the measured metrics such as film thickness. In load stages where the load, speed and temperature are similar, the PFPE fluid has a greater film thickness and theoretical gear protection, but requires a larger current for the drive motor than the PAO. However in load stages where the film thickness is the same, the PFPE fluid's reduced dynamic viscosity gives it a slight efficiency advantage relative to the PAO reference oil. Ultimately, many factors such as temperature, rotational speed, and fluid viscosity combine in a complex fashion to influence the results. However, the PFPE's much lower change of viscosity with respect to temperature, allows variations in designing an optimum viscosity to balance efficiency versus gear protection. Economic analysis was done using Cost of Energy calculations. The results vary from 5.3% for a 'Likely Case' to 16.8% for a 'Best Case' scenario as potential cost improvement by using PFPE as the gearbox lubricating fluid. It is important to note the largest portion of savings comes in Levelized Replacement Cost, which is dictated by the assumption on gearb
Viscosity of aqueous and cyanate ester suspensions containing alumina nanoparticles
Lawler, Katherine
2009-08-05T23:59:59.000Z
The viscosities of both aqueous and cyanate ester monomer (BECy) based suspensions of alumina nanoparticle were studied. The applications for these suspensions are different: aqueous suspensions of alumina nanoparticles are used in the production of technical ceramics made by slip casting or tape casting, and the BECy based suspensions are being developed for use in an injection-type composite repair resin. In the case of aqueous suspensions, it is advantageous to achieve a high solids content with low viscosity in order to produce a high quality product. The addition of a dispersant is useful so that higher solids content suspensions can be used with lower viscosities. For BECy suspensions, the addition of nanoparticles to the BECy resin is expected to enhance the mechanical properties of the cured composite. The addition of saccharides to aqueous suspensions leads to viscosity reduction. Through DSC measurements it was found that the saccharide molecules formed a solution with water and this resulted in lowering the melting temperature of the free water according to classic freezing point depression. Saccharides also lowered the melting temperature of the bound water, but this followed a different rule. The shear thinning and melting behaviors of the suspensions were used to develop a model based on fractal-type agglomeration. It is believed that the structure of the particle flocs in these suspensions changes with the addition of saccharides which leads to the resultant viscosity decrease. The viscosity of the BECy suspensions increased with solids content, and the viscosity increase was greater than predicted by the classical Einstein equation for dilute suspensions. Instead, the Mooney equation fits the viscosity behavior well from 0-20 vol% solids. The viscosity reduction achieved at high particle loadings by the addition of benzoic acid was also investigated by NMR. It appears that the benzoic acid interacts with the surface of the alumina particle which may be the cause of the viscosity reduction. The flow behavior of alumina particles in water and BECy is markedly different. Aqueous alumina suspensions are shear thinning at all alumina loadings and capable of 50 vol% loading before losing fluidity whereas BECy/alumina suspensions show Newtonian behavior up to 5 vol%, and above 5 vol% show shear thinning at all shear rates. Highly loaded suspensions (i.e. 20vol% alumina) exhibit shear thinning at low and moderate shear rates and shear thickening at higher shear rates. The maximum particle loading for a fluid suspension, in this case, appears to be about 20 vol%. The difference in the viscosity of these suspensions must be related to the solvent-particle interactions for each system. The reason is not exactly known, but there are some notable differences between BECy and water. Water molecules are {approx}0.28 nm in length and highly hydrogen bonded with a low viscosity (1 mPa's) whereas in the cyanate ester (BECy) system, the solvent molecule is about 1.2 nm, in the largest dimension, with surfaces of varied charge distribution throughout the molecule. The viscosity of the monomer is also reasonably low for organic polymer precursor, about 7 mPa's. Nanoparticles in water tend to agglomerate and form flocs which are broken with the shear force applied during viscosity measurement. The particle-particle interaction is very important in this system. In BECy, the particles appear to be well dispersed and not as interactive. The solvent-particle interaction appears to be most important. It is not known exactly how the alumina particles interact with the monomer, but NMR suggests hydrogen bonding. These hydrogen bonds between the particle and monomer could very well affect the viscosity. A conclusion that can be reached in this work is that the presence of hydroxyl groups on the surface of the alumina particles is significant and seems to affect the interactions between other particles and the solvent. Thus, the hydrogen bonding between particles, particle/additive and/or particle/solvent dictates the behavior of nanos
Comment on "Accelerating cosmological expansion from shear and bulk viscosity"
Giovannini, Massimo
2015-01-01T23:59:59.000Z
In a recent Letter [Phys. Rev. Lett. 114 091301 (2105)] the cause of the acceleration of the present Universe has been identified with the shear viscosity of an imperfect relativistic fluid even in the absence of any bulk viscous contribution. The gist of this comment is that the shear viscosity, if anything, can only lead to an accelerated expansion over sufficiently small scales well inside the Hubble radius.
Fayer, Michael D.
Viscosity Dependence of the Rotational Reorientation of Rhodamine B in Mono- and Polyalcohols-Stokes-Einstein (DSE) theorywas shown to extend to much higher viscosities than previously reported. Detailed of radius R and hydrodynamic volume V rotating in a fluid continuum of macroscopic viscosity q and relates
The nucleon thermal width due to pion-baryon loops and its contribution in Shear viscosity
Sabyasachi Ghosh
2015-03-24T23:59:59.000Z
In the real-time thermal field theory, the standard expression of shear viscosity for the nucleonic constituents is derived from the two point function of nucleonic viscous stress tensors at finite temperature and density. The finite thermal width or Landau damping is traditionally included in the nucleon propagators. This thermal width is calculated from the in-medium self-energy of nucleon for different possible pion-baryon loops. The dynamical part of nucleon-pion-baryon interactions are taken care by the effective Lagrangian densities of standard hadronic model. The shear viscosity to entropy density ratio of nucleonic component decreases with the temperature and increases with the nucleon chemical potential. However, adding the contribution of pionic component, total viscosity to entropy density ratio also reduces with the nucleon chemical potential when the mixing effect between pion and nucleon components in the mixed gas is considered. Within the hadronic domain, viscosity to entropy density ratio of the nuclear matter is gradually reducing as temperature and nucleon chemical potential are growing up and therefore the nuclear matter is approaching toward the (nearly) perfect fluid nature.
Polyfunctional dispersants for controlling viscosity of phyllosilicates
Chaiko, David J.
2006-07-25T23:59:59.000Z
This invention provides phyllosilicates and polyfunctional dispersants which can be manipulated to selectively control the viscosity of phyllosilicate slurries. The polyfunctional dispersants used in the present invention, which include at least three functional groups, increase the dispersion and exfoliation of phyllosilicates in polymers and, when used in conjunction with phyllosilicate slurries, significantly reduce the viscosity of slurries having high concentrations of phyllosilicates. The functional groups of the polyfunctional dispersants are capable of associating with multivalent metal cations and low molecular weight organic polymers, which can be manipulated to substantially increase or decrease the viscosity of the slurry in a concentration dependent manner. The polyfunctional dispersants of the present invention can also impart desirable properties on the phyllosilicate dispersions including corrosion inhibition and enhanced exfoliation of the phyllosilicate platelets.
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.
N J Watson; R K Johal; Y Reinwald; L J White; A M Ghaemmaghami; S P Morgan; F R A J Rose; M J W Povey; N G Parker
2013-02-18T23:59:59.000Z
We expose thick polymer foam tissue scaffolds to high power ultrasound and study its effect on the openness of the pore architecture and fluid transport through the scaffold. Our analysis is supported by measurements of fluid uptake during insonification and imaging of the scaffold microstructure via x-ray computed tomography, scanning electron microscopy and acoustic microscopy. The ultrasonic treatment is found to increase the mean pore size by over 10%. More striking is the improvement in fluid uptake: for scaffolds with only 40% water uptake via standard immersion techniques, we can routinely achieve full saturation of the scaffold over approximately one hour of exposure. These desirable modifications occur with no loss of scaffold integrity and negligible mass loss, and are optimized when the ultrasound treatment is coupled to a pre-wetting stage with ethanol. Our findings suggest that high power ultrasound is a highly targetted and efficient means to promote pore interconnectivity and fluid transport in thick foam tissue scaffolds.
Viscosity near phase transitions
Antonio Dobado; Felipe J. Llanes-Estrada; Juan M. Torres-Rincon
2010-09-30T23:59:59.000Z
Probably the most enticing observation in theoretical physics during the last decade was the discovery of the great amount of consequences obtained from the AdS/CFT conjecture put forward by Maldacena. In this work we review how this correspondence can be used to address hydrodynamic properties such as the viscosity of some strongly interacting systems. We also employ the Boltzmann equation for those systems closer to low-energy QCD, and argue that this kind of transport coefficients can be related to phase transitions, in particular the QGP/hadronic phase transition studied in heavy ion collisions.
Bulk Viscosity and Particle Creation in the Inflationary Cosmology
Mehdi Eshaghi; Nematollah Riazi; Ahmad Kiasatpour
2015-04-29T23:59:59.000Z
We study particle creation in the presence of bulk viscosity of cosmic fluid in the early universe within the framework of open thermodynamical systems. Since the first-order theory of non-equilibrium thermodynamics is non-causal and unstable, we try to solve the bulk viscosity equation of the cosmic fluid with particle creation through the full causal theory. By adopting an appropriate function for particle creation rate of "Creation of Cold Dark Matter" model, we obtain analytical solutions which do not suffer from the initial singularity and are in agreement with equivalent solutions of Lambda-CDM model. We constrain the free parameter of particle creation in our model based on recent Planck data. It is also found that the inflationary solution is driven by bulk viscosity with or without particle creation.
Bulk Viscosity and Particle Creation in the Inflationary Cosmology
Eshaghi, Mehdi; Kiasatpour, Ahmad
2015-01-01T23:59:59.000Z
We study particle creation in the presence of bulk viscosity of cosmic fluid in the early universe within the framework of open thermodynamical systems. Since the first-order theory of non-equilibrium thermodynamics is non-causal and unstable, we try to solve the bulk viscosity equation of the cosmic fluid with particle creation through the full causal theory. By adopting an appropriate function for particle creation rate of "Creation of Cold Dark Matter" model, we obtain analytical solutions which do not suffer from the initial singularity and are in agreement with equivalent solutions of Lambda-CDM model. We constrain the free parameter of particle creation in our model based on recent Planck data. It is also found that the inflationary solution is driven by bulk viscosity with or without particle creation.
Accelerating cosmological expansion from shear and bulk viscosity
Stefan Floerchinger; Nikolaos Tetradis; Urs Achim Wiedemann
2015-03-10T23:59:59.000Z
The dissipation of energy from local velocity perturbations in the cosmological fluid affects the time evolution of spatially averaged fluid dynamic fields and the cosmological solution of Einstein's field equations. We show how this backreaction effect depends on shear and bulk viscosity and other material properties of the dark sector, as well as the spectrum of perturbations. If sufficiently large, this effect could account for the acceleration of the cosmological expansion.
Optical fiber-based fluorescent viscosity sensor Mark A. Haidekker and Walter J. Akers
Theodorakis, Emmanuel
Optical fiber-based fluorescent viscosity sensor Mark A. Haidekker and Walter J. Akers Department to molecular rotors in solution. An optical fiber-based fluorescent vis- cosity sensor may be used in real, we sought to develop an optical fiber-based sensor that could re- port changes in fluid viscosity
A New Reference Correlation for the Viscosity of Methanol Hong Wei Xiang,a...
Magee, Joseph W.
A New Reference Correlation for the Viscosity of Methanol Hong Wei Xiang,a... Arno Laesecke for the viscosity of methanol is presented that is valid over the entire fluid region, including vapor, liquid coefficient is developed from experimental data and applied to methanol. The high-density contribution
Gas Viscosity at High Pressure and High Temperature
Ling, Kegang
2012-02-14T23:59:59.000Z
Gas viscosity is one of the gas properties that is vital to petroleum engineering. Its role in the oil and gas production and transportation is indicated by its contribution in the resistance to the flow of a fluid both in porous media and pipes...
THERMOPHYSICAL PROPERTIES OF NANOPARTICLE-ENHANCED IONIC LIQUIDS HEAT TRANSFER FLUIDS
Fox, E.
2013-04-15T23:59:59.000Z
An experimental investigation was completed on nanoparticle enhanced ionic liquid heat transfer fluids as an alternative to conventional organic based heat transfer fluids (HTFs). These nanoparticle-based HTFs have the potential to deliver higher thermal conductivity than the base fluid without a significant increase in viscosity at elevated temperatures. The effect of nanoparticle morphology and chemistry on thermophysical properties was examined. Whisker shaped nanomaterials were found to have the largest thermal conductivity temperature dependence and were also less likely to agglomerate in the base fluid than spherical shaped nanomaterials.
Shear viscosity of nuclear matter
Jun Xu
2013-02-01T23:59:59.000Z
In this talk I report my recent study on the shear viscosity of neutron-rich nuclear matter from a relaxation time approach. An isospin- and momentum-dependent interaction is used in the study. Effects of density, temperature, and isospin asymmetry of nuclear matter on its shear viscosity have been discussed. Similar to the symmetry energy, the symmetry shear viscosity is defined and its density and temperature dependence are studied.
V. Folomeev; V. Gurovich
2007-10-15T23:59:59.000Z
The unified dark energy and dark matter model within the framework of a model of a continuous medium with bulk viscosity (dark fluid) is considered. It is supposed that the bulk viscosity coefficient is an arbitrary function of the Hubble parameter. The choice of this function is carried out under the requirement to satisfy the observational data from recombination ($z\\approx 1000$) till present time.
Saturation of elliptic flow and shear viscosity
A. K. Chaudhuri
2007-10-08T23:59:59.000Z
Effect of shear viscosity on elliptic flow is studied in causal dissipative hydrodynamics in 2+1 dimensions. Elliptic flow is reduced in viscous dynamics. Causal evolution of minimally viscous fluid ($\\eta/s$=0.08), can explain the PHENIX data on elliptic flow in 16-23% Au+Au collisions up to $p_T\\approx$3.6 GeV. In contrast, ideal hydrodynamics, can explain the same data only up to $p_T\\approx$1.5 GeV. $p_T$ spectra of identified particles are also better explained in minimally viscous fluid than in ideal dynamics. However, saturation of elliptic flow at large $p_T$ is not reproduced.
Shear viscosity and shear thinning in two-dimensional Yukawa , J. Goree2
Goree, John
Shear viscosity and shear thinning in two-dimensional Yukawa liquids Z. Donk´o1 , J. Goree2 , P using two different nonequi- librium molecular dynamics simulation methods. Shear viscosity values.e., the viscosity diminishes with increasing shear rate. It is expected that two-dimensional dusty plasmas
Viscosity-Dependent Protein Dynamics Ilya J. Finkelstein, Aaron M. Massari, and M. D. Fayer
Fayer, Michael D.
Viscosity-Dependent Protein Dynamics Ilya J. Finkelstein, Aaron M. Massari, and M. D. Fayer viscosity at room temperature in four heme proteins: hemoglobin, myoglobin, a myoglobin mutant replaced by an alanine (M61A). Fructose is added to increase the viscosity of the aqueous protein solutions
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...
Fluid&ParticulateSystems 424514/2010
Zevenhoven, Ron
cake solids mass/m2, w 3. Ruth equation using dw = (1-)solid dx fluidL p Ku solidK )1( 1 resistance, , with cake porosity : velocity, u layer thickness, L pressure drop, p dynamic viscosity, fluid Finland februari 2014 Unit w: kg/m2 Fluid&ParticulateSystems 424514/2010 Fluid&ParticulateSystems ĹA424514
Transport coefficients of soft sphere fluids at high densities
Yu. D. Fomin; V. V. Brazhkin; V. N. Ryzhov
2010-03-19T23:59:59.000Z
Molecular dynamics computer simulation has been used to compute the self-diffusion coefficient, and shear viscosity of soft-sphere fluids, in which the particles interact through the soft-sphere or inverse power pair potential. The calculations have been made along the melting line in a wide range of pressures and temperatures. The validity of scaling relations for thermodynamic parameters and kinetic coefficients was checked. It was shown that the Stokes-Einstein relationship is obeyed if the Barker diameter is used as a characteristic length scale. It was also shown that the viscosity is non-monotonic along the isochores as predicted by Ya. Rosenfeld. It was shown that the viscosity is strongly growing along the melting line, however, this increase does not stimulate the glass transition because the relaxation time is decreasing.
Effective viscoelastic medium from fractured fluid-saturated ...
2013-02-27T23:59:59.000Z
... to Comput. Methods Appl. Mech. Engrg. 27 February 2013 ... where ? is the fluid viscosity and k the absolute permeability. S is known as the structure or ...
Anomalous - viscosity current drive
Stix, Thomas H. (Princeton, NJ); Ono, Masayuki (Princeton Junction, NJ)
1988-01-01T23:59:59.000Z
An apparatus and method for maintaining a steady-state current in a toroidal magnetically confined plasma. An electric current is generated in an edge region at or near the outermost good magnetic surface of the toroidal plasma. The edge current is generated in a direction parallel to the flow of current in the main plasma and such that its current density is greater than the average density of the main plasma current. The current flow in the edge region is maintained in a direction parallel to the main current for a period of one or two of its characteristic decay times. Current from the edge region will penetrate radially into the plasma and augment the main plasma current through the mechanism of anomalous viscosity. In another aspect of the invention, current flow driven between a cathode and an anode is used to establish a start-up plasma current. The plasma-current channel is magnetically detached from the electrodes, leaving a plasma magnetically insulated from contact with any material obstructions including the cathode and anode.
Bulk Viscosity, Decaying Dark Matter, and the Cosmic Acceleration
James R. Wilson; Grant J. Mathews; George M. Fuller
2006-09-25T23:59:59.000Z
We discuss a cosmology in which cold dark-matter particles decay into relativistic particles. We argue that such decays could lead naturally to a bulk viscosity in the cosmic fluid. For decay lifetimes comparable to the present hubble age, this bulk viscosity enters the cosmic energy equation as an effective negative pressure. We investigate whether this negative pressure is of sufficient magnitude to account fo the observed cosmic acceleration. We show that a single decaying species in a flat, dark-matter dominated cosmology without a cosmological constant cannot reproduce the observed magnitude-redshift relation from Type Ia supernovae. However, a delayed bulk viscosity, possibly due to a cascade of decaying particles may be able to account for a significant fraction of the apparent cosmic acceleration. Possible candidate nonrelativistic particles for this scenario include sterile neutrinos or gauge-mediated decaying supersymmetric particles.
Tembely, M.; Vadillo, D.; Mackley, M.R.; Soucemarianadin, A.
2012-01-23T23:59:59.000Z
Research (LEGI), UMR 5519, University Joseph Fourier, Grenoble, BP 53, 38041 Grenoble Cedex, France D. Vadillo and M. R. Mackley Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge CB2 3RA, United Kingdom A... al. (2002); Crassous et al. (2005); Kirschen- mann (2003)] to obtain linear viscoelastic data of the fluids under test, and a specially designed filament stretching apparatus (Cambridge Trimaster MkII) was used to achieve controlled stretching...
Vanishing Viscosity Method for Transonic Flow
Gui-Qiang Chen; Marshall Slemrod; Dehua Wang
2006-10-07T23:59:59.000Z
A vanishing viscosity method is formulated for two-dimensional transonic steady irrotational compressible fluid flows with adiabatic constant $\\gamma\\in [1,3)$. This formulation allows a family of invariant regions in the phase plane for the corresponding viscous problem, which implies an upper bound uniformly away from cavitation for the viscous approximate velocity fields. Mathematical entropy pairs are constructed through the Loewner-Morawetz relation by entropy generators governed by a generalized Tricomi equation of mixed elliptic-hyperbolic type, and the corresponding entropy dissipation measures are analyzed so that the viscous approximate solutions satisfy the compensated compactness framework. Then the method of compensated compactness is applied to show that a sequence of solutions to the artificial viscous problem, staying uniformly away from stagnation, converges to an entropy solution of the inviscid transonic flow problem.
Jishan Fan; Fucai Li; Gen Nakamura
2014-07-24T23:59:59.000Z
In this paper we establish some regularity criteria for the 3D Boussinesq system with the temperature-dependent viscosity and thermal diffusivity. We also obtain some uniform estimates for the corresponding 2D case when the fluid viscosity coefficient is a positive constant.
Reversible shear thickening at low shear rates of electrorheological fluids under electric fields
Yu Tian; Minliang Zhang; Jile Jiang; Noshir Pesika; Hongbo Zeng; Jacob Israelachvili; Yonggang Meng; Shizhu Wen
2010-08-24T23:59:59.000Z
Shear thickening is a phenomenon of significant viscosity increase of colloidal suspensions. While electrorheological (ER) fluids can be turned into a solid-like material by applying an electric field, their shear strength is widely represented by the attractive electrostatic interaction between ER particles. By shearing ER fluids between two concentric cylinders, we show a reversible shear thickening of ER fluids above a low critical shear rate (electric field strength (>100 V/mm), which could be characterized by a modified Mason number. Shear thickening and electrostatic particle interaction-induced inter-particle friction forces is considered to be the real origin of the high shear strength of ER fluids, while the applied electric field controls the extent of shear thickening. The electric field-controlled reversible shear thickening has implications for high-performance ER/magnetorheological (MR) fluid design, clutch fluids with high friction forces triggered by applying local electric field, other field-responsive materials and intelligent systems.
Vertical two-phase flow regimes and pressure gradients: Effect of viscosity
Da Hlaing, Nan; Sirivat, Anuvat; Siemanond, Kitipat [The Petroleum and Petrochemical College, Chulalongkorn University, Soi Chula 12, Phayathai Road, Pathumwan, Bangkok 10330 (Thailand); Wilkes, James O. [Department of Chemical Engineering, The University of Michigan, Ann Arbor, MI 48109-2136 (United States)
2007-05-15T23:59:59.000Z
The effect of liquid viscosity on the flow regimes and the corresponding pressure gradients along the vertical two-phase flow was investigated. Experiment was carried out in a vertical transparent tube of 0.019 m in diameter and 3 m in length and the pressure gradients were measured by a U-tube manometer. Water and a 50 vol.% glycerol solution were used as the working fluids whose kinematic viscosities were 0.85 x 10{sup -6} and 4.0 x 10{sup -6} m{sup 2}/s, respectively. In our air-liquid annular two-phase flow, the liquid film of various thicknesses flowed adjacent to the wall and the gas phase flowed at the center of the tube. The superficial air velocity, j{sub air}, was varied between 0.0021 and 58.7 m/s and the superficial liquid velocity, j{sub liquid}, was varied between 0 and 0.1053 m/s. In the bubble, the slug and the slug-churn flow regimes, the pressure gradients decreased with increasing Reynolds number. But in the annular and the mist flow regimes, pressure gradients increased with increasing Reynolds number. Finally, the experimentally measured pressure gradient values were compared and are in good agreement with the theoretical values. (author)
Viscosity in X-ray clusters: Braginskii over 5
A. Gruzinov
2006-11-07T23:59:59.000Z
We argue that it is currently impossible to simulate X-ray clusters using correct equations, because even the MHD description is not applicable. But since fluid simulations actually reproduce observations quite well, one may try to improve the fluid codes by including molecular transport of heat and momentum. We calculate the effective molecular viscosity for the simplest model of magnetic field and obtain 1/5 of the Braginskii value, similar to 1/3 of Spitzer for the heat conduction. This is large enough to noticeably damp the X-ray cluster turbulence.
Rodriguez, Jose Ramon
2001-01-01T23:59:59.000Z
This experimental study investigates the effects of inclination angle and fluid viscosity on zero net liquid flow (ZNLF). Predicting liquid holdup under ZNLF conditions is necessary in several types of petroleum industry operations. These include...
High Temperature, high pressure equation of state density correlations and viscosity correlations
Tapriyal, D.; Enick, R.; McHugh, M.; Gamwo, I.; Morreale, B.
2012-07-31T23:59:59.000Z
Global increase in oil demand and depleting reserves has derived a need to find new oil resources. To find these untapped reservoirs, oil companies are exploring various remote and harsh locations such as deep waters in Gulf of Mexico, remote arctic regions, unexplored deep deserts, etc. Further, the depth of new oil/gas wells being drilled has increased considerably to tap these new resources. With the increase in the well depth, the bottomhole temperature and pressure are also increasing to extreme values (i.e. up to 500 F and 35,000 psi). The density and viscosity of natural gas and crude oil at reservoir conditions are critical fundamental properties required for accurate assessment of the amount of recoverable petroleum within a reservoir and the modeling of the flow of these fluids within the porous media. These properties are also used to design appropriate drilling and production equipment such as blow out preventers, risers, etc. With the present state of art, there is no accurate database for these fluid properties at extreme conditions. As we have begun to expand this experimental database it has become apparent that there are neither equations of state for density or transport models for viscosity that can be used to predict these fundamental properties of multi-component hydrocarbon mixtures over a wide range of temperature and pressure. Presently, oil companies are using correlations based on lower temperature and pressure databases that exhibit an unsatisfactory predictive capability at extreme conditions (e.g. as great as {+-} 50%). From the perspective of these oil companies that are committed to safely producing these resources, accurately predicting flow rates, and assuring the integrity of the flow, the absence of an extensive experimental database at extreme conditions and models capable of predicting these properties over an extremely wide range of temperature and pressure (including extreme conditions) makes their task even more daunting.
Shear Viscosity of Quark Matter
W. M. Alberico; S. Chiacchiera; H. Hansen; A. Molinari; M. Nardi
2007-07-30T23:59:59.000Z
We consider the shear viscosity of a system of quarks and its ratio to the entropy density above the critical temperature for deconfinement. Both quantities are derived and computed for different modeling of the quark self-energy, also allowing for a temperature dependence of the effective mass and width. The behaviour of the viscosity and the entropy density is argued in terms of the strength of the coupling and of the main characteristics of the quark self-energy. A comparison with existing results is also discussed.
Bulk Viscosity of Interacting Hadrons
A. Wiranata; M. Prakash
2009-09-16T23:59:59.000Z
We show that first approximations to the bulk viscosity $\\eta_v$ are expressible in terms of factors that depend on the sound speed $v_s$, the enthalpy, and the interaction (elastic and inelastic) cross section. The explicit dependence of $\\eta_v$ on the factor $(\\frac 13 - v_s^2)$ is demonstrated in the Chapman-Enskog approximation as well as the variational and relaxation time approaches. The interesting feature of bulk viscosity is that the dominant contributions at a given temperature arise from particles which are neither extremely nonrelativistic nor extremely relativistic. Numerical results for a model binary mixture are reported.
Anomalous-viscosity current drive
Stix, T.H.; Ono, M.
1986-04-25T23:59:59.000Z
The present invention relates to a method and apparatus for maintaining a steady-state current for magnetically confining the plasma in a toroidal magnetic confinement device using anomalous viscosity current drive. A second aspect of this invention relates to an apparatus and method for the start-up of a magnetically confined toroidal plasma.
Bulk viscosity and deflationary universes
J. A. S. Lima; R. Portugal; I. Waga
2007-08-24T23:59:59.000Z
We analyze the conditions that make possible the description of entropy generation in the new inflationary model by means of a nearequilibrium process. We show that there are situations in which the bulk viscosity cannot describe particle production during the coherent field oscillations phase.
Fourier's Law for a Granular Fluid
James W. Dufty
2007-07-07T23:59:59.000Z
Newton' viscosity law for the momentum flux and Fourier's law for the heat flux define Navier-Stokes hydrodynamics for a simple, one component fluid. There is ample evidence that a hydrodynamic description applies as well to a mesoscopic granular fluid with the same form for Newton's viscosity law. However, theory predicts a qualitative difference for Fourier's law with an additional contribution from density gradients even at uniform temperature. The reasons for the absence of such terms for normal fluids are indicated, and a related microscopic explanation for their existence in granular fluids is presented.
"Nanotechnology Enabled Advanced Industrial Heat Transfer Fluids"
Dr. Ganesh Skandan; Dr. Amit Singhal; Mr. Kenneth Eberts; Mr. Damian Sobrevilla; Prof. Jerry Shan; Stephen Tse; Toby Rossmann
2008-06-12T23:59:59.000Z
ABSTRACT Nanotechnology Enabled Advanced industrial Heat Transfer Fluids” Improving the efficiency of Industrial Heat Exchangers offers a great opportunity to improve overall process efficiencies in diverse industries such as pharmaceutical, materials manufacturing and food processing. The higher efficiencies can come in part from improved heat transfer during both cooling and heating of the material being processed. Additionally, there is great interest in enhancing the performance and reducing the weight of heat exchangers used in automotives in order to increase fuel efficiency. The goal of the Phase I program was to develop nanoparticle containing heat transfer fluids (e.g., antifreeze, water, silicone and hydrocarbon-based oils) that are used in transportation and in the chemical industry for heating, cooling and recovering waste heat. Much work has been done to date at investigating the potential use of nanoparticle-enhanced thermal fluids to improve heat transfer in heat exchangers. In most cases the effect in a commercial heat transfer fluid has been marginal at best. In the Phase I work, we demonstrated that the thermal conductivity, and hence heat transfer, of a fluid containing nanoparticles can be dramatically increased when subjected to an external influence. The increase in thermal conductivity was significantly larger than what is predicted by commonly used thermal models for two-phase materials. Additionally, the surface of the nanoparticles was engineered so as to have a minimal influence on the viscosity of the fluid. As a result, a nanoparticle-laden fluid was successfully developed that can lead to enhanced heat transfer in both industrial and automotive heat exchangers
Shear viscosity of the quark matter
Masaharu Iwasaki; Hiromasa Ohnishi; Takahiko Fukutome
2007-05-14T23:59:59.000Z
We discuss shear viscosity of the quark matter by using Kubo formula. The shear viscosity is calculated in the framework of the quasi-particle RPA for the Nambu-Jona-Lasinio model. We obtain a formula that the shear viscosity is expressed by the quadratic form of the quark spectral function in the chiral symmetric phase. The magnitude of the shear viscosity is discussed assuming the Breit-Wigner type for the spectral function.
Optimization Online - AN ASYMPTOTIC VISCOSITY SELECTION ...
Boushra Abbas
2015-04-29T23:59:59.000Z
Apr 29, 2015 ... AN ASYMPTOTIC VISCOSITY SELECTION RESULT FOR THE REGULARIZED NEWTON DYNAMIC. Boushra Abbas(abbas.boushra ***at*** ...
Ocean viscosity and climate M. Jochum,1
Jochum, Markus
Ocean viscosity and climate M. Jochum,1 G. Danabasoglu,1 M. Holland,1 Y.-O. Kwon,1 and W. G. Large1] The impacts of parameterized lateral ocean viscosity on climate are explored using three 120-year integrations of a fully coupled climate model. Reducing viscosity leads to a generally improved ocean circulation
VISCOSITY IN ACCRETION DISKS PAUL J. WIITA
Wiita, Paul J.
VISCOSITY IN ACCRETION DISKS PAUL J. WIITA Department of Physics & Astronomy, Georgia State University Atlanta, Georgia, USA Abstract. Various proposals and prescriptions for the viscosity in accretion a solution to this difficult problem. 1. Introduction The nature of the viscosity within accretion disks
Effective Viscosity of Confined Hydrocarbons
I. M. Sivebaek; V. N. Samoilov; B. N. J. Persson
2012-01-24T23:59:59.000Z
We present molecular dynamics friction calculations for confined hydrocarbon films with molecular lengths from 20 to 1400 carbon atoms. We find that the logarithm of the effective viscosity \\mu eff for nanometer-thin films depends linearly on the logarithm of the shear rate: log(effective viscosity) = C - n log (shear rate), where n varies from 1 (solidlike friction) at very low temperatures to 0 (Newtonian liquid) at very high temperatures, following an inverse sigmoidal curve. Only the shortest chain molecules melt, whereas the longer ones only show a softening in the studied temperature interval 0 < T < 900 K. The results are important for the frictional properties of very thin (nanometer) films and to estimate their thermal durability.
Predicting human blood viscosity in silico
Fedosov, Dmitry A.; Pan, Wenxiao; Caswell, Bruce; Gompper, Gerhard; Karniadakis, George E.
2011-07-19T23:59:59.000Z
Cellular suspensions such as blood are a part of living organisms and their rheological and ?ow characteristics determine and affect majority of vital functions. The rheological and ?ow properties of cell suspensions are determined by collective dynamics of cells, their structure or arrangement, cell properties and interactions. We study these relations for blood in silico using a mesoscopic particle-based method and two different models (multi-scale/low-dimensional) of red blood cells. The models yield accurate quantitative predictions of the dependence of blood viscosity on shear rate and hematocrit. We explicitly model cell aggregation interactions and demonstrate the formation of reversible rouleaux structures resulting in a tremendous increase of blood viscosity at low shear rates and yield stress, in agreement with experiments. The non-Newtonian behavior of such cell suspensions (e.g., shear thinning, yield stress) is analyzed and related to the suspension’s microstructure, deformation and dynamics of single cells. We provide the ?rst quantitative estimates of normal stress differences and magnitude of aggregation forces in blood. Finally, the ?exibility of the cell models allows them to be employed for quantitative analysis of a much wider class of complex ?uids including cell, capsule, and vesicle suspensions.
Bulk Viscosity of a Gas of Massless Pions
Jiunn-Wei Chen; Juven Wang
2009-03-31T23:59:59.000Z
In the hadronic phase, the dominant configuration of QCD with two flavors of massless quarks is a gas of massless pions. We calculate the bulk viscosity (zeta) using the Boltzmann equation with the kinetic theory generalized to incorporate the trace anomaly. We find that the dimensionless ratio zeta/s, s being the entropy density, is monotonic increasing below T=120 MeV, where chiral perturbation theory is applicable. This, combined with previous results, shows that zeta/s reaches its maximum near the phase transition temperature Tc, while eta/s, eta being the shear viscosity, reaches its minimum near Tc in QCD with massless quarks.
Stress tensor and bulk viscosity in relativistic nuclear collisions
Fries, Rainer J.; Mueller, Berndt; Schaefer, Andreas.
2008-01-01T23:59:59.000Z
of longitudinal and transverse components of the pressure and the extent of dissipative entropy production in the one-dimensional, boost-invariant hydrodynamic model. We find that a bulk viscosity consistent with recent estimates from lattice QCD further slows...however, it does not significantly increase the entropy produced....
Viscosity in cosmological simulations of clusters of galaxies
M. Brüggen; M. Ruszkowski
2005-12-06T23:59:59.000Z
The physics of the intracluster medium, in particular the values for the thermal conductivity and the viscosity are largely unknown and subject to an ongoing debate. Here, we study the effect of viscosity on the thermal state of the intracluster medium using three-dimensional cosmological simulations of structure formation. It is shown that viscosity, provided it is not too far off from the unmagnetised Spitzer value, has a significant effect on cluster profiles. In particular, it aids in heating the cool cores of clusters. The central cooling time of the most massive clusters in our simulation is increased by more than an order of magnitude. In large clusters, viscous heating may help to establish an entropy floor and to prevent a cooling catastrophe.
Supercritical Fluid Extraction
Johnston, K. P.; Flarsheim, W. M.
1984-01-01T23:59:59.000Z
changes in the solvent density and thus its dissolving power. In comparison with conventional processes, SFE offers considerable flexibility for an extractive separation using the variables of pressure, temperature, choice of solvent, and additives... or vacuum processing stages. 5. While the density, and thus the solvent capacity, of a supercritical fluid is nearly comparable to that of a liquid, the lower viscosity and higher diffusivity provide advantages in transport rates. For example...
Falsification of dark energy by fluid mechanics
Carl H. Gibson
2012-03-23T23:59:59.000Z
The 2011 Nobel Prize in Physics was awarded for the discovery of accelerating supernovae dimness, suggesting a remarkable change in the expansion rate of the Universe from a decrease since the big bang to an increase, driven by anti-gravity forces of a mysterious dark energy material comprising 70% of the Universe mass-energy. Fluid mechanical considerations falsify both the accelerating expansion and dark energy concepts. Kinematic viscosity is neglected in current standard models of self-gravitational structure formation, which rely on cold dark matter CDM condensations and clusterings that are also falsified by fluid mechanics. Weakly collisional CDM particles do not condense but diffuse away. Photon viscosity predicts superclustervoid fragmentation early in the plasma epoch and protogalaxies at the end. At the plasma-gas transition, the plasma fragments into Earth-mass gas planets in trillion planet clumps (proto-globular-star-cluster PGCs). The hydrogen planets freeze to form the dark matter of galaxies and merge to form their stars. Dark energy is a systematic dimming error for Supernovae Ia caused by dark matter planets near hot white dwarf stars at the Chandrasekhar carbon limit. Evaporated planet atmospheres may or may not scatter light from the events depending on the line of sight.
Bulk viscosity-driven suppression of shear viscosity effects on the flow harmonics at RHIC
J. Noronha-Hostler; J. Noronha; F. Grassi
2014-06-19T23:59:59.000Z
The interplay between shear and bulk viscosities on the flow harmonics, $v_n$'s, at RHIC is investigated using the newly developed relativistic 2+1 hydrodynamical code v-USPhydro that includes bulk and shear viscosity effects both in the hydrodynamic evolution and also at freeze-out. While shear viscosity is known to attenuate the flow harmonics, we find that the inclusion of bulk viscosity decreases the shear viscosity-induced suppression of the flow harmonics bringing them closer to their values in ideal hydrodynamical calculations. Depending on the value of the bulk viscosity to entropy density ratio, $\\zeta/s$, in the quark-gluon plasma, the bulk viscosity-driven suppression of shear viscosity effects on the flow harmonics may require a re-evaluation of the previous estimates of the shear viscosity to entropy density ratio, $\\eta/s$, of the quark-gluon plasma previously extracted by comparing hydrodynamic calculations to heavy ion data.
Varying properties of in situ heat treatment of a tar sands formation based on assessed viscosities
Karanikas, John Michael; Vinegar, Harold J
2014-03-04T23:59:59.000Z
A method for treating a tar sands formation includes providing heat to at least part of a hydrocarbon layer in the formation from a plurality of heaters located in the formation. The heat is allowed to transfer from the heaters to at least a portion of the formation. A viscosity of one or more zones of the hydrocarbon layer is assessed. The heating rates in the zones are varied based on the assessed viscosities. The heating rate in a first zone of the formation is greater than the heating rate in a second zone of the formation if the viscosity in the first zone is greater than the viscosity in the second zone. Fluids are produced from the formation through the production wells.
Holographic Viscosity of Fundamental Matter
David Mateos; Robert C. Myers; Rowan M. Thomson
2006-10-16T23:59:59.000Z
A holographic dual of a finite-temperature SU(N_c) gauge theory with a small number of flavours N_f viscosity to entropy ratio in these theories saturates the conjectured universal bound eta/s >= 1/4\\pi. The contribution of the fundamental matter eta_fund is therefore enhanced at strong 't Hooft coupling lambda; for example, eta_fund ~ lambda N_c N_f T^3 in four dimensions. Other transport coefficients are analogously enhanced. These results hold with or without a baryon number chemical potential.
Effective viscosity of microswimmer suspensions
Salima Rafai; Levan Jibuti; Philippe Peyla
2010-01-26T23:59:59.000Z
The measurement of a quantitative and macroscopic parameter to estimate the global motility of a large population of swimming biological cells is a challenge Experiments on the rheology of active suspensions have been performed. Effective viscosity of sheared suspensions of live unicellular motile micro-algae (\\textit{Chlamydomonas Reinhardtii}) is far greater than for suspensions containing the same volume fraction of dead cells and suspensions show shear thinning behaviour. We relate these macroscopic measurements to the orientation of individual swimming cells under flow and discuss our results in the light of several existing models.
Viscosity scaling of fingering instability in finite slices with Korteweg stress
Pramanik, Satyajit
2015-01-01T23:59:59.000Z
We perform linear stability analyses (LSA) and direct numerical simulations (DNS) to investigate the influence of the dynamic viscosity on viscous fingering (VF) instability in miscible slices. Selecting the characteristic scales appropriately the importance of the magnitude of the dynamic viscosity of individual fluids on VF in miscible slice has been shown in the context of the transient interfacial tension. Further, we have confirmed this result for immiscible fluids and manifest the similarities between VF in immiscible and miscible slices with transient interfacial tension. In a more general setting, the findings of this letter will be very useful for multiphase viscous flow, in which the momentum balance equation contains an additional stress term free from the dynamic viscosity.
Sweeping has no effect on renormalized turbulent viscosity
Mahendra K. Verma; Abhishek Kumar
2014-11-11T23:59:59.000Z
We employ renormalization group techniques (RG) to the Navier-Stokes equation in the presence of constant mean velocity field $\\mathbf U_0$, and show that the renormalized viscosity is independent of $\\mathbf U_0$. Thus we demonstrates that the renormalized parameter in Eulerian field theory is Galilean invariant, and it is unaffected by the "sweeping effect", contrary to the results of Kraichnan [Phys. Fluids {\\bf 7}, 1723 (1964)] on random Galilean invariance. Using direct numerical simulation, we show that the correlation functions for $\\mathbf U_0 =0$ and $\\mathbf U_0 \
Boal, David
viscosity . In Lecture 8, this viscosity appears in Stokes' Law for the drag force on a sphere of radius R moving at a speed v FDRAG = 6Rv. The larger , the larger the drag force, all other things being equal of which the boundary exerts drag on the fluid motion. This is similar to the frictional force between two
PHYSICAL REVIEW E 87, 013106 (2013) Longitudinal viscosity of two-dimensional Yukawa liquids
Goree, John
2013-01-01T23:59:59.000Z
is obtained for a two-dimensional (2D) liquid using a Green-Kubo method with a molecular dynamics simulation characterize energy dissipation in a fluid. Bulk viscosity is for energy dissipation due to compression, in contrast, is for energy dissipation due to a gradient in the flow velocity. In the latter case, the energy
Short-lived lattice quasiparticles for strongly interacting fluids
Mendoza, M
2015-01-01T23:59:59.000Z
It is shown that lattice kinetic theory based on short-lived quasiparticles proves very effective in simulating the complex dynamics of strongly interacting fluids (SIF). In particular, it is pointed out that the shear viscosity of lattice fluids is the sum of two contributions, one due to the usual interactions between particles (collision viscosity) and the other due to the interaction with the discrete lattice (propagation viscosity). Since the latter is {\\it negative}, the sum may turn out to be orders of magnitude smaller than each of the two contributions separately, thus providing a mechanism to access SIF regimes at ordinary values of the collisional viscosity. This concept, as applied to quantum superfluids in one-dimensional optical lattices, is shown to reproduce shear viscosities consistent with the AdS-CFT holographic bound on the viscosity/entropy ratio. This shows that lattice kinetic theory continues to hold for strongly coupled hydrodynamic regimes where continuum kinetic theory may no longer...
Gonzalez Zambrano, Alfredo Antonio
2002-01-01T23:59:59.000Z
Accurate prediction of gas condensate and crude oil fluid properties are critical elements in reservoir-engineering calculations. Dewpoint pressure of gas condensate reservoirs and oil viscosity of black oil systems are some of the important...
AN ASYMPTOTIC VISCOSITY SELECTION RESULT FOR THE ...
2015-04-29T23:59:59.000Z
Apr 29, 2015 ... viscosity selection properties for the regularized Newton dynamic governed by ?. Let us first recall some basic facts about this dynamical ...
Bulk viscosity in kaon condensed matter
Debarati Chatterjee; Debades Bandyopadhyay
2007-05-30T23:59:59.000Z
We investigate the effect of $K^-$ condensed matter on bulk viscosity and r-mode instability in neutron stars. The bulk viscosity coefficient due to the non-leptonic process $n \\rightleftharpoons p + K^-$ is studied here. In this connection, equations of state are constructed within the framework of relativistic field theoretical models where nucleon-nucleon and kaon-nucleon interactions are mediated by the exchange of scalar and vector mesons. We find that the bulk viscosity coefficient due to the non-leptonic weak process in the condensate is suppressed by several orders of magnitude. Consequently, kaon bulk viscosity may not damp the r-mode instability in neutron stars.
RMOTC to Test Oil Viscosity Reduction Technology
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
RMOTC to Test Oil Viscosity Reduction Technology The Rocky Mountain Oilfield Testing Center (RMOTC) announces that the "Teapot Dome" oil field in Wyoming is hosting a series of...
Heat Transfer in Complex Fluids
Mehrdad Massoudi
2012-01-01T23:59:59.000Z
Amongst the most important constitutive relations in Mechanics, when characterizing the behavior of complex materials, one can identify the stress tensor T, the heat flux vector q (related to heat conduction) and the radiant heating (related to the radiation term in the energy equation). Of course, the expression 'complex materials' is not new. In fact, at least since the publication of the paper by Rivlin & Ericksen (1955), who discussed fluids of complexity (Truesdell & Noll, 1992), to the recently published books (Deshpande et al., 2010), the term complex fluids refers in general to fluid-like materials whose response, namely the stress tensor, is 'non-linear' in some fashion. This non-linearity can manifest itself in variety of forms such as memory effects, yield stress, creep or relaxation, normal-stress differences, etc. The emphasis in this chapter, while focusing on the constitutive modeling of complex fluids, is on granular materials (such as coal) and non-linear fluids (such as coal-slurries). One of the main areas of interest in energy related processes, such as power plants, atomization, alternative fuels, etc., is the use of slurries, specifically coal-water or coal-oil slurries, as the primary fuel. Some studies indicate that the viscosity of coal-water mixtures depends not only on the volume fraction of solids, and the mean size and the size distribution of the coal, but also on the shear rate, since the slurry behaves as shear-rate dependent fluid. There are also studies which indicate that preheating the fuel results in better performance, and as a result of such heating, the viscosity changes. Constitutive modeling of these non-linear fluids, commonly referred to as non-Newtonian fluids, has received much attention. Most of the naturally occurring and synthetic fluids are non-linear fluids, for example, polymer melts, suspensions, blood, coal-water slurries, drilling fluids, mud, etc. It should be noted that sometimes these fluids show Newtonian (linear) behavior for a given range of parameters or geometries; there are many empirical or semi-empirical constitutive equations suggested for these fluids. There have also been many non-linear constitutive relations which have been derived based on the techniques of continuum mechanics. The non-linearities oftentimes appear due to higher gradient terms or time derivatives. When thermal and or chemical effects are also important, the (coupled) momentum and energy equations can give rise to a variety of interesting problems, such as instability, for example the phenomenon of double-diffusive convection in a fluid layer. In Conclusion, we have studied the flow of a compressible (density gradient type) non-linear fluid down an inclined plane, subject to radiation boundary condition. The heat transfer is also considered where a source term, similar to the Arrhenius type reaction, is included. The non-dimensional forms of the equations are solved numerically and the competing effects of conduction, dissipation, heat generation and radiation are discussed. It is observed that the velocity increases rapidly in the region near the inclined surface and is slower in the region near the free surface. Since R{sub 7} is a measure of the heat generation due to chemical reaction, when the reaction is frozen (R{sub 7}=0.0) the temperature distributions would depend only on R{sub 1}, and R{sub 2}, representing the effects of the pressure force developed in the material due to the distribution, R{sub 3} and R{sub 4} viscous dissipation, R{sub 5} the normal stress coefficient, R{sub 6} the measure of the emissivity of the particles to the thermal conductivity, etc. When the flow is not frozen (RP{sub 7} > 0) the temperature inside the flow domain is much higher than those at the inclined and free surfaces. As a result, heat is transferred away from the flow toward both the inclined surface and the free surface with a rate that increases as R{sub 7} increases. For a given temperature, an increase in {zeta} implies that the activation energy is smaller and thus, the reaction ra
Eiji Nakano
2007-03-21T23:59:59.000Z
Using chiral perturbation theory we investigate the QCD shear viscosity ($\\eta $) to entropy density ($s$) ratio below the deconfinement temperature ($\\sim 170$ MeV) with zero baryon number density. It is found that $\\eta /s$ of QCD is monotonically decreasing in temperature ($T$) and reaches 0.6 with estimated $\\sim 50%$ uncertainty at T=120 MeV. A naive extrapolation of the leading order result shows that $\\eta /s$ reaches the $1/4\\pi $ minimum bound proposed by Kovtun, Son, and Starinets using string theory methods at $T\\sim 210$ MeV. This suggests a phase transition or cross over might occur at $T\\lesssim 210$ MeV in order for the bound to remain valid. Also, it is natural for $\\eta /s$ to stay close to the minimum bound around the phase transition temperature as was recently found in heavy ion collisions.
Elongational viscosity of photo-oxidated LDPE
Rolón-Garrido, Víctor H., E-mail: victor.h.rolongarrido@tu-berlin.de, E-mail: manfred.wagner@tu-berlin.de; Wagner, Manfred H., E-mail: victor.h.rolongarrido@tu-berlin.de, E-mail: manfred.wagner@tu-berlin.de [Chair of Polymer Engineering and Polymer Physics, Berlin Institute of Technology-TU Berlin. Fasanenstr. 90. 10623 Berlin (Germany)
2014-05-15T23:59:59.000Z
Sheets of low-density polyethylene (LDPE) were photo-oxidatively treated at room temperature, and subsequently characterized rheologically in the melt state by shear and uniaxial extensional experiments. For photo-oxidation, a xenon lamp was used to irradiate the samples for times between 1 day and 6 weeks. Linear-viscoelastic characterization was performed in a temperature range of 130 to 220°C to obtain the master curve at 170°C, the reference temperature at which the elongational viscosities were measured. Linear viscoelasticity is increasingly affected by increasing photo-oxidation due to crosslinking of LDPE, as corroborated by an increasing gel fraction as determined by a solvent extraction method. The elongational measurements reveal a strong enhancement of strain hardening until a saturation level is achieved. The elongational data are analyzed in the frame work of two constitutive equations, the rubber-like liquid and the molecular stress function models. Within the experimental window, timedeformation separability is confirmed for all samples, independent of the degree of photo-oxidation.
Nonlinear bulk viscosity and the stability of accelerated expansion in FRW spacetime
G. Acquaviva; A. Beesham
2014-05-14T23:59:59.000Z
In the context of dark energy solutions, we consider a Friedmann-Robertson-Walker spacetime filled with a non-interacting mixture of dust and a viscous fluid, whose bulk viscosity is governed by the nonlinear model proposed in [15]. Through a phase space analysis of the equivalent dynamical system, existence and stability of critical solutions are established and the respective scale factors are computed. The results point towards the possibility of describing the current accelerated expansion of the Universe by means of the abovementioned nonlinear model for viscosity.
Displacement of oil from reservoir rock using graded-viscosity water
Al-Atigi, Yosef A
1974-01-01T23:59:59.000Z
experiment a total of I pore volume (PV) of fluids was injected at a constant rate of 0. 766 cc/min. The oil used had a viscosity of 30 centipoise (cp). In one case, a 1 PV bank of plain water was injected. In another case, a 1 PV bank of 30 cp polymer... solution was injected. Between the two cases, 29% of the polymer used above was utilized to make a 1/2 PV bank of graded-viscosity polymer solution and, in a separate case, to make a 0. 29 PV bank of 30 cp polymer solution. The two banks were flushed...
Displacement of oil from reservoir rock using graded-viscosity water
Al-Atigi, Yosef A
1974-01-01T23:59:59.000Z
experiment a total of I pore volume (PV) of fluids was injected at a constant rate of 0. 766 cc/min. The oil used had a viscosity of 30 centipoise (cp). In one case, a 1 PV bank of plain water was injected. In another case, a 1 PV bank of 30 cp polymer... solution was injected. Between the two cases, 29% of the polymer used above was utilized to make a 1/2 PV bank of graded-viscosity polymer solution and, in a separate case, to make a 0. 29 PV bank of 30 cp polymer solution. The two banks were flushed...
VISCOSITY AND RELAXATION APPROXIMATIONS FOR HYPERBOLIC SYSTEMS OF CONSERVATION LAWS
Tzavaras, Athanasios E.
VISCOSITY AND RELAXATION APPROXIMATIONS FOR HYPERBOLIC SYSTEMS OF CONSERVATION LAWS Athanasios E. Tzavaras Abstract. These lecture notes deal with the approximation of conservation laws via viscosity or relaxation. The following topics are covered: The general structure of viscosity and relaxation
VISCOSITY AND RELAXATION APPROXIMATIONS FOR HYPERBOLIC SYSTEMS OF CONSERVATION LAWS
Tzavaras, Athanasios E.
VISCOSITY AND RELAXATION APPROXIMATIONS FOR HYPERBOLIC SYSTEMS deal with the approximation of conservation * *laws via viscosity or relaxation. The following topics are covered: The general structure of viscosity and relaxation approximations is discu
Shear viscosity in neutron star cores
P. S. Shternin; D. G. Yakovlev
2008-08-21T23:59:59.000Z
We calculate the shear viscosity $\\eta = \\eta_{e\\mu}+\\eta_{n}$ in a neutron star core composed of nucleons, electrons and muons ($\\eta_{e\\mu}$ being the electron-muon viscosity, mediated by collisions of electrons and muons with charged particles, and $\\eta_{n}$ the neutron viscosity, mediated by neutron-neutron and neutron-proton collisions). Deriving $\\eta_{e\\mu}$, we take into account the Landau damping in collisions of electrons and muons with charged particles via the exchange of transverse plasmons. It lowers $\\eta_{e\\mu}$ and leads to the non-standard temperature behavior $\\eta_{e\\mu}\\propto T^{-5/3}$. The viscosity $\\eta_{n}$ is calculated taking into account that in-medium effects modify nucleon effective masses in dense matter. Both viscosities, $\\eta_{e\\mu}$ and $\\eta_{n}$, can be important, and both are calculated including the effects of proton superfluidity. They are presented in the form valid for any equation of state of nucleon dense matter. We analyze the density and temperature dependence of $\\eta$ for different equations of state in neutron star cores, and compare $\\eta$ with the bulk viscosity in the core and with the shear viscosity in the crust.
A new method for measuring the viscosity of nanoparticles | EMSL
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
A new method for measuring the viscosity of nanoparticles A new method for measuring the viscosity of nanoparticles Released: March 31, 2013 First direct determination of the...
Chaos, Transport, and Mesh Convergence for Fluid Mixing J. Glimm,1, 2
New York at Stoney Brook, State University of
Chaos, Transport, and Mesh Convergence for Fluid Mixing H. Lim,1 Y. Yu,1 J. Glimm,1, 2 X.-L. Li,1 in Fig. 1. The fluid interface, at late time, is volume filling. The transport coefficients (viscosity of distinct fluids produces a convoluted structure to the inter- face separating these fluids. For miscible
The Bulk Viscosity of a Pion Gas
Egang Lu; Guy D. Moore
2011-01-31T23:59:59.000Z
We compute the bulk viscosity of a gas of pions at temperatures below the QCD crossover temperature, for the physical value of pion mass, to lowest order in chiral perturbation theory. Bulk viscosity is controlled by number-changing processes which become exponentially slow at low temperatures when the pions become exponentially dilute, leading to an exponentially large bulk viscosity zeta ~ (F_0^8/m_\\pi^5) exp(2m_\\pi/T), where F_0 = 93 MeV is the pion decay constant.
Shear Viscosity from Effective Couplings of Gravitons
Rong-Gen Cai; Zhang-Yu Nie; Ya-Wen Sun
2008-12-12T23:59:59.000Z
We calculate the shear viscosity of field theories with gravity duals using Kubo-formula by calculating the Green function of dual transverse gravitons and confirm that the value of the shear viscosity is fully determined by the effective coupling of transverse gravitons on the horizon. We calculate the effective coupling of transverse gravitons for Einstein and Gauss-Bonnet gravities coupled with matter fields, respectively. Then we apply the resulting formula to the case of AdS Gauss-Bonnet gravity with $F^4$ term corrections of Maxwell field and discuss the effect of $F^4$ terms on the ratio of the shear viscosity to entropy density.
Alex Buchel; Chris Pagnutti
2009-03-02T23:59:59.000Z
We use gauge theory/string theory correspondence to study the bulk viscosity of strongly coupled, mass deformed SU(N_c) N=4 supersymmetric Yang-Mills plasma, also known as N=2^* gauge theory. For a wide range of masses we confirm the bulk viscosity bound proposed in arXiv:0708.3459. For a certain choice of masses, the theory undergoes a phase transition with divergent specific heat c_V ~ |1-T_c/T|^(-1/2). We show that, although bulk viscosity rapidly grows as T -> T_c, it remains finite in the vicinity of the critical point.
Bulk viscosity effects on elliptic flow
G. S. Denicol; T. Kodama; T. Koide; Ph. Mota
2009-09-30T23:59:59.000Z
The effects of bulk viscosity on the elliptic flow $v_{2}$ are studied using realistic equation of state and realistic transport coefficients. We find that thebulk viscosity acts in a non trivial manner on $v_{2}$. At low $p_{T}$, the reduction of $v_{2}$ is even more effective compared to the case of shear viscosity, whereas at high $p_{T}$, an enhancement of $v_{2}$ compared to the ideal case is observed. We argue that this is caused by the competition of the critical behavior of the equation of state and the transport coefficients.
Shear viscosity of $?$-stable nuclear matter
Omar Benhar; Arianna Carbone
2009-12-01T23:59:59.000Z
Viscosity plays a critical role in determining the stability of rotating neutron stars. We report the results of a calculation of the shear viscosity of $\\beta$~-~stable matter, carried out using an effective interaction based on a state-of-the-art nucleon-nucleon potential and the formalism of correlated basis functions. Within our approach the equation of state, determining the proton fraction, and the nucleon-nucleon scattering probability are consistently obtained from the same dynamical model. The results show that, while the neutron contribution to the viscosity is always dominant, above nuclear saturation density the electron contribution becomes appreciable.
Chevarunotai, Natasha
2014-11-13T23:59:59.000Z
parameters in production optimization and field development planning. Sensitivity analysis results show that production rate, reservoir permeability, fluid viscosity, and J-T coefficient are critical parameters in reservoir flowing-fluid temperature...
Using supercritical fluids to refine hydrocarbons
Yarbro, Stephen Lee
2014-11-25T23:59:59.000Z
This is a method to reactively refine hydrocarbons, such as heavy oils with API gravities of less than 20.degree. and bitumen-like hydrocarbons with viscosities greater than 1000 cp at standard temperature and pressure using a selected fluid at supercritical conditions. The reaction portion of the method delivers lighter weight, more volatile hydrocarbons to an attached contacting device that operates in mixed subcritical or supercritical modes. This separates the reaction products into portions that are viable for use or sale without further conventional refining and hydro-processing techniques. This method produces valuable products with fewer processing steps, lower costs, increased worker safety due to less processing and handling, allow greater opportunity for new oil field development and subsequent positive economic impact, reduce related carbon dioxide, and wastes typical with conventional refineries.
Viscosity and jet quenching from holographic model
Yi-hong Gao; Wei-shui Xu; Ding-fang Zeng
2007-09-23T23:59:59.000Z
We consider the backreaction of the fundamental flavor degrees of freedom on the AdS$_5$-Schwarz background, and calculate their contributions to the shear viscosity and jet-quenching parameter of the thermal quark-gluon plasma.
Viscosity at RHIC: Theory and Practice
Scott Pratt
2008-09-01T23:59:59.000Z
Hydrodynamic behavior and the associated discussions of viscosity at RHIC has inspired a r enaissance in modeling viscous hydrodynamics. An explanation of Israel-Stewart hydrodynamics is presented here, with an emphasis on the tangible benefits compared to Navier Stokes.
Randall-Sundrum model with $?viscosity
Samuel Lepe; Francisco Peńa; Joel Saavedra
2008-03-04T23:59:59.000Z
We study the effect of the inclusion of bulk brane viscosity on brane world (BW) cosmology in the framework of the Eckart's theory, we focus in the Randall-Sundrum model with negative tension on the brane.
Measurement of DWPF glass viscosity - Final Report
Harbour, J.R.
2000-02-17T23:59:59.000Z
This report details the results of a scoping study funded by the Defense Waste Processing Facility (DWPF) for the measurement of melt viscosities for simulated glasses representative of Macrobatch 2 (Tank 42/51 feed).
Tsunamis, Viscosity and the HBT Puzzle
Scott Pratt
2007-11-13T23:59:59.000Z
The equation of state and bulk and shear viscosities are shown to be able to affect the transverse dynamics of a central heavy ion collision. The net entropy, along with the femtoscopic radii are shown to be affected at the 10-20% level by both shear and bulk viscosity. The degree to which these effects help build a tsunami-like pulse is also discussed.
Viscosity anomaly in core-softened liquids
Yu. D. Fomin; V. N. Ryzhov
2013-03-18T23:59:59.000Z
The present article presents a molecular dynamics study of several anomalies of core-softened systems. It is well known that many core-softened liquids demonstrate diffusion anomaly. Usual intuition relates the diffusion coefficient to shear viscosity via Stockes-Einstein relation. However, it can break down at low temperature. In this respect it is important to see if viscosity also demonstrates anomalous behavior.
Shear viscosity of degenerate electron matter
P. S. Shternin
2008-03-27T23:59:59.000Z
We calculate the partial electron shear viscosity $\\eta_{ee}$ limited by electron-electron collisions in a strongly degenerate electron gas taking into account the Landau damping of transverse plasmons. The Landau damping strongly suppresses $\\eta_{ee}$ in the domain of ultrarelativistic degenerate electrons and modifies its %asymptotic temperature behavior. The efficiency of the electron shear viscosity in the cores of white dwarfs and envelopes of neutron stars is analyzed.
High-Temperature Viscosity Of Commercial Glasses
Hrma, Pavel R.; See, Clem A.; Lam, Oanh P.; Minister, Kevin B.
2005-01-01T23:59:59.000Z
Viscosity was measured for six types of commercial glasses: low-expansion-borosilicate glasses, E glasses, fiberglass wool glasses, TV panel glasses, container glasses, and float glasses. Viscosity data were obtained with rotating spindle viscometers within the temperature range between 900°C and 1550°C; the viscosity varied from 1 Pa?s to 750 Pa?s. Arrhenius coefficients were calculated for individual glasses and linear models were applied to relate them to the mass fractions of 11 major components (SiO2, CaO, Na2O, Al2O3, B2O3, BaO, SrO, K2O, MgO, PbO, and ZrO2) and 12 minor components (Fe2O3, ZnO, Li2O, TiO2, CeO2, F, Sb2O3, Cr2O3, As2O3, MnO2, SO3, and Co3O4). The models are recommended for glasses containing 42 to 84 mass% SiO2 to estimate viscosities or temperatures at a constant viscosity for melts within both the temperature range from 1100°C to 1550°C and viscosity range from 10 to 400 Pa?s.
Holographic Spontaneous Parity Breaking and Emergent Hall Viscosity and Angular Momentum
Dam Thanh Son; Chaolun Wu
2014-08-30T23:59:59.000Z
We study the spontaneous parity breaking and generating of Hall viscosity and angular momentum in holographic p+ip model, which can describe strongly-coupled chiral superfluid states in many quantum systems. The dual gravity theory, an SU(2) gauge field minimally coupled to Einstein gravity, is parity-invariant but allows a black hole solution with vector hair corresponding to a parity-broken superfluid state. We show that this state possesses a non-vanishing parity-odd transport coefficient -- Hall viscosity -- and an angular momentum density. We first develop an analytic method to solve this model near the critical regime and to take back-reactions into account. Then we solve the equation for the tensor mode fluctuations and obtain the expression for Hall viscosity via Kubo formula. We also show that a non-vanishing angular momentum density can be obtained through the vector mode fluctuations and the corresponding boundary action. We give analytic results of both Hall viscosity and angular momentum density near the critical regime in terms of physical parameters. The near-critical behavior of Hall viscosity is different from that obtained from a gravitational Chern-Simons model. We find that the magnitude of Hall viscosity to angular momentum density ratio is numerically consistent with being equal to 1/2 at large SU(2) coupling corresponding to the probe limit, in agreement with previous results obtained for various quantum fluid systems and from effective theory approaches. In addition, we find the shear viscosity to entropy density ratio remains above the universal bound.
Entropy viscosity Jean-Luc Guermond, B. Popov
Guermond, Jean-Luc
Entropy viscosity Jean-Luc Guermond, B. Popov Department of Mathematics Texas A&M University-Luc Guermond, B. Popov Residual/Entropy viscosity #12;Acknowledgments Collaborator: Richard Pasquetti, Univ/Entropy viscosity #12;Outline 1 TRANSPORT EQUATION Jean-Luc Guermond, B. Popov Residual/Entropy viscosity #12
VISCOSITY SOLUTIONS TO DEGENERATE COMPLEX MONGE-AMP`ERE EQUATIONS
Boyer, Edmond
VISCOSITY SOLUTIONS TO DEGENERATE COMPLEX MONGE-AMP`ERE EQUATIONS PHILIPPE EYSSIDIEUX, VINCENT an alternative approach based on the concept of viscosity solutions and compare systematically viscosity concepts PDE approach to second-order degenerate elliptic equations is the method of viscosity solutions
The nucleon thermal width due to pion-baryon loops and its contribution in Shear viscosity
Ghosh, Sabyasachi
2015-01-01T23:59:59.000Z
In the real-time thermal field theory, the standard expression of shear viscosity for the nucleonic constituents is derived from the two point function of nucleonic viscous stress tensors at finite temperature and density. The finite thermal width or Landau damping is traditionally included in the nucleon propagators. This thermal width is calculated from the in-medium self-energy of nucleon for different possible pion-baryon loops. The dynamical part of nucleon-pion-baryon interactions are taken care by the effective Lagrangian densities of standard hadronic model. The shear viscosity to entropy density ratio of nucleonic component decreases with the temperature and increases with the nucleon chemical potential. However, adding the contribution of pionic component, total viscosity to entropy density ratio also reduces with the nucleon chemical potential when the mixing effect between pion and nucleon components in the mixed gas is considered. Within the hadronic domain, viscosity to entropy density ratio of ...
Effective viscosity of active suspensions: Three-dimensional numerical modeling
Levan Jibuti; Walter Zimmermann; Salima Rafaď; Philippe Peyla
2014-12-10T23:59:59.000Z
A three-dimensional model is proposed for Chlamydomonas Reinhardtii swimming with a breaststroke-like beating of its two flagella. The model reveals unusual angular orbits of the active swimmer under a linear shear flow. Namely, the swimmer sustains orientation transiently across the flow when flagella plane is perpendicular to the shear plane, and amplify the shear-induced rotation along the flow. Such behavior is a result of the interplay between shear-induced deformation and swimmer's periodic beating motion that exerts internal torques on the torque-free swimmer. This particular behavior has some significant consequences on the rheological properties of the suspension that tends to confirm previous experimental results [Phys. Rev. Lett. 104, 098102 (2010)]. We calculated the intrinsic viscosity of the suspension with such isolated modeled microswimmers (dilute case) in shear flow using numerical simulations based on Rotne-Prager approximation. The results show an increased intrinsic viscosity for active swimmer suspensions in comparison to non-active ones in accordance with previous experimental measurements. A major enhancement of the active swimmer viscosity occurs due to the effectively extended shape of the deformable swimming cells. We also recover the experimentally observed shear thinning behavior.
Viscosity of copper oxide nanoparticles dispersed in ethylene glycol and water mixture
Namburu, Praveen K.; Kulkarni, Devdatta P.; Das, Debendra K. [Department of Mechanical Engineering, University of Alaska, Fairbanks, P.O. Box 755905, Fairbanks, AK 99775-5905 (United States); Misra, Debasmita [Department of Mining and Geological Engineering, University of Alaska, Fairbanks, P.O. Box 755905, Fairbanks, AK 99775-5905 (United States)
2007-11-15T23:59:59.000Z
Nanofluids are new kinds of fluids engineered by dispersing nanoparticles in base fluids. This paper presents an experimental investigation of rheological properties of copper oxide nanoparticles suspended in 60:40 (by weight) ethylene glycol and water mixture. Nanofluids of particle volume percentage ranging from 0% to 6.12% were tested. The experiments were carried over temperatures ranging from -35 C to 50 C to demonstrate their applicability in cold regions. For the particle volume concentrations tested, nanofluids exhibited Newtonian behavior. An experimental correlation was developed based on the data, which relates viscosity with particle volume percent and the nanofluid temperature. (author)
Transition to Turbulence in Shear-Thinning Fluids
Zhen, Ni
2014-04-23T23:59:59.000Z
In this dissertation, the effects of a shear-thinning fluid on the evolution of a hairpin vortex are investigated. The fluid viscosity is determined using a power law model and direct numerical simulations are performed using a pseudo-spectral code...
Shear Viscosity of a Hot Pion Gas
Robert Lang; Norbert Kaiser; Wolfram Weise
2012-09-04T23:59:59.000Z
The shear viscosity of an interacting pion gas is studied using the Kubo formalism as a microscopic description of thermal systems close to global equilibrium. We implement the skeleton expansion in order to approximate the retarded correlator of the viscous part of the energy-momentum tensor. After exploring this in $g\\phi^4$ theory we show how the skeleton expansion can be consistently applied to pions in chiral perturbation theory. The shear viscosity $\\eta$ is determined by the spectral width, or equivalently, the mean free path of pions in the heat bath. We derive a new analytical result for the mean free path which is well-conditioned for numerical evaluation and discuss the temperature and pion-mass dependence of the mean free path and the shear viscosity. The ratio $\\eta/s$ of the interacting pion gas exceeds the lower bound $1/4\\pi$ from AdS/CFT correspondence.
Determination of several variables affecting laboratory measurements of cross-linked fracture fluids
Wilson, Matilda Jane
1982-01-01T23:59:59.000Z
Viscosity for Run 48 at 150'F . 23 Effect of Shear Rate and Time on Apparent Viscosity for Run Al at 190'F . . . . . . . . . . . . . . . . 42 24 Effect of Shear Rate and Time on Apparent Viscosity for Run 48 at 196'F . . . . . . . . . . . . . . . . 4 3... SHEAR RATE o) PSEUDOPLASTIC NEWTONIAN SHEAR RATE b) Figure 3 ? Fluid Flow Behavior shear rate. These fluids are also called shear-thinning fluids. The power law (Ostwald-dewaele) model is the most popular model used to describe the flow behavior...
Shear Viscosity of a Unitary Fermi Gas
Gabriel Wlaz?owski; Piotr Magierski; Joaquín E. Drut
2012-07-12T23:59:59.000Z
We present the first ab initio determination of the shear viscosity eta of the Unitary Fermi Gas, based on finite temperature quantum Monte Carlo calculations and the Kubo linear-response formalism. We determine the temperature dependence of the shear viscosity to entropy density ratio eta/s. The minimum of eta/s appears to be located above the critical temperature for the superfluid-to-normal phase transition with the most probable value being eta/s approx 0.2 hbar/kB, which almost saturates the Kovtun-Son-Starinets universal value hbar/(4 pi kB).
Viscosity of a nanoconfined liquid during compression
Khan, Shah H. [Institute of Physics and Electronics, University of Peshawar, Peshawar 25120 (Pakistan); Kramkowski, Edward L.; Ochs, Peter J.; Wilson, David M.; Hoffmann, Peter M., E-mail: hoffmann@wayne.edu [Department of Physics and Astronomy, Wayne State University, Detroit, Michigan 48201 (United States)
2014-01-13T23:59:59.000Z
The viscous behavior of liquids under nanoconfinement is not well understood. Using a small-amplitude atomic force microscope, we found bulk-like viscosity in a nanoconfined, weakly interacting liquid. A further decrease in viscosity was observed at confinement sizes of a just few molecular layers. Overlaid over the continuum viscous behavior, we measured non-continuum stiffness and damping oscillations. The average stiffness of the confined liquid was found to scale linearly with the size of the confining tip, while the damping scales with the radius of curvature of the tip end.
Geothermal fracture stimulation technology. Volume III. Geothermal fracture fluids
Not Available
1981-01-01T23:59:59.000Z
A detailed study of all available and experimental frac fluid systems is presented. They have been examined and tested for physical properties that are important in the stimulation of hot water geothermal wells. These fluids consist of water-based systems containing high molecular weight polymers in the uncrosslinked and crosslinked state. The results of fluid testing for many systems are summarized specifically at geothermal conditions or until breakdown occurs. Some of the standard tests are ambient viscosity, static aging, high temperature viscosity, fluid-loss testing, and falling ball viscosity at elevated temperatures and pressures. Results of these tests show that unalterable breakdown of the polymer solutions begins above 300/sup 0/F. This continues at higher temperatures with time even if stabilizers or other high temperature additives are included.
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.
Viscosity to entropy ratio at extremality
Sayan K. Chakrabarti; Sachin Jain; Sudipta Mukherji
2010-01-19T23:59:59.000Z
Assuming gauge theory realization at the boundary, we show that the viscosity to entropy ratio is 1/(4 pi) where the bulk is represented by a large class of extremal black holes in anti-de Sitter space. In particular, this class includes multiple R-charged black holes in various dimensions.
Computation of Shear Viscosity: A Systems Approach
Wen, John Ting-Yung
Institute Troy, NY 12180. Emails: {hurstj,wenj}@rpi.edu Abstract-- Macroscopic material transport properties. Linearizing this map about an equilibrated trajectory results in a linear time varying system. By freezing]. In particular, macroscopic transport properties such as viscosity, diffusivity, conductivity, etc., may
Metzger, Bloen
particle of radius a settles in a viscous fluid of viscosity Âµ, the drag force D = -6ÂµaU exerted). The amplitude of the generated flow field decays very slowly, like the inverse of the distance to the sphere. We of particles. When two identical spheres sediment in a viscous fluid, the fluid motion induced by the fall
Sutharsan, Jeyanthy
2009-01-01T23:59:59.000Z
Synthesis and Evaluation as Viscosity Sensors IntroductionSynthesis and Evaluation as Viscosity Sensors14and evaluation of these compounds as viscosity sensors. The
Entropy production at freeze-out from dissipative fluids
E. Molnar
2007-09-17T23:59:59.000Z
Entropy production due to shear viscosity during the continuous freeze-out of a longitudinally expanding dissipative fluid is addressed. Assuming the validity of the fluid dynamical description during the continuous removal of interacting matter we estimated a small entropy production as function of the freeze-out duration and the ratio of dissipative to non-dissipative quantities in case of a relativistic massless pion fluid.
Shear viscosity of CFT plasma at finite coupling
Alex Buchel
2008-05-29T23:59:59.000Z
We present evidence for the universality of the shear viscosity of conformal gauge theory plasmas beyond infinite coupling. We comment of subtleties of computing the shear viscosity in effective models of gauge/gravity correspondence rather than in string theory.
Shear Viscosity from the Effective Coupling of Gravitons
Rong-Gen Cai; Zhang-Yu Nie; Ya-Wen Sun
2010-07-14T23:59:59.000Z
We review the progress in the holographic calculation of shear viscosity for strongly coupled field theories. We focus on the calculation of shear viscosity from the effective coupling of transverse gravitons and present some explicit examples.
Plasma Viscosity with Mass Transport in Spherical ICF Implosion Simulations
Vold, Erik L; Ortega, Mario I; Moll, Ryan; Fenn, Daniel; Molvig, Kim
2015-01-01T23:59:59.000Z
The effects of viscosity and small-scale atomic-level mixing on plasmas in inertial confinement fusion (ICF) currently represent challenges in ICF research. Many current ICF hydrodynamic codes ignore the effects of viscosity though recent research indicates viscosity and mixing by classical transport processes may have a substantial impact on implosion dynamics. We have implemented a Lagrange hydrodynamic code in one-dimensional spherical geometry with plasma viscosity and mass transport and including a three temperature model for ions, electrons, and radiation treated in a gray radiation diffusion approximation. The code is used to study ICF implosion differences with and without plasma viscosity and to determine the impacts of viscosity on temperature histories and neutron yield. It was found that plasma viscosity has substantial impacts on ICF shock dynamics characterized by shock burn timing, maximum burn temperatures, convergence ratio, and time history of neutron production rates. Plasma viscosity reduc...
Viscosities of natural gases at high pressures and high temperatures
Viswanathan, Anup
2007-09-17T23:59:59.000Z
Estimation of viscosities of naturally occurring petroleum gases provides the information needed to accurately work out reservoir-engineering problems. Existing models for viscosity prediction are limited by data, especially ...
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...
Viscosity, hard sphere diameter and interionic potential for liquid lead
Boyer, Edmond
L-347 Viscosity, hard sphere diameter and interionic potential for liquid lead G. Chaussemy The Macedo-Litovitz equation for a hard sphere liquid provides a satisfactory model for the viscosity of lead and molecular dynamics. The activation energy for viscosity (0.07 eV) is similar to the height of the interionic
Viscosity dependence of geminate recombination efficiency after bimolecular charge separation
Burshtein, Anatoly
Viscosity dependence of geminate recombination efficiency after bimolecular charge separation A. A viscosity dependence. As a result the latter becomes nonmonotonous, provided the kinetic controlled ionization gives way to a diffusional one, creating the more remote ions the higher the solvent viscosity
VISCOSITY SOLUTIONS OF FULLY NONLINEAR ELLIPTIC PATH DEPENDENT PDES
Paris-Sud XI, Université de
VISCOSITY SOLUTIONS OF FULLY NONLINEAR ELLIPTIC PATH DEPENDENT PDES ZHENJIE REN Abstract, inspired by [3], we define the viscosity solution, by using the nonlinear expectation. The paper contains , that for any bounded viscosity subsolution u1 and Key words and phrases. Path dependent PDEs, Dirichlet problem
VISCOSITY SOLUTIONS OF HAMILTONJACOBI EQUATIONS WITH DISCONTINUOUS COEFFICIENTS
VISCOSITY SOLUTIONS OF HAMILTONJACOBI EQUATIONS WITH DISCONTINUOUS COEFFICIENTS GIUSEPPE MARIA of viscosity solution to the Cauchy problem, and that the front tracking algorithm yields an L contractive semigroup. We define a viscosity solution by treating the discontinuities in the coefficients analogously
VISCOSITY SOLUTIONS OF HAMILTON-JACOBI EQUATIONS, AND ASYMPTOTICS FOR
Gomes, Diogo
VISCOSITY SOLUTIONS OF HAMILTON-JACOBI EQUATIONS, AND ASYMPTOTICS FOR HAMILTONIAN SYSTEMS DIOGO:dgomes@math.ist.utl.pt Abstract. In this paper we apply the theory of viscosity solu- tions of Hamilton-Jacobi equations) that are characteristics of viscosity solutions of Hamilton-Jacobi equations, (2) H(P + Dxu, x) = H
VISCOSITY OF CONCENTRATED SUSPENSIONS: INFLUENCE OF CLUSTER FORMATION
Boyer, Edmond
1 VISCOSITY OF CONCENTRATED SUSPENSIONS: INFLUENCE OF CLUSTER FORMATION V.Starov1 , V.Zhdanov1 , M and these forces determine both structure and size of clusters. We assume that viscosity of concentrated suspension of viscosity on a concentration of dispersed particles taking into account cluster formation, is deduced. Under
Viscosity and Relaxation Approximation for Hyperbolic Systems of Conservation Laws
Tzavaras, Athanasios E.
Viscosity and Relaxation Approximation for Hyperbolic Systems of Conservation Laws Athanasios E with the approximation of conservation laws via viscosity or relaxation. The following topics are covered: The general structure of viscosity and relaxation approximations is discussed, as suggested by the second law
Bulk viscosity of gauge theory plasma at strong coupling
Alex Buchel
2007-09-01T23:59:59.000Z
We propose a lower bound on bulk viscosity of strongly coupled gauge theory plasmas. Using explicit example of the N=2^* gauge theory plasma we show that the bulk viscosity remains finite at a critical point with a divergent specific heat. We present an estimate for the bulk viscosity of QGP plasma at RHIC.
VISCOSITY SOLUTIONS OF HAMILTON-JACOBI EQUATIONS, AND ASYMPTOTICS FOR
VISCOSITY SOLUTIONS OF HAMILTON-JACOBI EQUATIONS, AND ASYMPTOTICS FOR HAMILTONIAN SYSTEMS DIOGO. In this paper we apply the theory of viscosity solu- tions of Hamilton-Jacobi equations to understand) with cer- tain minimizing properties) and viscosity solutions of Hamilton-Jacobi equations (2) H(P + Dxu, x
Bulk viscosity and r-modes of neutron stars
Debarati Chatterjee; Debades Bandyopadhyay
2008-08-08T23:59:59.000Z
The bulk viscosity due to the non-leptonic process involving hyperons in $K^-$ condensed matter is discussed here. We find that the bulk viscosity is modified in a superconducting phase. Further, we demonstrate how the exotic bulk viscosity coefficient influences $r$-modes of neutron stars which might be sources of detectable gravitational waves.
Viscosity, Black Holes, and Quantum Field Theory
D. T. Son; A. O. Starinets
2007-07-11T23:59:59.000Z
We review recent progress in applying the AdS/CFT correspondence to finite-temperature field theory. In particular, we show how the hydrodynamic behavior of field theory is reflected in the low-momentum limit of correlation functions computed through a real-time AdS/CFT prescription, which we formulate. We also show how the hydrodynamic modes in field theory correspond to the low-lying quasinormal modes of the AdS black p-brane metric. We provide a proof of the universality of the viscosity/entropy ratio within a class of theories with gravity duals and formulate a viscosity bound conjecture. Possible implications for real systems are mentioned.
On the contribution of plasminos to the shear viscosity of a hot and dense Yukawa-Fermi gas
N. Sadooghi; F. Taghinavaz
2015-04-16T23:59:59.000Z
Using the standard Green-Kubo formalism, we determine the shear viscosity $\\eta$ of a hot and dense Yukawa-Fermi gas. In particular, we study the effect of particle and plasmino excitations on thermal properties of the fermionic part of the shear viscosity, and explore the effects of thermal corrections to particle masses on bosonic and fermionic shear viscosities, $\\eta_b$ and $\\eta_f$. It turns out that the effects of plasminos on $\\eta_f$ become negligible with increasing (decreasing) temperature (chemical potential).
Factors affecting viscosity changes in corn
McGill, Kendra Louise
1995-01-01T23:59:59.000Z
in the wet milling industry to evaluate unmodified, acid modified, oxidized and derivatized starches. This machine operates with a water bath maintained at boiling point with live steam. The samples are cooked in a controlled manner with fixed time... the force supplied by the sample to spindle rotation. This machine measures in centipoise (cps) and can be read directly from the dial. Viscosities of 1, 000 to 64, 000 cps can be measured, This machine has the advantages of ease of operation, simple...
RELAP-7 Numerical Stabilization: Entropy Viscosity Method
R. A. Berry; M. O. Delchini; J. Ragusa
2014-06-01T23:59:59.000Z
The RELAP-7 code is the next generation nuclear reactor system safety analysis code being developed at the Idaho National Laboratory (INL). The code is based on the INL's modern scientific software development framework, MOOSE (Multi-Physics Object Oriented Simulation Environment). The overall design goal of RELAP-7 is to take advantage of the previous thirty years of advancements in computer architecture, software design, numerical integration methods, and physical models. The end result will be a reactor systems analysis capability that retains and improves upon RELAP5's capability and extends the analysis capability for all reactor system simulation scenarios. RELAP-7 utilizes a single phase and a novel seven-equation two-phase flow models as described in the RELAP-7 Theory Manual (INL/EXT-14-31366). The basic equation systems are hyperbolic, which generally require some type of stabilization (or artificial viscosity) to capture nonlinear discontinuities and to suppress advection-caused oscillations. This report documents one of the available options for this stabilization in RELAP-7 -- a new and novel approach known as the entropy viscosity method. Because the code is an ongoing development effort in which the physical sub models, numerics, and coding are evolving, so too must the specific details of the entropy viscosity stabilization method. Here the fundamentals of the method in their current state are presented.
Shear viscosity of a nonperturbative gluon plasma
Dmitri Antonov
2012-02-10T23:59:59.000Z
Shear viscosity is evaluated within a model of the gluon plasma, which is based entirely on the stochastic nonperturbative fields. We consider two types of excitations of such fields, which are characterized by the thermal correlation lengths ~ 1/(g^2 T) and ~ 1/(g^4 T), where "g" is the finite-temperature Yang-Mills coupling. Excitations of the first type correspond to the genuine nonperturbative stochastic Yang-Mills fields, while excitations of the second type mimic the known result for the shear viscosity of the perturbative Yang-Mills plasma. We show that the excitations of the first type produce only an O(g^{10})-correction to this result. Furthermore, a possible interference between excitations of these two types yields a somewhat larger, O(g^7), correction to the leading perturbative Yang-Mills result. Our analysis is based on the Fourier transformed Euclidean Kubo formula, which represents an integral equation for the shear spectral density. This equation is solved by seeking the spectral density in the form of the Lorentzian Ans\\"atze, whose widths are defined by the two thermal correlation lengths and by their mean value, which corresponds to the said interference between the two types of excitations. Thus, within one and the same formalism, we reproduce the known result for the shear viscosity of the perturbative Yang-Mills plasma, and account for possible nonperturbative corrections to it.
Bulk viscosity of QCD matter near the critical temperature
D. Kharzeev; K. Tuchin
2007-05-29T23:59:59.000Z
Kubo's formula relates bulk viscosity to the retarded Green's function of the trace of the energy-momentum tensor. Using low energy theorems of QCD for the latter we derive the formula which relates the bulk viscosity to the energy density and pressure of hot matter. We then employ the available lattice QCD data to extract the bulk viscosity as a function of temperature. We find that close to the deconfinement temperature bulk viscosity becomes large, with viscosity-to-entropy ratio zeta/s about 1.
The Viscosity Bound Conjecture and Hydrodynamics of M2-Brane Theory at Finite Chemical Potential
Omid Saremi
2006-05-24T23:59:59.000Z
Kovtun, Son and Starinets have conjectured that the viscosity to entropy density ratio $\\eta/s$ is always bounded from below by a universal multiple of $\\hbar$ i.e., $\\hbar/(4\\pi k_{B})$ for all forms of matter. Mysteriously, the proposed viscosity bound appears to be saturated in all computations done whenever a supergravity dual is available. We consider the near horizon limit of a stack of M2-branes in the grand canonical ensemble at finite R-charge densities, corresponding to non-zero angular momentum in the bulk. The corresponding four-dimensional R-charged black hole in Anti-de Sitter space provides a holographic dual in which various transport coefficients can be calculated. We find that the shear viscosity increases as soon as a background R-charge density is turned on. We numerically compute the few first corrections to the shear viscosity to entropy density ratio $\\eta/s$ and surprisingly discover that up to fourth order all corrections originating from a non-zero chemical potential vanish, leaving the bound saturated. This is a sharp signal in favor of the saturation of the viscosity bound for event horizons even in the presence of some finite background field strength. We discuss implications of this observation for the conjectured bound.
Shear viscosity of the gluon plasma in the stochastic-vacuum approach
Dmitri Antonov
2009-05-20T23:59:59.000Z
Shear viscosity of the gluon plasma in SU(3) YM theory is calculated nonperturbatively, within the stochastic vacuum model. The result for the ratio of the shear viscosity to the entropy density, proportional to the squared chromo-magnetic gluon condensate and the fifth power of the correlation length of the chromo-magnetic vacuum, falls off with the increase of temperature. At temperatures larger than the deconfinement critical temperature by a factor of 2, this fall-off is determined by the sixth power of the temperature-dependent strong-coupling constant and yields an asymptotic approach to the conjectured lower bound of 1/(4\\pi), achievable in {\\cal N}=4 SYM theory. As a by-product of the calculation, we find a particular form of the two-point correlation function of gluonic field strengths, which is the only one consistent with the Lorentzian shape of the shear-viscosity spectral function.
Flow regimes for fluid injection into a confined porous medium
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Zheng, Zhong; Guo, Bo; Christov, Ivan C.; Celia, Michael A.; Stone, Howard A.
2015-02-24T23:59:59.000Z
We report theoretical and numerical studies of the flow behaviour when a fluid is injected into a confined porous medium saturated with another fluid of different density and viscosity. For a two-dimensional configuration with point source injection, a nonlinear convection–diffusion equation is derived to describe the time evolution of the fluid–fluid interface. In the early time period, the fluid motion is mainly driven by the buoyancy force and the governing equation is reduced to a nonlinear diffusion equation with a well-known self-similar solution. In the late time period, the fluid flow is mainly driven by the injection, and the governingmore »equation is approximated by a nonlinear hyperbolic equation that determines the global spreading rate; a shock solution is obtained when the injected fluid is more viscous than the displaced fluid, whereas a rarefaction wave solution is found when the injected fluid is less viscous. In the late time period, we also obtain analytical solutions including the diffusive term associated with the buoyancy effects (for an injected fluid with a viscosity higher than or equal to that of the displaced fluid), which provide the structure of the moving front. Numerical simulations of the convection–diffusion equation are performed; the various analytical solutions are verified as appropriate asymptotic limits, and the transition processes between the individual limits are demonstrated.« less
Pumping viscoelastic two-fluid media
Hirofumi Wada
2010-04-08T23:59:59.000Z
Using a two-fluid model for viscoelastic polymer solutions, we study analytically fluid transport driven by a transverse, small amplitude traveling wave propagation. The pumping flow far from the waving boundary is shown to be strongly wave number and viscosity dependent, in contrast to a viscous Newtonian fluid. We find the two qualitatively different regimes: In one regime relevant to small wave numbers, the fluidic transport is almost the same as the Newtonian case, and uniform viscoelastic constitutive equations provide a good approximation. In the other regime, the pumping is substantially decreased because of the gel-like character. The boundary separating these two regimes is clarified. Our results suggest possible needs of two-fluid descriptions for the transport and locomotion in biological fluids with cilia and flagella.
From Thermodynamics to the Bound on Viscosity
Shahar Hod
2009-07-07T23:59:59.000Z
We show that the generalized second law of thermodynamics may shed much light on the mysterious Kovtun-Son-Starinets (KSS) bound on the ratio of viscosity to entropy density. In particular, we obtain the lower bound $\\eta/s +O(\\eta^3/s^3)\\geq 1/4\\pi$. Furthermore, for conformal field theories we obtain a new fundamental bound on the value of the relaxation coefficient $\\tau_{\\pi}$ of causal hydrodynamics, which has been the focus of much recent attention: $(\\tau_{\\pi}T)^2\\geq {{(\\sqrt{3}-1)}/{2\\pi^2}}$.
The viscosity bound in string theory
Aninda Sinha; Robert C. Myers
2009-09-11T23:59:59.000Z
The ratio of shear viscosity to entropy density $\\eta/s$ of any material in nature has been conjectured to have a lower bound of $1/4\\pi$, the famous KSS bound. We examine string theory models for evidence in favour of and against this conjecture. We show that in a broad class of models quantum corrections yield values of $\\eta/s$ just above the KSS bound. However, incorporating matter fields in the fundamental representation typically leads to violations of this bound. We also outline a program to extend AdS/CFT methods to RHIC phenomenology.
Shear viscosity and out of equilibrium dynamics
Andrej El; Zhe Xu; Carsten Greiner; Azwinndini Muronga
2009-06-18T23:59:59.000Z
Using Grad's method, we calculate the entropy production and derive a formula for the second-order shear viscosity coefficient in a one-dimensionally expanding particle system, which can also be considered out of chemical equilibrium. For a one-dimensional expansion of gluon matter with Bjorken boost invariance, the shear tensor and the shear viscosity to entropy density ratio $\\eta/s$ are numerically calculated by an iterative and self-consistent prescription within the second-order Israel-Stewart hydrodynamics and by a microscopic parton cascade transport theory. Compared with $\\eta/s$ obtained using the Navier-Stokes approximation, the present result is about 20% larger at a QCD coupling $\\alpha_s \\sim 0.3$(with $\\eta/s\\approx 0.18$) and is a factor of 2-3 larger at a small coupling $\\alpha_s \\sim 0.01$. We demonstrate an agreement between the viscous hydrodynamic calculations and the microscopic transport results on $\\eta/s$, except when employing a small $\\alpha_s$. On the other hand, we demonstrate that for such small $\\alpha_s$, the gluon system is far from kinetic and chemical equilibrium, which indicates the break down of second-order hydrodynamics because of the strong noneqilibrium evolution. In addition, for large $\\alpha_s$ ($0.3-0.6$), the Israel-Stewart hydrodynamics formally breaks down at large momentum $p_T\\gtrsim 3$ GeV but is still a reasonably good approximation.
Shear Viscosity in a CFL Quark Star
Cristina Manuel; Antonio Dobado; Felipe J. Llanes-Estrada
2005-09-30T23:59:59.000Z
We compute the mean free path and shear viscosity in the color-flavor locked (CFL) phase of dense quark matter at low temperature T, when the contributions of mesons, quarks and gluons to the transport coefficients are Boltzmann suppressed. CFL quark matter displays superfluid properties, and transport phenomena in such cold regime are dominated by phonon-phonon scattering. We study superfluid phonons within thermal field theory and compute the mean free path associated to their most relevant collision processes. Small-angle processes turn out to be more efficient in slowing transport phenomena in the CFL matter, while the mean free path relevant for the shear viscosity is less sensitive to collinear scattering due to the presence of zero modes in the Boltzmann equation. In analogy with superfluid He4, we find the same T power law for the superfluid phonon damping rate and mean free path. Our results are relevant for the study of rotational properties of compact stars, and correct wrong estimates existing in the literature.
Transport in non-conformal holographic fluids
Shailesh Kulkarni; Bum-Hoon Lee; Jae-Hyuk Oh; Chanyong Park; Raju Roychowdhury
2013-03-06T23:59:59.000Z
We have considered non-conformal fluid dynamics whose gravity dual is a certain Einstein dilaton system with Liouville type dilaton potential, characterized by an intrinsic parameter $\\eta$. We have discussed the Hawking-Page transition in this framework using hard-wall model and it turns out that the critical temperature of the Hawking-Page transition encapsulates a non-trivial dependence on $\\eta$. We also obtained transport coefficients such as AC conductivity, shear viscosity and diffusion constant in the hydrodynamic limit, which show non-trivial $\\eta$ dependent deviations from those in conformal fluids, although the ratio of the shear viscosity to entropy density is found to saturate the universal bound. Some of the retarded correlators are also computed in the high frequency limit for case study.
On Eling-Oz formula for the holographic bulk viscosity
Alex Buchel
2011-05-09T23:59:59.000Z
Recently Eling and Oz [1] proposed a simple formula for the bulk viscosity of holographic plasma. They argued that the formula is valid in the high temperature (near-conformal) regime, but is expected to break down at low temperatures. We point out that the formula is in perfect agreement with the previous computations of the bulk viscosity of the cascading plasma [2,3], as well as with the previous computations of the bulk viscosity of N=2^* plasma [4,5]. In the latter case it correctly reproduces the critical behaviour of the bulk viscosity in the vicinity of the critical point with the vanishing speed of sound.
Computing the viscosity of the QGP on the lattice
Harvey B. Meyer
2008-05-29T23:59:59.000Z
I review the recent progress made in calculating shear and bulk viscosity on the lattice, and discuss ways to improve the calculation.
Coalescence of bubbles and drops in an outer fluid
Joseph D. Paulsen; Rémi Carmigniani; Anerudh Kannan; Justin C. Burton; Sidney R. Nagel
2014-07-24T23:59:59.000Z
When two liquid drops touch, a microscopic connecting liquid bridge forms and rapidly grows as the two drops merge into one. Whereas coalescence has been thoroughly studied when drops coalesce in vacuum or air, many important situations involve coalescence in a dense surrounding fluid, such as oil coalescence in brine. Here we study the merging of gas bubbles and liquid drops in an external fluid. Our data indicate that the flows occur over much larger length scales in the outer fluid than inside the drops themselves. Thus we find that the asymptotic early regime is always dominated by the viscosity of the drops, independent of the external fluid. A phase diagram showing the crossovers into the different possible late-time dynamics identifies a dimensionless number that signifies when the external viscosity can be important.
Fluid-Rock Characterization and Interactions in NMR Well Logging
Hirasaki, George J.; Mohanty, Kishore K.
2003-02-10T23:59:59.000Z
The objective of this project was to characterize the fluid properties and fluid-rock interactions which are needed for formation evaluation by NMR well logging. NMR well logging is finding wide use in formation evaluation. The formation parameters commonly estimated were porosity, permeability, and capillary bound water. Special cases include estimation of oil viscosity, residual oil saturation, location of oil/water contact, and interpretation on whether the hydrocarbon is oil or gas.
Jet momentum balance independent of shear viscosity
R. B. Neufeld
2012-02-24T23:59:59.000Z
Jet momentum balance measurements, such as those recently performed by the CMS collaboration, provide an opportunity to quantify the energy transferred from a parton shower to the underlying medium in heavy-ion collisions. Specifically, I argue that the Cooper-Frye freezeout distribution associated with the energy and momentum deposited by the parton shower is controlled to a significant extent by the distribution of the underlying bulk matter and independent of the details of how deposited energy is redistributed in the medium, which is largely determined by transport coefficients such as shear viscosity. Thus by matching the distribution of momentum associated with the secondary jet in such measurements to the thermal distribution of the underlying medium, one can obtain a model independent estimate on the amount of parton shower energy deposited.
On bulk viscosity and moduli decay
M. Laine
2010-11-21T23:59:59.000Z
This pedagogically intended lecture, one of four under the header "Basics of thermal QCD", reviews an interesting relationship, originally pointed out by Bodeker, that exists between the bulk viscosity of Yang-Mills theory (of possible relevance to the hydrodynamics of heavy ion collision experiments) and the decay rate of scalar fields coupled very weakly to a heat bath (appearing in some particle physics inspired cosmological scenarios). This topic serves, furthermore, as a platform on which a number of generic thermal field theory concepts are illustrated. The other three lectures (on the QCD equation of state and the rates of elastic as well as inelastic processes experienced by heavy quarks) are recapitulated in brief encyclopedic form.
Viscosity of ?-pinene secondary organic material and implications for particle growth and reactivity
Renbaum-Wolff, Lindsay; Grayson, James W.; Bateman, Adam P.; Kuwata, Mikinori; Sellier, Mathieu; Murray, Benjamin J.; Shilling, John E.; Martin, Scot T.; Bertram, Allan K.
2013-05-14T23:59:59.000Z
Particles composed of secondary organic material (SOM) are abundant in the lower troposphere and play important roles in climate, air quality, and health. The viscosity of these particles is a fundamental property that is presently poorly quantified for conditions relevant to the lower troposphere. Using two new techniques, namely a bead-mobility technique and a poke-flow technique, in conjunction with simulations of fluid flow, we measure the viscosity of the watersoluble component of SOM produced by ?-pinene ozonolysis. The viscosity is comparable to that of honey at 90% relative humidity (RH), comparable to that of peanut butter at 70% RH and greater than or comparable to that of bitumen for ? 30% RH, implying that the studied SOM ranges from liquid to semisolid/solid at ambient relative humidities. With the Stokes-Einstein relation, the measured viscosities further imply that the growth and evaporation of SOM by the exchange of organic molecules between the gas and condensed phases may be confined to the surface region when RH ? 30%, suggesting the importance of an adsorption-type mechanism for partitioning in this regime. By comparison, for RH ? 70% partitioning of organic molecules may effectively occur by an absorption mechanism throughout the bulk of the particle. Finally, the net uptake rates of semi-reactive atmospheric oxidants such as O3 are expected to decrease by two to five orders of magnitude for a change in RH from 90% to ? 30% RH, with possible implications for the rates of chemical aging of SOM particles in the atmosphere.
Sensor for viscosity and shear strength measurement
Ebadian, M.A.; Dillion, J.; Moore, J.; Jones, K.
1998-01-01T23:59:59.000Z
Measurement of the physical properties (viscosity and density) of waste slurries is critical in evaluating transport parameters to ensure turbulent flow through transport pipes. The environment for measurement and sensor exposure is extremely harsh; therefore, reliability and ruggedness are critical in the sensor design. Two different viscometer techniques are being investigated in this study, based on: magnetostrictive pulse generated acoustic waves; and an oscillating cylinder. Prototype sensors have been built and tested which are based on both techniques. A base capability instrumentation system has been designed, constructed, and tested which incorporates both of these sensors. It requires manual data acquisition and off-line calculation. A broad range of viscous media has been tested using this system. Extensive test results appear in this report. The concept for each technique has been validated by these test results. This base capability system will need to be refined further before it is appropriate for field tests. The mass of the oscillating system structure will need to be reduced. A robust acoustic probe assembly will need to be developed. In addition, in March 1997 it was made known for the first time that the requirement was for a deliverable automated viscosity instrumentation system. Since then such a system has been designed, and the hardware has been constructed so that the automated concept can be proved. The rest of the hardware, which interfaced to a computer, has also been constructed and tested as far as possible. However, for both techniques the computer software for automated data acquisition, calculation, and logging had not been completed before funding and time ran out.
Dynamic Particle Coupling for GPU-based Fluid Simulation
Blanz, Volker
-vi Żj 2 W( Pi -Pj ,h). Here pj = k( Żj - 0) is the pressure with gas constant k and rest density 0 for modeling dynamic particle coupling solely based on individual particle contributions. This technique does and µ is the fluid viscosity constant. To model the surface tension, M¨uller et.al. [MCG03] use the so
Fundamentals of Engineering (FE) Exam Fluid Mechanics Review
Provancher, William
and mechanical energy balance B. Hydrostatic pressure C. Dimensionless numbers (e.g., Reynolds Number) D. Laminar, Friction Loss, and Pipe Flow Momentum and Drag #12;#12;Viscosity § Shear stress (): force required to slide;#12;Pressure §Hydrostatic pressure: pressure of fluid on immersed object or container walls §Pressure = force
Relation between viscosity and stability for heavy oil emulsions
Ye, Sherry Qianwen
1998-01-01T23:59:59.000Z
to relate the relative stability to the surfactant concentration. The parameters are yield stress (10) and high shear limit viscosity (n.). Based on the Pal and Rhode viscosity equation derived for both Newtonian and non-Newtonian emulsions, the parameter N...
Experimental investigations of the viscosity of nanofluids at low temperatures
Paris-Sud XI, Université de
Experimental investigations of the viscosity of nanofluids at low temperatures Bahadir Aladag a nanofluids at low concentration and low temperatures are experimentally investigated. The viscosity data were stress ramp. CNT and Al2O3 water based nanofluids exhibited hysteresis behaviour when the stress
Type II Migration: Varying Planet Mass and Disc Viscosity
Richard G. Edgar
2008-07-03T23:59:59.000Z
This paper continues an earlier study of giant planet migration, examining the effect of planet mass and disc viscosity on the migration rate. We find that the migration rate of a gap-opening planet varies systematically with the planet's mass, as predicted in our earlier work. However, the variation with disc viscosity appears to be much weaker than expected.
1 Visco-plastic rheology 1.1 Effective viscosity
Cerveny, Vlastislav
1 Visco-plastic rheology 1.1 Effective viscosity Rheology specifies the relationship between viscosity eff, = 2eff , (2) which includes viscous and plastic components, 1 eff = 1 visc + 1 plast . (3) Also the strain rate tensor can be split into viscous and plastic part, = visc + plast , (4) where
Extensional viscosity of copper nanowire suspensions in an aqueous polymer solution
Amarin G. McDonnell; Naveen N. Jason; Leslie Y. Yeo; James R. Friend; Wenlong Cheng; Ranganathan Prabhakar
2015-08-05T23:59:59.000Z
Suspensions of copper nanowires are emerging as new electronic inks for next-generation flexible electronics. Using a novel surface acoustic wave driven extensional flow technique we are able to perform currently lacking analysis of these suspensions and their complex buffer. We observe extensional viscosities from 3 mPa$\\cdot$s (1 mPa$\\cdot$s shear viscosity) to 37.2 Pa$\\cdot$s via changes in the suspension concentration, thus capturing low viscosities that have been historically very challenging to measure. These changes equate to an increase in the relative extensional viscosity of nearly 12,200 times at a volume fraction of just 0.027. We also find that interactions between the wires and the necessary polymer additive affect the rheology strongly. Polymer-induced elasticity shows a reduction as the buffer relaxation time falls from 819 to 59 $\\mu$s above a critical particle concentration. The results and technique presented here should aid in the future formulation of these promising nanowire suspensions and their efficient application as inks and coatings.
Notes 09. Fluid inertia and turbulence in fluid film bearings
San Andres, Luis
2009-01-01T23:59:59.000Z
inertia effects. Current applications of importance include operation with water and lubricant mixtures, liquid metals in the nuclear industry, and cryogenic fluids in space turbopumps. Large clearance elements such as squeeze film dampers and annular.... Use the program to observe the effects of fluid inertia in the pressure field (shifting and increase/decrease) and the resulting forces. In addition, derive conclusions from the effects of the Gumbel cavitation condition on the fluid film forces...
Yu, Xinwei
Oct. 1 0 Viscosity Solutions In this lecture we take a glimpse of the viscosity solution theory "viscosity solutions", and a quite complete regularity theory which paral- lels those we have seen has been a few example of the equations that can be dealt with using the idea of viscosity solutions. Example 1
Is there a "most perfect fluid" consistent with quantum field theory?
Thomas D. Cohen
2007-03-05T23:59:59.000Z
It was recently conjectured that the ratio of the shear viscosity to entropy density, $ \\eta/ s$, for any fluid always exceeds $\\hbar/(4 \\pi k_B)$. This conjecture was motivated by quantum field theoretic results obtained via the AdS/CFT correspondence and from empirical data with real fluids. A theoretical counterexample to this bound can be constructed from a nonrelativistic gas by increasing the number of species in the fluid while keeping the dynamics essentially independent of the species type. The question of whether the underlying structure of relativistic quantum field theory generically inhibits the realization of such a system and thereby preserves the possibility of a universal bound is considered here. Using rather conservative assumptions, it is shown here that a metastable gas of heavy mesons in a particular controlled regime of QCD provides a realization of the counterexample and is consistent with a well-defined underlying relativistic quantum field theory. Thus, quantum field theory appears to impose no lower bound on $\\eta/s$, at least for metastable fluids.
Soto, Enrique
2013-01-01T23:59:59.000Z
This fluid dynamics video is an entry for the Gallery of Fluid Motion for the 66th Annual Meeting of the Fluid Dynamics Division of the American Physical Society. We show the curious behaviour of a light ball interacting with a liquid jet. For certain conditions, a ball can be suspended into a slightly inclined liquid jet. We studied this phenomenon using a high speed camera. The visualizations show that the object can be `juggled' for a variety of flow conditions. A simple calculation showed that the ball remains at a stable position due to a Bernoulli-like effect. The phenomenon is very stable and easy to reproduce.
A note on the meaning of mixture viscosity using the classical continuum theories of mixtures
Massoudi, Mehrdad
2008-07-01T23:59:59.000Z
In this paper we provide a brief review of the basic equations for the flow of two linearly viscous fluids using the mixture theory equations given in Atkin and Craine [R.J. Atkin, R.E. Craine, Continuum theories of mixtures: applications, J. Inst. Math. Appl. 17 (1976) 153; R.J. Atkin, R.E. Craine, Continuum theories of mixtures: basic theory and historical development, Quart. J. Mech. Appl. Math. 29 (1976) 290]. We then look at certain principles (or more accurately assumptions) due to Truesdell [C. Truesdell, Sulle basi della thermomeccanica, Rand Lincei, Series 8 22 (1957) 33–38, and 158–166] and Adkins [J.E. Adkins, Non-linear diffusion, 1. Diffusion and flow of mixtures of fluids, Philos. Trans. Roy. Soc. London A 255 (1963) 607–633; J.E. Adkins, Non-linear diffusion, 2. Constitutive equations for mixtures of isotropic fluids, Philos. Trans. Roy. Soc. London A 255 (1963) 635–648] and show that if the ‘assumption of the limiting cases’ of Adkins is to hold, then a very specific structure on the material properties of the two fluids has to be imposed. This new hypothesis provides one such condition for this requirement. An attempt is made to derive a relationship for the mixture viscosity using these ideas.
Baled, Hseen O.; Tapriyal, Deepak; Morreale, Bryan D.; Soong, Yee; Gamwo, Isaac; Krukonis, Val; Bamgbade, Babatunde A.; Wu, Yue; McHugh, Mark A.; Burgess, Ward A.; M Enick, Robert M.
2013-10-01T23:59:59.000Z
DuPont’s perfluoropolyether oil Krytox® GPL 102 is a promising candidate for the high-temperature, high-pressure Deepwater viscosity standard (DVS). The preferred DVS is a thermally stable liquid that exhibits a viscosity of roughly 20 mPa?s at 533 K and 241 MPa; a viscosity value representative of light oils found in ultra-deep formations beneath the deep waters of the Gulf of Mexico. A windowed rolling-ball viscometer designed by our team is used to determine the Krytox® GPL 102 viscosity at pressures to 245 MPa and temperatures of 311 K, 372 K, and 533 K. At 533 K and 243 MPa, the Krytox® GPL 102 viscosity is (27.2±1.3)mPa?s . The rolling-ball viscometer viscosity results for Krytox® GPL 102 are correlated with an empirical 10-parameter surface fitting function that yields an MAPD of 3.9 %. A Couette rheometer is also used to measure the Krytox® GPL 102 viscosity, yielding a value of (26.2±1)mPa?s at 533 K and 241 MPa. The results of this exploratory study suggest that Krytox® GPL 102 is a promising candidate for the DVS, primarily because this fluoroether oil is thermally stable and exhibits a viscosity closer to the targeted value of 20 mPa ? s at 533 K and 241 MPa than any other fluid reported to date. Nonetheless, further studies must be conducted by other researcher groups using various types of viscometers and rheometers on samples of Krytox GPL® 102 from the same lot to further establish the properties of Krytox GPL® 102.
VISCOSITY OF AQUEOUS SODIUM CHLORIDE SOLUTIONS FROM 0 - 150oC
Ozbek, H.
2010-01-01T23:59:59.000Z
A. , Fabuss, B.M. , "Viscosities of Binary Aqueous Solutionsof Pressure on the Viscosity of Aqueous NaCl Solutions inF.A. , Kestin, J. , "The Viscosity of NaCl and KCl Solutions
New York at Stoney Brook, State University of
Chaos, Transport, and Mesh Convergence for Fluid Mixing # H. Lim, 1 Y. Yu, 1 J. Glimm, 1, 2 X in Fig. 1. The fluid interface, at late time, is volume filling. The transport coe#cients (viscosity) Chaotic mixing of distinct fluids produces a convoluted structure to the inter face separating
Viscosity prescription for gravitationally unstable accretion disks
Rafikov, Roman R
2015-01-01T23:59:59.000Z
Gravitationally unstable accretion disks emerge in a variety of astrophysical contexts - giant planet formation, FU Orioni outbursts, feeding of AGNs, and the origin of Pop III stars. When a gravitationally unstable disk is unable to cool rapidly it settles into a quasi-stationary, fluctuating gravitoturbulent state, in which its Toomre Q remains close to a constant value Q_0~1. Here we develop an analytical formalism describing the evolution of such a disk, which is based on the assumptions of Q=Q_0 and local thermal equilibrium. Our approach works in the presence of additional sources of angular momentum transport (e.g. MRI), as well as external irradiation. Thermal balance dictates a unique value of the gravitoturbulent stress \\alpha_{gt} driving disk evolution, which is a function of the local surface density and angular frequency. We compare this approach with other commonly used gravitoturbulent viscosity prescriptions, which specify the explicit dependence of stress \\alpha_{gt} on Toomre Q in an ad hoc...
A Brief Review of Viscosity Models for Slag in Coal Gasification
Massoudi, Mehrdad; Wang, Ping
2011-11-01T23:59:59.000Z
Many researchers have defined the phenomenon of 'slagging' as the deposition of ash in the radiative section of a boiler, while 'fouling' refers to the deposition of ash in the convective-pass region. Among the important parameters affecting ash deposition that need to be studied are ash chemistry, its transport, deposit growth, and strength development; removability of the ash deposit; heat transfer mechanisms; and the mode of operation for boilers. The heat transfer at the walls of a combustor depends on many parameters including ash deposition. This depends on the processes or parameters controlling the impact efficiency and the sticking efficiency. For a slagging combustor or furnace, however, the temperatures are so high that much of the coal particles are melted and the molten layer, in turn, captures more particles as it flows. The main problems with ash deposition are reduced heat transfer in the boiler and corrosion of the tubes. Common ways of dealing with these issues are soot blowing and wall blowing on a routine basis; however, unexpected or uncontrolled depositions can also complicate the situation, and there are always locations inaccessible to the use of such techniques. Studies have indicated that slag viscosity must be within a certain range of temperatures for tapping and the membrane wall to be accessible, for example, between 1300 C and 1500 C, the viscosity is approximately 25 Pa {center_dot} s. As the operating temperature decreases, the slag cools and solid crystals begin to form. In such cases the slag should be regarded as a non-Newtonian suspension, consisting of liquid silicate and crystals. A better understanding of the rheological properties of the slag, such as yield stress and shear-thinning, are critical in determining the optimum operating conditions. To develop an accurate heat transfer model in any type of coal combustion or gasification process, the heat transfer and to some extent the rheological properties of ash and slag, especially in high-temperature environments need to be understood and properly modeled. The viscosity of slag and the thermal conductivity of ash deposits are among two of the most important constitutive parameters that need to be studied. The accurate formulation or representations of the (transport) properties of coal (and biomass for co-firing cases) present a special challenge of modeling efforts in computational fluid dynamics applications. In this report, we first provide a brief review of the various approaches taken by different researchers in formulating or obtaining a slag viscosity model. In general, these models are based on experiments. Since slag behaves as a non-linear fluid, we discuss the constitutive modeling of slag and the important parameters that must be studied.
Bulk viscosity, chemical equilibration and flow at RHIC
Thomas Schaefer; Kevin Dusling
2012-10-15T23:59:59.000Z
We study the effects of bulk viscosity on p_T spectra and elliptic flow in heavy ion collisions at RHIC. We argue that direct effect of the bulk viscosity on the evolution of the velocity field is small, but corrections to the freezeout distributions can be significant. These effects are dominated by chemical non-equilibration in the hadronic phase. We show that a non-zero bulk viscosity in the range $\\zeta/s \\lsim 0.05$ improves the description of spectra and flow at RHIC.
6. Fluid mechanics: fluid statics; fluid dynamics
Zevenhoven, Ron
Figure Pressure (a scalar!) is defined as surface force / area, for example pb = Fb / (d·w) = p @ z = z1 Picture: KJ05 Fluid volume h·d·w with density and mass m = h·d·w· z = z1 In engineering forces Fn+ Fs = 0 or - py·h·w + py·h·w = 0 py = 0 Similarly Fw+ Fe= 0 gives px = 0, There are three
Cosmological fluctuations of a random field and radiation fluid
Bastero-Gil, Mar [Departamento de Física Teórica y del Cosmos, Campus de Fuentenueva, Universidad de Granada, Granada, 18071 (Spain); Berera, Arjun [SUPA, School of Physics and Astronomy, University of Edinburgh, Edinburgh, EH9 3JZ (United Kingdom); Moss, Ian G. [School of Mathematics and Statistics, Newcastlle University, Newcastle upon Tyne, NE1 7RU (United Kingdom); Ramos, Rudnei O., E-mail: mbg@ugr.es, E-mail: ab@ph.ed.ac.uk, E-mail: ian.moss@ncl.ac.uk, E-mail: rudnei@uerj.br [Departamento de Física Teórica, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, RJ, 20550-013 Brazil (Brazil)
2014-05-01T23:59:59.000Z
A generalization of the random fluid hydrodynamic fluctuation theory due to Landau and Lifshitz is applied to describe cosmological fluctuations in systems with radiation and scalar fields. The viscous pressures, parametrized in terms of the bulk and shear viscosity coefficients, and the respective random fluctuations in the radiation fluid are combined with the stochastic and dissipative scalar evolution equation. This results in a complete set of equations describing the perturbations in both scalar and radiation fluids. These derived equations are then studied, as an example, in the context of warm inflation. Similar treatments can be done for other cosmological early universe scenarios involving thermal or statistical fluctuations.
Viscous quark-gluon plasma model through fluid QCD approach
Djun, T. P., E-mail: tpdjun@teori.fisika.lipi.go.id [Graduate Study in Material Science, University of Indonesia, Kampus UI Salemba, Jakarta 10430, Indonesia and Group for Theoretical and Computational Physics, Research Center for Physics, Indonesian Institute of Sciences, Kompleks Puspiptek Serpong, T (Indonesia); Soegijono, B.; Mart, T. [Graduate Study in Material Science, University of Indonesia, Kampus UI Salemba, Jakarta 10430, Indonesia and Department of Physics, University of Indonesia, Kampus UI Depok, Depok 16424 (Indonesia); Handoko, L. T., E-mail: Handoko@teorifisika.lipi.go.id, E-mail: Laksana.tri.handoko@lipi.go.id [Group for Theoretical and Computational Physics, Research Center for Physics, Indonesian Institute of Sciences, Kompleks Puspiptek Serpong, Tangerang 15310, Indonesia and Research Center for Informatics, Indonesia Institute of Sciences, Kompleks LIPI (Indonesia)
2014-09-25T23:59:59.000Z
A Lagrangian density for viscous quark-gluon plasma has been constructed within the fluid-like QCD framework. Gauge symmetry is preserved for all terms inside the Lagrangian, except for the viscous term. The transition mechanism from point particle field to fluid field, and vice versa, are discussed. The energy momentum tensor that is relevant to the gluonic plasma having the nature of fluid bulk of gluon sea is derived within the model. By imposing conservation law in the energy momentum tensor, shear viscosity appears as extractable from the equation.
Maruyama, Shigeo
1 Temperature dependent thermal conductivity increase of aqueous nanofluid with single walled nanofluids, which we then thoroughly characterized by microscopic and spectroscopic methods. Electrical of the nanofluid was also found to increase with increasing temperature. Viscosity of the nanofluids showed
Method for controlling the viscosity of siloxane oils
Carey, A.A.; Shor, J.T.
1984-09-12T23:59:59.000Z
This invention relates to a method of controlling the viscosity of siloxane oils in the presence of lead by adding a small amount of a dione such as p-benzoquinone or 2,3-butanedione.
Method for controlling the viscosity of siloxane oils
Carey, A. Andrew (Lenoir City, TN); Shor, Joel T. (Oak Ridge, TN)
1985-01-01T23:59:59.000Z
This invention relates to a method of controlling the viscosity of siloxane oils in the presence of lead by adding a small amount of a dione such as p-benzoquinone or 2,3-butanedione.
Hall viscosity and angular momentum in gapless holographic models
Liu, Hong
We use the holographic approach to compare the Hall viscosity ?[subscript H] and the angular momentum density J in gapless systems in 2 + 1 dimensions at finite temperature. We start with a conformal fixed point and turn ...
Transition between fragmentation and permeable outgassing of low viscosity magmas
Manga, Michael
Transition between fragmentation and permeable outgassing of low viscosity magmas Atsuko Namiki a; fragmentation; decompression; permeability; outgassing; basaltic magma; fire fountain 1. Introduction into discrete pieces (fragmentation) and the rate at which gases escape from the rising magma (outgassing
Viscosity and boost invariance at RHIC and LHC
Piotr Bozek
2008-03-31T23:59:59.000Z
We consider the longitudinal hydrodynamic evolution of the fireball created in a relativistic heavy-ion collision. Nonzero shear viscosity reduces the colling rate of the system and hinders the acceleration of the longitudinal flow. As a consequence, the initial energy density needed to reproduce the experimental data at RHIC energies is significantly reduced. At LHC energies, we expect that shear viscosity helps to conserve a Bjorken plateau in the rapidity distributions during the expansion.
Bulk viscosity and the conformal anomaly in the pion gas
D. Fernandez-Fraile; A. Gomez Nicola
2009-02-27T23:59:59.000Z
We calculate the bulk viscosity of the massive pion gas within Unitarized Chiral Perturbation Theory. We obtain a low temperature peak arising from explicit conformal breaking due to the pion mass and another peak near the critical temperature, dominated by the conformal anomaly through gluon condensate terms. The correlation between bulk viscosity and conformal breaking supports a recent QCD proposal. We discuss the role of resonances, heavier states and large-$N_c$ counting.
Vanishing viscosity and the accumulation of vorticity on the boundary
James P. Kelliher
2008-05-15T23:59:59.000Z
We say that the vanishing viscosity limit holds in the classical sense if the velocity for a solution to the Navier-Stokes equations converges in the energy norm uniformly in time to the velocity for a solution to the Euler equations. We prove, for a bounded domain in dimension 2 or higher, that the vanishing viscosity limit holds in the classical sense if and only if a vortex sheet forms on the boundary.
Motility induced changes in viscosity of suspensions of swimming microbes in extensional flows
Amarin G. McDonnell; Tilvawala C. Gopesh; Jennifer Lo; Moira O'Bryan; Leslie Y. Yeo; James R. Friend; Ranganathan Prabhakar
2015-02-23T23:59:59.000Z
Suspensions of motile cells are model systems for understanding the unique mechanical properties of living materials which often consist of ensembles of self-propelled particles. We present here a quantitative comparison of theory against experiment for the rheology of such suspensions. The influence of motility on viscosities of cell suspensions is studied using a novel acoustically-driven microfluidic capillary-breakup extensional rheometer. Motility increases the extensional viscosity of suspensions of algal pullers, but decreases it in the case of bacterial or sperm pushers. A recent model [Saintillan, Phys. Rev. E, 2010, 81:56307] for dilute active suspensions is extended to obtain predictions for higher concentrations, after independently obtaining parameters such as swimming speeds and diffusivities. We show that details of body and flagellar shape can significantly determine macroscale rheological behaviour.
Use of ammonia to reduce the viscosity of bottoms streams produced in hydroconversion processes
Zaczepinski, Sioma (Houston, TX); Billimoria, Rustom M. (Houston, TX); Tao, Frank (Baytown, TX); Lington, Christopher G. (Houston, TX); Plumlee, Karl W. (Baytown, TX)
1984-01-01T23:59:59.000Z
Coal, petroleum residuum and similar carbonaceous feed materials are subjected to hydroconversion in the presence of molecular hydrogen to produce a hydroconversion effluent which is then subjected to one or more separation steps to remove lower molecular weight liquids and produce a heavy bottoms stream containing high molecular weight liquids and unconverted carbonaceous material. The viscosity of the bottoms streams produced in the separation step or steps is prevented from increasing rapidly by treating the feed to the separation step or steps with ammonia gas prior to or during the separation step or steps. The viscosity of the heavy bottoms stream produced in the final separation step is also controlled by treating these bottoms with ammonia gas. In a preferred embodiment of the invention, the effluent from the hydroconversion reactor is subjected to an atmospheric distillation followed by a vacuum distillation and the feeds to these distillations are contacted with ammonia during the distillations.
Mantle Dynamics in Super-Earths: Post-Perovskite Rheology and Self-Regulation of Viscosity
Tackley, Paul J; Brodholt, John P; Dobson, David P; Valencia, Diana
2012-01-01T23:59:59.000Z
Simple scalings suggest that super-Earths are more likely than an equivalent Earth-sized planet to be undergoing plate tectonics. Generally, viscosity and thermal conductivity increase with pressure while thermal expansivity decreases, resulting in lower convective vigor in the deep mantle. According to conventional thinking, this might result in no convection in a super-Earth's deep mantle. Here we evaluate this. First, we here extend the density functional theory (DFT) calculations of post-perovskite activation enthalpy of to a pressure of 1 TPa. The activation volume for diffusion creep becomes very low at very high pressure, but nevertheless for the largest super-Earths the viscosity along an adiabat may approach 1030 Pa s in the deep mantle. Second, we use these calculated values in numerical simulations of mantle convection and lithosphere dynamics of planets with up to ten Earth masses. The models assume a compressible mantle including depth-dependence of material properties and plastic yielding induce...
Viscosity of liquid He-4 and quantum of circulation: Why and how are they related?
V. S. L'vov; L. Skrbek
2011-02-16T23:59:59.000Z
The relationship between the apparently unrelated physical quantities -- kinematic viscosity of liquid He-4, $\
The viscosity structure of the D00 layer of the Earth's mantle inferred
The viscosity structure of the D00 layer of the Earth's mantle inferred from the analysis layer Coremantle boundary Viscosity Maxwell body a b s t r a c t The viscosity structure of the D00-diurnal to 18.6 years tidal deformations combined with model viscositydepth profiles corresponding to a range
Viscosity of semi-dilute polymer solutions M. Adam and M. Delsanti
Paris-Sud XI, Université de
549 Viscosity of semi-dilute polymer solutions M. Adam and M. Delsanti Laboratoire Léon viscosity measurements on semi-dilute solutions (c* c 10 %). The viscosity variation is independent to the solvent viscosity. With concentration, the following variations were observed : 2014 for PIB-toluene, ~r
Simulating Fluids Exhibiting Microstructure
Title: Simulating Fluids Exhibiting Microstructure Speaker: Noel J. Walkington, ... fluids containing elastic particles, and polymer fluids, all exhibit non-trivial ...
The effects of plasma diffusion and viscosity on turbulent instability growth
Haines, Brian M., E-mail: bmhaines@lanl.gov; Vold, Erik L.; Molvig, Kim; Aldrich, Charles; Rauenzahn, Rick [Los Alamos National Laboratory, MS T087, Los Alamos, New Mexico 87545 (United States)
2014-09-15T23:59:59.000Z
We perform two-dimensional simulations of strongly–driven compressible Rayleigh–Taylor and Kelvin–Helmholtz instabilities with and without plasma transport phenomena, modeling plasma species diffusion, and plasma viscosity in order to determine their effects on the growth of the hydrodynamic instabilities. Simulations are performed in hydrodynamically similar boxes of varying sizes, ranging from 1 ?m to 1?cm in order to determine the scale at which plasma effects become important. Our results suggest that these plasma effects become noticeable when the box size is approximately 100 ?m, they become significant in the 10 ?m box, and dominate when the box size is 1 ?m. Results suggest that plasma transport may be important at scales and conditions relevant to inertial confinement fusion, and that a plasma fluid model is capable of representing some of the kinetic transport effects.
Pore fluid effects on seismic velocity in anisotropic rocks
Mukerji, T.; Mavko, G. (Stanford Univ., CA (United States). Dept. of Geophysics)
1994-02-01T23:59:59.000Z
A simple new technique predicts the high- and low-frequency saturated velocities in anisotropic rocks entirely in terms of measurable dry rock properties without the need for idealized crack geometries. Measurements of dry velocity versus pressure and porosity versus pressure contain all of the necessary information for predicting the frequency-dependent effects of fluid saturation. Furthermore, these measurements automatically incorporate all pore interaction, so there is no limitation to low crack density. The velocities are found to depend on five key interrelated variables: frequency, the distribution of compliant crack-like porosity, the intrinsic or noncrack anisotropy, fluid viscosity and compressibility, and effective pressure. The sensitivity of velocities to saturation is generally greater at high frequencies than low frequencies. The magnitude of the differences from dry to saturated and from low frequency to high frequency is determined by the compliant or crack-like porosity. Predictions of saturated velocities based on dry data for sandstone and granite show that compressional velocities generally increase with saturation and with frequency. However, the degree of compressional wave anisotropy may either increase or decrease upon saturation depending on the crack distribution, the effective pressure, and the frequency at which the measurements are made. Shear-wave velocities can either increase or decrease with saturation, and the degree of anisotropy depends on the microstructure, pressure, and frequency. Consequently great care must be taken when interpreting observed velocity anisotropy for measurements at low frequencies, typical of in situ observations, will generally be different from those at high frequencies, typical of the laboratory.
Viscosity Determination of Molten Ash from Low-Grade US Coals
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Zhu, Jingxi [National Energy Technology Laboratory (NETL), Pittsburgh, PA, and Morgantown, WV (United States); URS Corp., Albany, OR (United States); Nakano, Jinichiro [National Energy Technology Laboratory (NETL), Pittsburgh, PA, and Morgantown, WV (United States); URS Corp., Albany, OR (United States); Kaneko, Tetsuya Kenneth [National Energy Technology Laboratory (NETL), Pittsburgh, PA, and Morgantown, WV (United States); Carnegie Mellon Univ., Pittsburgh, PA (United States); Mu, Haoyuan [Carnegie Mellon Univ., Pittsburgh, PA (United States); Bennett, James P. [National Energy Technology Laboratory (NETL), Pittsburgh, PA, and Morgantown, WV (United States); Kwong, Kyei-Sing [National Energy Technology Laboratory (NETL), Pittsburgh, PA, and Morgantown, WV (United States); Rozelle, Peter [US Dept. of Energy, Washington, DC (United States). Office of Clean Energy Systems; Sridhar, Seetharaman [National Energy Technology Laboratory (NETL), Pittsburgh, PA, and Morgantown, WV (United States); Carnegie Mellon Univ., Pittsburgh, PA (United States)
2011-10-01T23:59:59.000Z
In entrained slagging gasifiers, the fluidity of the molten ash is a critical factor for process control since it affects slag formation, the capture of inorganic constituents, refractory wear, and slag drainage along the gasification chamber walls. The use of western coal, or mixtures of eastern and western coals as gasifier feedstock, is likely to occur as western coals become available and technological issues that hinder their use are being resolved. In the present work, the viscosity of synthetic slags with ash chemistries simulating the western U.S. coals, was experimentally measured at a Po2?=?10- 8 atm in the temperature range of 1773–1573 K (1500–1300 °C) using a rotating-bob viscometer. Alumina spindles and containment crucibles of both alumina and zirconia were used. Crystallization studies of this slag using a confocal scanning laser microscope found that a (Mg,Fe)Al2O4-based spinel precipitated at temperatures below 1723 K (1450 °C), and this agreed with FactSage equilibrium phase prediction. The same spinels were observed in the post-viscometry experiment slags when ZrO2 crucibles were used and assumed to be in equilibrium with the slag at the higher temperatures. Zirconia dissolution resulted in a slight increase in the solid fraction present in slags at lower temperatures, compared to spinel fraction. Crystal precipitation changed the apparent activation energy and required a longer stabilization times for viscosity measurements. The viscosity results were used in predictive equations based on Veytsman and Einstein's models, with critical nucleation temperatures and the solid fraction calculated with FactSage. In the simulated eastern/western coal feedstock blends based on ash compositions, the fractions of the solid precipitates were also calculated using the thermodynamic program FactSage for each blend composition, and the plastic viscosity of each eastern/western coal slag blend was predicted using Veytsman's model and compared to available experimental data.
Viscosity Determination of Molten Ash from Low-Grade US Coals
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Zhu, Jingxi; Nakano, Jinichiro; Kaneko, Tetsuya Kenneth; Mu, Haoyuan; Bennett, James P.; Kwong, Kyei-Sing; Rozelle, Peter; Sridhar, Seetharaman
2011-10-01T23:59:59.000Z
In entrained slagging gasifiers, the fluidity of the molten ash is a critical factor for process control since it affects slag formation, the capture of inorganic constituents, refractory wear, and slag drainage along the gasification chamber walls. The use of western coal, or mixtures of eastern and western coals as gasifier feedstock, is likely to occur as western coals become available and technological issues that hinder their use are being resolved. In the present work, the viscosity of synthetic slags with ash chemistries simulating the western U.S. coals, was experimentally measured at a Po2?=?10- 8 atm in the temperature rangemore »of 1773–1573 K (1500–1300 °C) using a rotating-bob viscometer. Alumina spindles and containment crucibles of both alumina and zirconia were used. Crystallization studies of this slag using a confocal scanning laser microscope found that a (Mg,Fe)Al2O4-based spinel precipitated at temperatures below 1723 K (1450 °C), and this agreed with FactSage equilibrium phase prediction. The same spinels were observed in the post-viscometry experiment slags when ZrO2 crucibles were used and assumed to be in equilibrium with the slag at the higher temperatures. Zirconia dissolution resulted in a slight increase in the solid fraction present in slags at lower temperatures, compared to spinel fraction. Crystal precipitation changed the apparent activation energy and required a longer stabilization times for viscosity measurements. The viscosity results were used in predictive equations based on Veytsman and Einstein's models, with critical nucleation temperatures and the solid fraction calculated with FactSage. In the simulated eastern/western coal feedstock blends based on ash compositions, the fractions of the solid precipitates were also calculated using the thermodynamic program FactSage for each blend composition, and the plastic viscosity of each eastern/western coal slag blend was predicted using Veytsman's model and compared to available experimental data.« less
Dark goo: Bulk viscosity as an alternative to dark energy
Jean-Sebastien Gagnon; Julien Lesgourgues
2011-09-16T23:59:59.000Z
We present a simple (microscopic) model in which bulk viscosity plays a role in explaining the present acceleration of the universe. The effect of bulk viscosity on the Friedmann equations is to turn the pressure into an "effective" pressure containing the bulk viscosity. For a sufficiently large bulk viscosity, the effective pressure becomes negative and could mimic a dark energy equation of state. Our microscopic model includes self-interacting spin-zero particles (for which the bulk viscosity is known) that are added to the usual energy content of the universe. We study both background equations and linear perturbations in this model. We show that a dark energy behavior is obtained for reasonable values of the two parameters of the model (i.e. the mass and coupling of the spin-zero particles) and that linear perturbations are well-behaved. There is no apparent fine tuning involved. We also discuss the conditions under which hydrodynamics holds, in particular that the spin-zero particles must be in local equilibrium today for viscous effects to be important.
Dark goo: Bulk viscosity as an alternative to dark energy
Gagnon, Jean-Sebastien
2011-01-01T23:59:59.000Z
We present a simple (microscopic) model in which bulk viscosity plays a role in explaining the present acceleration of the universe. The effect of bulk viscosity on the Friedmann equations is to turn the pressure into an "effective" pressure containing the bulk viscosity. For a sufficiently large bulk viscosity, the effective pressure becomes negative and could mimic a dark energy equation of state. Our microscopic model includes self-interacting spin-zero particles (for which the bulk viscosity is known) that are added to the usual energy content of the universe. We study both background equations and linear perturbations in this model. We show that a dark energy behavior is obtained for reasonable values of the two parameters of the model (i.e. the mass and coupling of the spin-zero particles) and that linear perturbations are well-behaved. There is no apparent fine tuning involved. We also discuss the conditions under which hydrodynamics holds, in particular that the spin-zero particles must be in local eq...
Viscosity and scale invariance in the unitary Fermi gas
Tilman Enss; Rudolf Haussmann; Wilhelm Zwerger
2010-10-12T23:59:59.000Z
We compute the shear viscosity of the unitary Fermi gas above the superfluid transition temperature, using a diagrammatic technique that starts from the exact Kubo formula. The formalism obeys a Ward identity associated with scale invariance which guarantees that the bulk viscosity vanishes identically. For the shear viscosity, vertex corrections and the associated Aslamazov-Larkin contributions are shown to be crucial to reproduce the full Boltzmann equation result in the high-temperature, low fugacity limit. The frequency dependent shear viscosity $\\eta(\\omega)$ exhibits a Drude-like transport peak and a power-law tail at large frequencies which is proportional to the Tan contact. The weight in the transport peak is given by the equilibrium pressure, in agreement with a sum rule due to Taylor and Randeria. Near the superfluid transition the peak width is of the order of $0.5 T_F$, thus invalidating a quasiparticle description. The ratio $\\eta/s$ between the static shear viscosity and the entropy density exhibits a minimum near the superfluid transition temperature whose value is larger than the string theory bound $\\hbar/(4\\pi k_B)$ by a factor of about seven.
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
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:1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:5 TablesExports(Journal Article) |govInstrumentsmfrirt DocumentationSitesWeather6Environmental SecurityExtra-LargeBauerWorldwideFascinating Fluids
Wai, Chien M. (Moscow, ID); Laintz, Kenneth E. (Los Alamos, NM)
1999-01-01T23:59:59.000Z
A method of extracting metalloid and metal species from a solid or liquid material by exposing the material to a supercritical fluid solvent containing a chelating agent is described. The chelating agent forms chelates that are soluble in the supercritical fluid to allow removal of the species from the material. In preferred embodiments, the extraction solvent is supercritical carbon dioxide and the chelating agent is a fluorinated .beta.-diketone. In especially preferred embodiments the extraction solvent is supercritical carbon dioxide, and the chelating agent comprises a fluorinated .beta.-diketone and a trialkyl phosphate, or a fluorinated .beta.-diketone and a trialkylphosphine oxide. Although a trialkyl phosphate can extract lanthanides and actinides from acidic solutions, a binary mixture comprising a fluorinated .beta.-diketone and a trialkyl phosphate or a trialkylphosphine oxide tends to enhance the extraction efficiencies for actinides and lanthanides. The method provides an environmentally benign process for removing contaminants from industrial waste without using acids or biologically harmful solvents. The method is particularly useful for extracting actinides and lanthanides from acidic solutions. The chelate and supercritical fluid can be regenerated, and the contaminant species recovered, to provide an economic, efficient process.
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 $1/(4\\pi)$.
Shear Viscosity in the Post-quasistatic Approximation
C. Peralta; L. Rosales; B. Rodrí guez-Mueller; W. Barreto
2010-04-20T23:59:59.000Z
We apply the post-quasi--static approximation, an iterative method for the evolution of self-gravitating spheres of matter, to study the evolution of anisotropic non-adiabatic radiating and dissipative distributions in General Relativity. Dissipation is described by viscosity and free-streaming radiation, assuming an equation of state to model anisotropy induced by the shear viscosity. We match the interior solution, in non-comoving coordinates, with the Vaidya exterior solution. Two simple models are presented, based on the Schwarzschild and Tolman VI solutions, in the non--adiabatic and adiabatic limit. In both cases the eventual collapse or expansion of the distribution is mainly controlled by the anisotropy induced by the viscosity.
Post-glacial rebound and asthenosphere viscosity in Iceland
Sigmundsson, F. (Univ. of Colorado, Boulder (United States))
1991-06-01T23:59:59.000Z
During the Weichselian glaciation Iceland was covered with an ice cap which caused downward flexure of the Earth's surface. The post-glacial rebound in Iceland was very rapid, being completed in about 1,000 years. The length of this time interval constrains the maximum value of asthenosphere viscosity in Iceland to be 1 {times} 10{sup 19} Pa s or less. Further clarification of the ice retreat and uplift history may reveal lower viscosity. Current changes in the mass balance of Icelandic glaciers must lead to measurable elevation changes considering this low viscosity. Expected current elevation changes around the Vatnajoekull ice cap are of the order of 1 cm per year, due to mass balance change in this century.
Paris-Sud XI, Université de
with Sickle Cell Anemia and Recurrent Leg Ulcers Philippe Connes1,2,3* , Yann Lamarre1,2 , Marie-ŕ-Pitre, Guadeloupe Abstract Leg ulcer is a disabling complication in patients with sickle cell anemia (SCA Dehydrogenase Level in Patients with Sickle Cell Anemia and Recurrent Leg Ulcers. PLoS ONE 8(11): e79680. doi:10
The evolution of the shear viscosity away from unitarity
Gabriel Wlaz?owski; Wei Quan; Aurel Bulgac
2015-04-10T23:59:59.000Z
We present an it ab initio calculation of the shear viscosity as a function of interaction strength in a two-component unpolarized Fermi gas near unitary limit, within a finite temperature quantum Monte Carlo (QMC) framework and using the Kubo linear-response formalism. The shear viscosity decreases as we tune the interaction strength 1/ak_F from the Bardeen-Cooper-Schrieffer (BCS) side of the Feshbach resonance towards Bose-Einstein condensation (BEC) limit and it acquires the smallest value for 1/ak_F approx 0.4.
The evolution of the shear viscosity away from unitarity
Wlaz?owski, Gabriel; Bulgac, Aurel
2015-01-01T23:59:59.000Z
We present an it ab initio calculation of the shear viscosity as a function of interaction strength in a two-component unpolarized Fermi gas near unitary limit, within a finite temperature quantum Monte Carlo (QMC) framework and using the Kubo linear-response formalism. The shear viscosity decreases as we tune the interaction strength 1/ak_F from the Bardeen-Cooper-Schrieffer (BCS) side of the Feshbach resonance towards Bose-Einstein condensation (BEC) limit and it acquires the smallest value for 1/ak_F approx 0.4.
Bulk viscosity of strongly coupled plasmas with holographic duals
Steven S. Gubser; Silviu S. Pufu; Fabio D. Rocha
2008-06-02T23:59:59.000Z
We explain a method for computing the bulk viscosity of strongly coupled thermal plasmas dual to supergravity backgrounds supported by one scalar field. Whereas earlier investigations required the computation of the leading dissipative term in the dispersion relation for sound waves, our method requires only the leading frequency dependence of an appropriate Green's function in the low-frequency limit. With a scalar potential chosen to mimic the equation of state of QCD, we observe a slight violation of the lower bound on the ratio of the bulk and shear viscosities conjectured in arXiv:0708.3459.
Meiburg, Eckart H.
2008-01-01T23:59:59.000Z
by a miscible, less viscous one of lower density in a horizontal capillary tube is studied by means of Stokes displacements in capillary tubes S.H. Vanaparthy, E. Meiburg Department of Mechanical Engineering, University flow simulations. Both axisymmetric and three-dimensional simulations are conducted at Péclet numbers
A geological fingerprint of low-viscosity fault fluids mobilized during an earthquake
Brodsky, Emily E.; Rowe, Christie D.; Moore, J. Casey; Meneghini, Francesca
2009-01-01T23:59:59.000Z
Principles of Physical Sedimentology, George Allen andCalifornia, paper presented at Sedimentology of Gravels andcoarse-grained sediments, Sedimentology, 22(2), 157 – 204.
Ionizing Electron Incidents as an Efficient Way to Reduce Viscosity of Heavy Petroleum Fluids
Alfi, Masoud
2012-10-19T23:59:59.000Z
that high energy electron particles intensify the cracking of heavy hydrocarbons into lighter species. Moreover, irradiation is seen to limit any post-treatment reactions, providing products of higher stability. Depending on the characteristics...
Ionizing Electron Incidents as an Efficient Way to Reduce Viscosity of Heavy Petroleum Fluids
Alfi, Masoud
2012-10-19T23:59:59.000Z
that high energy electron particles intensify the cracking of heavy hydrocarbons into lighter species. Moreover, irradiation is seen to limit any post-treatment reactions, providing products of higher stability. Depending on the characteristics...
Rondon, Nolys Javier
2009-05-15T23:59:59.000Z
still remains a complex task due to the difficulty of designing a tool capable of measuring accurate rheological information under harsh operational conditions. This dissertation presents the evaluation of the performance of a novel device designed...
Effectiveness of continuous hot-fluid stimulation of high viscosity oil wells
Oetama, Teddy
1983-01-01T23:59:59.000Z
which represent the producing intervals were observed and plotted. Cycling Method Effects of Control Temperature on the Cycling Method Simulations were conducted for a system having 50 Ft formation thickness, 5 Ft perforated intervals, a kv/kh ratio... oil production rates, The more cycles that occur, the shorter the time to breakeven production. The closer the control temperature approaches the injection temperature of the system, the more cycles will occur. Too high a control temperature...
A. Gama Goicochea; M. A. Balderas Altamirano; R. Lopez-Esparza; M. A. Waldo; E. Perez
2015-06-20T23:59:59.000Z
The connection between fundamental interactions acting in molecules in a fluid and macroscopically measured properties, such as the viscosity between colloidal particles coated with polymers, is studied here. The role that hydrodynamic and Brownian forces play in colloidal dispersions is also discussed. It is argued that many body systems in which all these interactions take place can be accurately solved using computational simulation tools. One of those modern tools is the technique known as dissipative particle dynamics, which incorporates Brownian and hydrodynamic forces, as well as basic conservative interactions. A case study is reported, as an example of the applications of this technique, which consists of the prediction of the viscosity and friction between two opposing parallel surfaces covered with polymer chains, under the influence of a steady flow. This work is intended to serve as an introduction to the subject of colloidal dispersions and computer simulations, for last year undergraduate students and beginning graduate students who are interested in beginning research in soft matter systems. To that end, a computational code is included that students can use right away to study complex fluids in equilibrium.
Holographic fluids with perturbations of pressure and energy density at finite cutoff surface
Ya-Peng Hu; Yu Tian; Xiao-Ning Wu; Hongsheng Zhang
2015-07-30T23:59:59.000Z
We investigate the holographic fluids with perturbations of pressure and energy density at finite cutoff surface in the scenario of gravity/fluid correspondence. Perturbing the Schwarzschild-AdS black brane solution in the Einstein gravity, we explore the stress tensor of the holographic fluids with transport coefficients at a finite cutoff surface. We set a non-zero boundary condition for the derivative of $h(r)$ with respect to the radius direction $r$. We find that this boundary condition is critical to break the apparent degeneration of bulk viscosity and perturbation of the pressure for the dual fluid at the finite cutoff surface in our previous work (Phys.Lett. B732 (2014) 298). After this apparent degeneration broken, the bulk viscosity disappears, which is confirmed by the consideration of sound velocity.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Firlar, Emre; Ç?nar, Simge; Kashyap, Sanjay; Akinc, Mufit; Iowa State Univ., Ames, IA; Prozorov, Tanya
2015-05-21T23:59:59.000Z
Rheological behavior of aqueous suspensions containing nanometer-sized powders is of relevance to many branches of industry. Unusually high viscosities observed for suspensions of nanoparticles compared to those of micron size powders cannot be explained by current viscosity models. Formation of so-called hydration layer on alumina nanoparticles in water was hypothesized, but never observed experimentally. We report here on the direct visualization of aqueous suspensions of alumina with the fluid cell in situ. We observe the hydration layer formed over the particle aggregates and show that such hydrated aggregates constitute new particle assemblies and affect the flow behavior of the suspensions.more »We discuss how these hydrated nanoclusters alter the effective solid content and the viscosity of nanostructured suspensions. Our findings elucidate the source of high viscosity observed for nanoparticle suspensions and are of direct relevance to many industrial sectors including materials, food, cosmetics, pharmaceutical among others employing colloidal slurries with nanometer-scale particles.« less
Thermal convection with large viscosity variation in an enclosure with localized heating
Chu, T.Y.; Hickox, C.E.
1988-01-01T23:59:59.000Z
The present study is undertaken in order to gain an understanding of convective transport in a magma chamber. We have chosen to represent the chamber by an enclosure with localized heating from below. Results of both laboratory experiments and computer modeling are reported. The experimental apparatus consists of a transparent enclosure with a square planform. An electrically heated strip, with a width equal to one-fourth of the length of a side of the enclosure, is centered on the lower inside surface of the enclosure. For the experiments reported here, the top of the fluid layer is maintained at a constant temperature and the depth of the layer is equal to the width of the heated strip. The large viscosity variation characteristic of magma convection is simulated by using corn syrup as the working fluid. Measured velocity and temperature distribution as well as overall heat transfer rates are presented. The experiment is numerically simulated through use of a finite element computer program. Numerically predicted streamlines, isotherms, and velocity distributions are presented for the transverse vertical midplane of the enclosure. Good agreement is demonstrated between predictions and measurements. 23 refs., 8 figs., 2 tabs.
Shear viscosity of the $\\Phi^4$ theory from classical simulation
Homor, M M
2015-01-01T23:59:59.000Z
Shear viscosity of the classical $\\Phi^4$ theory is measured using classical microcanonical simulation. To calculate the Kubo formula, we measure the energy-momentum tensor correlation function, and apply the Green-Kubo relation. Being a classical theory, the results depend on the cutoff which should be chosen in the range of the temperature. Comparison with experimentally accessible systems is also performed.
Shear viscosity of boost invariant plasma at finite coupling
Alex Buchel
2008-03-04T23:59:59.000Z
We discuss string theory alpha' corrections in the dual description of the expanding boost invariant N=4 supersymmetric Yang-Mills plasma at strong coupling. We compute finite 't Hooft coupling corrections to the shear viscosity and find that it disagrees with the equilibrium correlation function computations. We comment on the possible source of the discrepancy.
Shear Viscosity to Entropy within a Parton Cascade
A. El; C. Greiner; Z. Xu
2007-06-28T23:59:59.000Z
The shear viscosity is calculated by means of the perturbative kinetic partonic cascade BAMPS with CGC initial conditons for various saturation momentum scale Q_s. eta/s ~ 0.15 stays approximately constant when going from RHIC to LHC.
Shear viscosity of the $?^4$ theory from classical simulation
M. M. Homor; A. Jakovac
2015-05-05T23:59:59.000Z
Shear viscosity of the classical $\\Phi^4$ theory is measured using classical microcanonical simulation. To calculate the Kubo formula, we measure the energy-momentum tensor correlation function, and apply the Green-Kubo relation. Being a classical theory, the results depend on the cutoff which should be chosen in the range of the temperature. Comparison with experimentally accessible systems is also performed.
Viscosity from elliptic flow: the path to precision
Ulrich W. Heinz; J. Scott Moreland; Huichao Song
2009-08-18T23:59:59.000Z
Using viscous relativistic hydrodynamics we show that systematic studies of the impact parameter dependence of the eccentricity scaled elliptic flow can distinguish between different models for the calculation of the initial source eccentricity. This removes the largest present uncertainty in the extraction of the specific viscosity of the matter created in relativistic heavy-ion collisions from precise elliptic flow measurements.
A Tensor Artificial Viscosity using a Mimetic Finite Difference Algorithm
Shashkov, Mikhail
internal energy and v in the velocity vector. If the hydrodynamics code is intended to solve problems in a hydrodynamics code are the conservation equa tions. For a Lagrangian code the equations of conservation of mass to derive forms of the mo mentum and energy equations for a nonorthogonal grid with the viscosity tensor
Author's personal copy Viscosity of magmatic liquids: A model
Russell, Kelly
for viscosity can also predict other transport properties including glass transition temperatures (Tg) and melt are effusive or explosive (Dingwell, 1996; Papale, 1999; Sparks, 2004). Other volatile components (CO2, Cl, Br assumes a common, high-T limit (A) for silicate melt viscosityand returns a value for this limit of -4
Viscosity of magmatic liquids: A model Daniele Giordano a,
Russell, Kelly
also predict other transport properties including glass transition temperatures (Tg) and melt fragility are effusive or explosive (Dingwell, 1996; Papale, 1999; Sparks, 2004). Other volatile components (CO2, Cl, Br-dependence of viscosity is accounted for by the VFTequation [log =A+B/(T(K)-C)]. The optimization assumes a common, high
Relativistic Viscous Fluid Description of Microscopic Black Hole Wind
J. I. Kapusta
2001-05-25T23:59:59.000Z
Microscopic black holes explode with their temperature varying inversely as their mass. Such explosions would lead to the highest temperatures in the present universe, all the way to the Planck energy. Whether or not a quasi-stationary shell of matter undergoing radial hydrodynamic expansion surrounds such black holes is been controversial. In this paper relativistic viscous fluid equations are applied to the problem. It is shown that a self-consistent picture emerges of a fluid just marginally kept in local thermal equilibrium; viscosity is a crucial element of the dynamics.
Memory Effects and Transport Coefficients for Non-Newtonian Fluids
T. Kodama; T. Koide
2008-12-22T23:59:59.000Z
We discuss the roles of viscosity in relativistic fluid dynamics from the point of view of memory effects. Depending on the type of quantity to which the memory effect is applied, different terms appear in higher order corrections. We show that when the memory effect applies on the extensive quantities, the hydrodynamic equations of motion become non-singular. We further discuss the question of memory effect in the derivation of transport coefficients from a microscopic theory. We generalize the application of the Green-Kubo-Nakano (GKN) to calculate transport coefficients in the framework of projection operator formalism, and derive the general formula when the fluid is non-Newtonian.
Chandrasekar, M.; Suresh, S. [Department of Mechanical Engineering, National Institute of Technology, Tiruchirappalli 620 015 (India); Chandra Bose, A. [Nanomaterials Laboratory, National Institute of Technology, Tiruchirappalli 620 015 (India)
2010-02-15T23:59:59.000Z
Experimental investigations and theoretical determination of effective thermal conductivity and viscosity of Al{sub 2}O{sub 3}/H{sub 2}O nanofluid are reported in this paper. The nanofluid was prepared by synthesizing Al{sub 2}O{sub 3} nanoparticles using microwave assisted chemical precipitation method, and then dispersing them in distilled water using a sonicator. Al{sub 2}O{sub 3}/water nanofluid with a nominal diameter of 43 nm at different volume concentrations (0.33-5%) at room temperature were used for the investigation. The thermal conductivity and viscosity of nanofluids are measured and it is found that the viscosity increase is substantially higher than the increase in thermal conductivity. Both the thermal conductivity and viscosity of nanofluids increase with the nanoparticle volume concentration. Theoretical models are developed to predict thermal conductivity and viscosity of nanofluids without resorting to the well established Maxwell and Einstein models, respectively. The proposed models show reasonably good agreement with our experimental results. (author)
Intermolecular potential parameters and combining rules determined from viscosity data
Bastien, Lucas A.J.; Price, Phillip N.; Brown, Nancy J.
2010-05-07T23:59:59.000Z
The Law of Corresponding States has been demonstrated for a number of pure substances and binary mixtures, and provides evidence that the transport properties viscosity and diffusion can be determined from a molecular shape function, often taken to be a Lennard-Jones 12-6 potential, that requires two scaling parameters: a well depth {var_epsilon}{sub ij} and a collision diameter {sigma}{sub ij}, both of which depend on the interacting species i and j. We obtain estimates for {var_epsilon}{sub ij} and {sigma}{sub ij} of interacting species by finding the values that provide the best fit to viscosity data for binary mixtures, and compare these to calculated parameters using several 'combining rules' that have been suggested for determining parameter values for binary collisions from parameter values that describe collisions of like molecules. Different combining rules give different values for {sigma}{sub ij} and {var_epsilon}{sub ij} and for some mixtures the differences between these values and the best-fit parameter values are rather large. There is a curve in ({var_epsilon}{sub ij}, {sigma}{sub ij}) space such that parameter values on the curve generate a calculated viscosity in good agreement with measurements for a pure gas or a binary mixture. The various combining rules produce couples of parameters {var_epsilon}{sub ij}, {sigma}{sub ij} that lie close to the curve and therefore generate predicted mixture viscosities in satisfactory agreement with experiment. Although the combining rules were found to underpredict the viscosity in most of the cases, Kong's rule was found to work better than the others, but none of the combining rules consistently yields parameter values near the best-fit values, suggesting that improved rules could be developed.
Phase-separation models for swimming enhancement in complex fluids
Man, Yi
2015-01-01T23:59:59.000Z
Swimming cells often have to self-propel through fluids displaying non-Newtonian rheology. While past theoretical work seems to indicate that stresses arising from complex fluids should systematically hinder low-Reynolds number locomotion, experimental observations suggest that locomotion enhancement is possible. In this paper we propose a physical mechanism for locomotion enhancement of microscopic swimmers in a complex fluid. It is based on the fact that micro-structured fluids will generically phase-separate near surfaces, leading to the presence of low-viscosity layers which promote slip and decrease viscous friction near the surface of the swimmer. We use two models to address the consequence of this phase separation: a nonzero apparent slip length for the fluid and then an explicit modeling of the change of viscosity in a thin layer near the swimmer. Considering two canonical setups for low-Reynolds number locomotion, namely the waving locomotion of a two-dimensional sheet and that of a three-dimensiona...
Thermophysical Properties of Fluids and Fluid Mixtures
Sengers, Jan V.; Anisimov, Mikhail A.
2004-05-03T23:59:59.000Z
The major goal of the project was to study the effect of critical fluctuations on the thermophysical properties and phase behavior of fluids and fluid mixtures. Long-range fluctuations appear because of the presence of critical phase transitions. A global theory of critical fluctuations was developed and applied to represent thermodynamic properties and transport properties of molecular fluids and fluid mixtures. In the second phase of the project, the theory was extended to deal with critical fluctuations in complex fluids such as polymer solutions and electrolyte solutions. The theoretical predictions have been confirmed by computer simulations and by light-scattering experiments. Fluctuations in fluids in nonequilibrium states have also been investigated.
T. S. Biro; E. Molnar
2012-01-28T23:59:59.000Z
We derive equations for fluid dynamics from a non-extensive Boltzmann transport equation consistent with Tsallis' non-extensive entropy formula. We evaluate transport coefficients employing the relaxation time approximation and investigate non-extensive effects in leading order dissipative phenomena at relativistic energies, like heat conductivity, shear and bulk viscosity.
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Dilley, Lorie
Fluid inclusion gas analysis for wells in various geothermal areas. Analyses used in developing fluid inclusion stratigraphy for wells and defining fluids across the geothermal fields. Each sample has mass spectrum counts for 180 chemical species.
Dilley, Lorie
2013-01-01T23:59:59.000Z
Fluid inclusion gas analysis for wells in various geothermal areas. Analyses used in developing fluid inclusion stratigraphy for wells and defining fluids across the geothermal fields. Each sample has mass spectrum counts for 180 chemical species.
Bulk viscosity of superfluid hyperon stars Mikhail E. Gusakov and Elena M. Kantor
Bulk viscosity of superfluid hyperon stars Mikhail E. Gusakov and Elena M. Kantor Ioffe Physical; published 14 October 2008) We calculate the bulk viscosity due to nonequilibrium weak processes bulk viscosity coefficients, with only three of them being independent. In addition, we correct
Viscosity and longest relaxation time of semi-dilute polymer solutions. I. Good solvent
Paris-Sud XI, Université de
1185 Viscosity and longest relaxation time of semi-dilute polymer solutions. I. Good solvent M expliqués par un modčle de reptation classique. Abstract. 2014 The zero shear viscosity and longest concentration (4 c/c* 70), we find that : 2014 both the relative viscosity ~r and the longest relaxation time TR
Paris-Sud XI, Université de
On viscosity solutions of certain Hamilton-Jacobi equations: Regularity results and generalized prove that any viscosity solution of the corresponding Hamilton-Jacobi equation on the manifold M). Moreover, we prove that, under additional assumptions and in low dimension, any viscosity solution
The viscosity of Earth's lower mantle inferred from sinking speed of subducted lithosphere
Cizkova, Hana
The viscosity of Earth's lower mantle inferred from sinking speed of subducted lithosphere Hana 2012 Available online 20 February 2012 Keywords: Lower mantle viscosity Slab sinking velocity a b s t r a c t The viscosity of the mantle is indispensable for predicting Earth's mechanical behavior
Sheffield, University of
VISCOSITY OF AMORPHOUS SILICA WITHIN DOREMUS APPROACH Michael I. Ojovan, William E. Lee, Russell J flow is the two-exponential formula of the viscosity AT exp(B/RT)(1+C exp(D/RT)). Derived formula of viscosity has the Arrhenius-type behaviour in both high and low temperature limits and has a form similar
Viscosity and elastic constants of amorphous Si and Ge Ann Witwow@ and Frans Spaepen
Spaepen, Frans A.
Viscosity and elastic constants of amorphous Si and Ge Ann Witwow@ and Frans Spaepen Division expansion. Viscous flow was measured by stress relaxation and was found to be Newtonian. The viscosity of the viscosity of sputter-deposited samples as a function of stress (to establish the Newtonian charac- ter
Bronfenbrenner, James C. (Allentown, PA); Foster, Edward P. (Allentown, PA); Tewari, Krishna (Allentown, PA)
1985-01-01T23:59:59.000Z
A process is disclosed for stabilizing the viscosity of coal derived materials such as an SRC product by adding up to 5.0% by weight of a light volatile phenolic viscosity repressor. The viscosity will remain stabilized for a period of time of up to 4 months.
Viscosity and solute dependence of F-actin translocation by rabbit skeletal heavy meromyosin
Daniel, Tom
Viscosity and solute dependence of F-actin translocation by rabbit skeletal heavy meromyosin P, Ying Chen, Kristi L. Kulin, and Thomas L. Daniel. Viscosity and solute dependence of F the hypothesis that solvent viscosity affects transloca- tion of rhodamine phalloidin-labeled F-actin by rabbit
A low viscosity wedge in subduction zones Magali I. Billen *, Michael Gurnis
Billen, Magali I.
A low viscosity wedge in subduction zones Magali I. Billen *, Michael Gurnis Seismological mantle wedge), which could decrease the viscosity of the mantle locally by several orders of magnitude. Using numerical models we demonstrate that a low viscosity wedge has a dramatic influence on the force
A Viscosity Approach to Total Variation Flows of Non-Divergence Type
Ishii, Hitoshi
A Viscosity Approach to Total Variation Flows of Non-Divergence Type Norbert Poz´ar Graduate School, we will introduce a notion of viscosity solutions for a class of singular nonlinear parabolic viscosity theory does not apply is the unboundedness of the operator on the right-hand side of (5) at u = 0
Viscosity of magmas containing highly deformable bubbles M. Mangaa,*, M. Loewenbergb
Manga, Michael
Viscosity of magmas containing highly deformable bubbles M. Mangaa,*, M. Loewenbergb a Department The shear viscosity of a suspension of deformable bubbles dispersed within a Newtonian Żuid is calculated. For small Ca, bubbles remain nearly spherical, and for suf®ciently large strains the viscosity of suspension
An Adaptive Artificial Viscosity Method for the Saint-Venant System
Kurganov, Alexander
An Adaptive Artificial Viscosity Method for the Saint-Venant System Yunlong Chen, Alexander in applying the adaptive artificial viscosity method proposed in [13] to the Saint-Venant system of shallow enforc- ing the nonlinear stability by adding an artificial viscosity to the PDE system in the regions
Molecular rotors: synthesis and evaluation as viscosity sensors Jeyanthy Sutharsan a
Theodorakis, Emmanuel
Molecular rotors: synthesis and evaluation as viscosity sensors Jeyanthy Sutharsan a , Darcy-mechanical viscosity sensors. These compounds, referred to as molecular rotors, belong to a class of fluorescent probes present the synthesis and spectroscopic characterization of these compounds as viscosity sensors
N. N. Guan; Z. J. He; J. L. Long; X. Z. Cai; Y. G. Ma; J. W. Li; W. Q. Shen
2009-09-02T23:59:59.000Z
By considering the effect of shear viscosity we have investigated the evolution of a chemically equilibrating quark-gluon plasma at finite baryon density. Based on the evolution of the system we have performed a complete calculation for the dilepton production from the following processes: $q\\bar{q}{\\to}l\\bar{l}$, $q\\bar{q}{\\to}gl\\bar{l}$, Compton-like scattering ($qg{\\to}ql\\bar{l}$, $\\bar{q}g{\\to}{\\bar{q}}l\\bar{l}$), gluon fusion $g\\bar{g}{\\to}c\\bar{c}$, annihilation $q\\bar{q}{\\to}c\\bar{c}$ as well as the multiple scattering of quarks. We have found that quark-antiquark annihilation, Compton-like scatterring, gluon fusion, and multiple scattering of quarks give important contributions. Moreover, we have also found that the dilepton yield is an increasing function of the initial quark chemical potential, and the increase of the quark phase lifetime because of the viscosity also obviously raises the dilepton yield.
Apparatus and method for high temperature viscosity and temperature measurements
Balasubramaniam, Krishnan (Mississippi State, MS); Shah, Vimal (Houston, TX); Costley, R. Daniel (Mississippi State, MS); Singh, Jagdish P. (Mississippi State, MS)
2001-01-01T23:59:59.000Z
A probe for measuring the viscosity and/or temperature of high temperature liquids, such as molten metals, glass and similar materials comprises a rod which is an acoustical waveguide through which a transducer emits an ultrasonic signal through one end of the probe, and which is reflected from (a) a notch or slit or an interface between two materials of the probe and (b) from the other end of the probe which is in contact with the hot liquid or hot melt, and is detected by the same transducer at the signal emission end. To avoid the harmful effects of introducing a thermally conductive heat sink into the melt, the probe is made of relatively thermally insulative (non-heat-conductive) refractory material. The time between signal emission and reflection, and the amplitude of reflections, are compared against calibration curves to obtain temperature and viscosity values.
Accretion disc viscosity: a limit on the anisotropy
Nixon, Chris
2015-01-01T23:59:59.000Z
Observations of warped discs can give insight into the nature of angular momentum transport in accretion discs. Only a few objects are known to show strong periodicity on long timescales, but when such periodicity is present it is often attributed to precession of the accretion disc. The X-ray binary Hercules X-1/HZ Herculis (Her X-1) is one of the best examples of such periodicity and has been linked to disc precession since it was first observed. By using the current best-fitting models to Her X-1, which invoke precession driven by radiation warping, I place a constraint on the effective viscosities that act in a warped disc. These effective viscosities almost certainly arise due to turbulence induced by the magneto-rotational instability. The constraints derived here are in agreement with analytical and numerical investigations into the nature of magneto-hydrodynamic disc turbulence, but at odds with some recent global simulations.
Magnetic component of gluon plasma and its viscosity
M. N. Chernodub; H. Verschelde; V. I. Zakharov
2009-05-15T23:59:59.000Z
We discuss the role of the magnetic degrees of freedom of the gluon plasma in its viscosity. The main assumption is that motions of the magnetic component and of the rest of the plasma can be considered as independent. The magnetic component in the deconfined phase is described by a three-dimensional (Euclidean) field theory. The parameters of the theory can be estimated phenomenologically, from the lattice data. It is not ruled out that the magnetic component is superfluid.
Shear viscosity and chemical equilibration of the QGP
Salvatore Plumari; Armando Puglisi; Maria Colonna; Francesco Scardina; Vincenzo Greco
2012-09-04T23:59:59.000Z
We have investigated, in the frame work of the transport approach, different aspects of the QGP created in Heavy Ion Collisions at RHIC and LHC energies. The shear viscosity $\\eta$ has been calculated by using the Green-Kubo relation at the cascade level. We have compared the numerical results for $\\eta$ obtained from the Green-Kubo correlator with the analytical formula in both the Relaxation Time Approximation (RTA) and the Chapman-Enskog approximation (CE). From this comparison we show that in the range of temperature explored in a Heavy Ion collision the RTA underestimates the viscosity by about a factor of 2, while a good agreement is found between the CE approximation and Gree-Kubo relation already at first order of approximation. The agreement with the CE approximation supplies an analytical formula that allows to develop kinetic transport theory at fixed shear viscosity to entropy density ratio, $\\eta/s$. We show some results for the build up of anisotropic flows $v_{2}$ in a transport approach at fixed shear viscosity to entropy density ratio, $\\eta/s$. We study the impact of a T-dependent $\\eta/s(T)$ on the generation of the elliptic flows at both RHIC and LHC. We show that the transport approach provides, in a unified way, a tool able to naturally describe the $v_{2}(p_{T})$ in a wide range of $p_{T}$, including also the description of the rise and fall and saturation of the $v_{2}(p_{T})$ observed at LHC. Finally, we have studied the evolution of the quark-gluon composition employing a Boltzmann-Vlasov transport approach that include: the mean fields dynamics, associated to the quasi-particle model, and the elastic and inelastic collisions for massive quarks and gluons. Following the chemical evolution from an initial gluon dominated plasma we predict a quark dominance close to $T_{C}$ paving the way to an hadronization via quark coalescence.
An alternative approach to viscosity in an accretion disc
R. G. Edgar
2006-10-02T23:59:59.000Z
Purely hydrodynamic numerical experiments into the evolution of astrophysical discs typically include some sort of viscosity in order to cause accretion. In this paper, we demonstrate an alternative method of implementing viscous forces, with extremely good angular momentum conservation properties. The method is based on altering the cell fluxes, rather than incorporating a viscous force. We test this method on the classical `ring spreading' problem, and demonstrate angular momentum conservation at the $10^{-8}$ level.
Extensional viscosity measurements of polyethylene using a melt flow indexer
Moffatt, Scott Gordon
1999-01-01T23:59:59.000Z
. . . . . . . . 142 APPENDIX C: CONSTANT STRESS RHEOMETER TESTING PROCEDURE. . . . . . APPENDIX D: MELT FLOW INDEXER DATA . . . . . 147 APPENDIX E: CAPILLARY RHEOMETER DATA. . . . . . 184 APPENDIX F: OSCILLATORY RHEOMETER DATA . . . . . . . . 213 APPENDIX G...) [Padmanabhan and Macosko (1997)] . . . . . 14 5 Bagley Correction Factor for the Capillary Rheometer. 23 6 Flow Index Determination. . . . . . . 28 7 Definitions of Lengths Used in the Darby Method. 8 Carreau-Yasuda Fit of Complex Viscosity Data for Resin E...
Viscosity and Diffusion: Crowding and Salt Effects in Protein Solutions
Marco Heinen; Fabio Zanini; Felix Roosen-Runge; Diana Fedunová; Fajun Zhang; Marcus Hennig; Tilo Seydel; Ralf Schweins; Michael Sztucki; Marián Antalík; Frank Schreiber; Gerhard Nägele
2011-09-14T23:59:59.000Z
We report on a joint experimental-theoretical study of collective diffusion in, and static shear viscosity of solutions of bovine serum albumin (BSA) proteins, focusing on the dependence on protein and salt concentration. Data obtained from dynamic light scattering and rheometric measurements are compared to theoretical calculations based on an analytically treatable spheroid model of BSA with isotropic screened Coulomb plus hard-sphere interactions. The only input to the dynamics calculations is the static structure factor obtained from a consistent theoretical fit to a concentration series of small-angle X-ray scattering (SAXS) data. This fit is based on an integral equation scheme that combines high accuracy with low computational cost. All experimentally probed dynamic and static properties are reproduced theoretically with an at least semi-quantitative accuracy. For lower protein concentration and low salinity, both theory and experiment show a maximum in the reduced viscosity, caused by the electrostatic repulsion of proteins. The validity range of a generalized Stokes-Einstein (GSE) relation connecting viscosity, collective diffusion coefficient, and osmotic compressibility, proposed by Kholodenko and Douglas [PRE 51, 1081 (1995)] is examined. Significant violation of the GSE relation is found, both in experimental data and in theoretical models, in semi-dilute systems at physiological salinity, and under low-salt conditions for arbitrary protein concentrations.
Waving transport and propulsion in a generalized Newtonian fluid J. Rodrigo Vlez-Cordero
Lauga, Eric
Waving transport and propulsion in a generalized Newtonian fluid J. Rodrigo Vélez-Cordero , Eric in a wavelike fashion to transport fluids and propel cells. Motivated by the ubiquity of non- Newtonian fluids efficiency in a shear-thinning fluid, and in most cases the transport speed in the fluid is also increased
Shear-Viscosity to Entropy Density Ratio of a Relativistic Hadron Gas
Nasser Demir; Steffen A. Bass
2009-03-03T23:59:59.000Z
Ultrarelativistic heavy-ion collisions at the Relativistic Heavy-Ion Collider (RHIC) are thought to have produced a state of matter called the Quark-Gluon-Plasma, characterized by a very small shear viscosity to entropy density ratio $\\eta/s$, near the lower bound predicted for that quantity by Anti-deSitter space/Conformal Field Theory (AdS/CFT) methods. As the produced matter expands and cools, it evolves through a phase described by a hadron gas with rapidly increasing $\\eta/s$. We calculate $\\eta/s$ as a function of temperature in this phase and find that its value poses a challenge for viscous relativistic hydrodynamics, which requires small values of $\\eta/s$ throughout the entire evolution of the reaction in order to successfully describe the collective flow observables at RHIC. We show that the inclusion of non-unit fugacities will reduce $\\eta/s$ in the hadronic phase, yet not sufficiently to be compatible with viscous hydrodynamics. We therefore conclude that the origin of the low viscosity matter at RHIC must be in the partonic phase of the reaction.
DeRoos, B.G.; Downing, J.P. Jr.; Neal, M.P.
1995-11-14T23:59:59.000Z
An improved fluid container for the transport, collection, and dispensing of a sample fluid that maintains the fluid integrity relative to the conditions of the location at which it is taken. More specifically, the invention is a fluid sample transport container that utilizes a fitting for both penetrating and sealing a storage container under controlled conditions. Additionally, the invention allows for the periodic withdrawal of portions of the sample fluid without contamination or intermixing from the environment surrounding the sample container. 13 figs.
Saskatchewan, University of
Standard D-446. Viscosity Bath: The viscosity bath should be filled 5 cm (2") from the top of the bath tank - ASTM D446 - ASTM D2170 - IP 71 - IP 319 - ISO 3140 - DIN 51550 - FTM 791-305 Over Temperature
Murray's law revisited with Qu\\'emada's fluids and fractal trees
Benjamin, Mauroy
2015-01-01T23:59:59.000Z
In 1926, Murray proposed the first law for the optimal design of blood vessels. He minimized the power dissipation arising from the trade-off between fluid circulation and blood maintenance. The law, based on a constant fluid viscosity, states that in the optimal configuration the fluid flow rate inside the vessel is proportional to the cube of the vessel radius, implying that wall shear stress is not dependent on the vessel radius. Murray's law has been found to be true in blood macrocirculation, but not in microcirculation. In 2005, Alarc\\'on et al took into account the non monotonous dependence of viscosity on vessel radius - F{\\aa}hr{\\ae}us - Lindqvist effect - due to phase separation effect of blood. They were able to predict correctly the behavior of wall shear stresses in microcirculation. One last crucial step remains however: to account for the dependence of blood viscosity on shear rates. In this work, we investigate how viscosity dependence on shear rate affects Murray's law. We extended Murray's o...
Drill-in fluids control formation damage
Halliday, W.S. (Baker Hughes Inteq, Houston, TX (United States))
1994-12-01T23:59:59.000Z
Several factors led to development, oil company interest in, and use of payzone drilling fluids, including operator concern about maximizing well production, increasing acceptance of horizontal drilling and openhole completion popularity. This article discusses water-base drill-in'' fluid systems and applications. Payzone damage, including fine solids migration, clay swelling and solids invasion, reduces effective formation permeability, which results in lower production rates. Formation damage is often caused by invasion of normal drilling fluids that contain barite or bentonite. Drill-in systems are designed with special bridging agents to minimize invasion. Several bridging materials designed to form effective filter cake for instantaneous leak-off control can be used. Bridging materials are also designed to minimize stages and time required to clean up wells before production. Fluids with easy-to-remove bridging agents reduce completion costs. Drill-in fluid bridging particles can often be removed more thoroughly than those in standard fluids.
Bag breakup of low viscosity drops in the presence of a continuous air jet
Kulkarni, V., E-mail: vkulkarn@purdue.edu; Sojka, P. E. [Maurice J. Zucrow Laboratories, Purdue University, West Lafayette, Indiana 47906 (United States)
2014-07-15T23:59:59.000Z
This work examines the breakup of a single drop of various low viscosity fluids as it deforms in the presence of continuous horizontal air jet. Such a fragmentation typically occurs after the bulk liquid has disintegrated upon exiting the atomizer and is in the form of an ensemble of drops which undergo further breakup. The drop deformation and its eventual disintegration is important in evaluating the efficacy of a particular industrial process, be it combustion in automobile engines or pesticide spraying in agricultural applications. The interplay between competing influences of surface tension and aerodynamic disruptive forces is represented by the Weber number, We, and Ohnesorge number, Oh, and used to describe the breakup morphology. The breakup pattern considered in our study corresponds to that of a bag attached to a toroidal ring which occurs from ?12 < We < ?16. We aim to address several issues connected with this breakup process and their dependence on We and Oh which have been hitherto unexplored. The We boundary at which breakup begins is theoretically determined and the expression obtained, We=12(1+2/3Oh{sup 2}), is found to match well with experimental data ([L.-P. Hsiang and G. M. Faeth, Int. J. Multiphase Flow 21(4), 545–560 (1995)] and [R. S. Brodkey, “Formation of drops and bubbles,” in The Phenomena of Fluid Motions (Addison-Wesley, Reading, 1967)]). An exponential growth in the radial extent of the deformed drop and the streamline dimension of the bag is predicted by a theoretical model and confirmed by experimental findings. These quantities are observed to strongly depend on We. However, their dependence on Oh is weak.
Bulk viscosity in a plasma of confining gluons
Wojciech Florkowski; Radoslaw Ryblewski; Nan Su; Konrad Tywoniuk
2015-04-13T23:59:59.000Z
We investigate dynamic properties of a plasma whose constituents are confining gluons resulting from the Gribov quantization. In a static formulation, this system reproduces qualitatively the pure-glue equation of state and thereby encodes crucial features of the phase transition. The dynamic description proposed in this work allows us to study non-equilibrium transport phenomena with the inclusion of confinement effects. In particular, we determine the non-equilibrium behaviour of the interaction measure (trace anomaly) and find the form of the bulk viscosity coefficient. The latter may be used in phenomenological applications to heavy-ion collisions.
Measurement of surface tension and viscosity by open capillary techniques
Rye,Robert R. (Albuquerque, NM), Yost,Frederick G. (Cedar Crest, NM)
1998-01-01T23:59:59.000Z
An open-channel capillary is provided, having preferably a v-shaped groove in a flat wettable surface. The groove has timing marks and a source marker in which the specimen to be tested is deposited. The time of passage between the timing marks is recorded, and the ratio of surface tension .gamma. to viscosity .mu. is determined from the equation given below: ##EQU1## where h.sub.0 is the groove depth, .alpha. is the groove angle, .theta. is the liquid/solid contact angle, and t is the flow time. It has been shown by the
Bulk viscosity in a plasma of confining gluons
Florkowski, Wojciech; Su, Nan; Tywoniuk, Konrad
2015-01-01T23:59:59.000Z
We investigate dynamic properties of a plasma whose constituents are confining gluons resulting from the Gribov quantization. In a static formulation, this system reproduces qualitatively the pure-glue equation of state and thereby encodes crucial features of the phase transition. The dynamic description proposed in this work allows us to study non-equilibrium transport phenomena with the inclusion of confinement effects. In particular, we determine the non-equilibrium behaviour of the interaction measure (trace anomaly) and find the form of the bulk viscosity coefficient. The latter may be used in phenomenological applications to heavy-ion collisions.
Standardization of Thermo-Fluid Modeling in Modelica.Fluid
Franke, Rudiger
2010-01-01T23:59:59.000Z
Thermo-Fluid Systems, Modelica 2003 Conference, Linköping,H. Tummescheit: The Modelica Fluid and Media Library forThermo-Fluid Pipe Networks, Modelica 2006 Conference, Vi-
Fluid Bed Combustion Applied to Industrial Waste
Mullen, J. F.; Sneyd, R. J.
Because of its unique ability to handle a wide variety of liquids and solids in an energy efficient and environmentally acceptable manner, fluid bed combustion is being increasingly applied to the utilization of waste materials and low grade fuels...
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 ...
Friction-Induced Fluid Heating in Nanoscale Helium Flows
Li Zhigang [Department of Mechanical Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon (Hong Kong)
2010-05-21T23:59:59.000Z
We investigate the mechanism of friction-induced fluid heating in nanoconfinements. Molecular dynamics simulations are used to study the temperature variations of liquid helium in nanoscale Poiseuille flows. It is found that the fluid heating is dominated by different sources of friction as the external driving force is changed. For small external force, the fluid heating is mainly caused by the internal viscous friction in the fluid. When the external force is large and causes fluid slip at the surfaces of channel walls, the friction at the fluid-solid interface dominates over the internal friction in the fluid and is the major contribution to fluid heating. An asymmetric temperature gradient in the fluid is developed in the case of nonidentical walls and the general temperature gradient may change sign as the dominant heating factor changes from internal to interfacial friction with increasing external force.
One Time-step Finite Element Discretization of the Equation of Motion of Two-fluid Flows
Maury, Bertrand
obtained at each time step when dis- cretizing the lubricated transportation of heavy crude oil in a horizontal pipeline. In the petroleum industry, an efficient way for transporting heavy crude oil to the pipe wall and it surrounds the fluid with high viscosity (heavy oil). It is assumed that the flow
Shear Viscosity to Entropy Density Ratio in Six Derivative Gravity
Nabamita Banerjee; Suvankar Dutta
2009-04-01T23:59:59.000Z
We calculate shear viscosity to entropy density ratio in presence of four derivative (with coefficient $\\alpha'$) and six derivative (with coefficient $\\alpha'^2$) terms in bulk action. In general, there can be three possible four derivative terms and ten possible six derivative terms in the Lagrangian. Among them two four derivative and eight six derivative terms are ambiguous, i.e., these terms can be removed from the action by suitable field redefinitions. Rest are unambiguous. According to the AdS/CFT correspondence all the unambiguous coefficients (coefficients of unambiguous terms) can be fixed in terms of field theory parameters. Therefore, any measurable quantities of boundary theory, for example shear viscosity to entropy density ratio, when calculated holographically can be expressed in terms of unambiguous coefficients in the bulk theory (or equivalently in terms of boundary parameters). We calculate $\\eta/s$ for generic six derivative gravity and find that apparently it depends on few ambiguous coefficients at order $\\alpha'^2$. We calculate six derivative corrections to central charges $a$ and $c$ and express $\\eta/s$ in terms of these central charges and unambiguous coefficients in the bulk theory.
Lenert, Andrej
2012-01-01T23:59:59.000Z
The choice of heat transfer fluids has significant effects on the performance, cost, and reliability of solar thermal systems. In this chapter, we evaluate existing heat transfer fluids such as oils and molten salts based ...
Barran, Brian Arthur
2006-08-16T23:59:59.000Z
This thesis presents a method for simulating fluids on a view dependent grid structure to exploit level-of-detail with distance to the viewer. Current computer graphics techniques, such as the Stable Fluid and Particle Level Set methods...
Forrest, G.T.
1992-04-07T23:59:59.000Z
This patent describes a product for use in the drilling of wells. It comprises a drilling fluid and peanut hulls ground to powder form added to the drilling fluid.
Standardization of Thermo-Fluid Modeling in Modelica.Fluid
Franke, Rudiger
2010-01-01T23:59:59.000Z
Ob- ject-Oriented Modeling of Thermo-Fluid Systems, Modelicable and Compressible Thermo-Fluid Pipe Networks, ModelicaStandardization of Thermo-Fluid Modeling in Modelica.Fluid
Inertial Coupling Method for particles in an incompressible fluctuating fluid
F. Balboa Usabiaga; R. Delgado-Buscalioni; B. E. Griffith; A. Donev
2015-07-28T23:59:59.000Z
We develop an inertial coupling method for modeling the dynamics of point-like 'blob' particles immersed in an incompressible fluid, generalizing previous work for compressible fluids. The coupling consistently includes excess (positive or negative) inertia of the particles relative to the displaced fluid, and accounts for thermal fluctuations in the fluid momentum equation. The coupling between the fluid and the blob is based on a no-slip constraint equating the particle velocity with the local average of the fluid velocity, and conserves momentum and energy. We demonstrate that the formulation obeys a fluctuation-dissipation balance, owing to the non-dissipative nature of the no-slip coupling. We develop a spatio-temporal discretization that preserves, as best as possible, these properties of the continuum formulation. In the spatial discretization, the local averaging and spreading operations are accomplished using compact kernels commonly used in immersed boundary methods. We find that the special properties of these kernels make the discrete blob a particle with surprisingly physically-consistent volume, mass, and hydrodynamic properties. We develop a second-order semi-implicit temporal integrator that maintains discrete fluctuation-dissipation balance, and is not limited in stability by viscosity. Furthermore, the temporal scheme requires only constant-coefficient Poisson and Helmholtz linear solvers, enabling a very efficient and simple FFT-based implementation on GPUs. We numerically investigate the performance of the method on several standard test problems...
Effects of pore fluids in the subsurface on ultrasonic wave propagation
Seifert, P.K.
1998-05-01T23:59:59.000Z
This thesis investigates ultrasonic wave propagation in unconsolidated sands in the presence of different pore fluids. Laboratory experiments have been conducted in the sub-MHz range using quartz sand fully saturated with one or two liquids. Elastic wave propagation in unconsolidated granular material is computed with different numerical models: in one-dimension a scattering model based on an analytical propagator solution, in two dimensions a numerical approach using the boundary integral equation method, in three dimensions the local flow model (LFM), the combined Biot and squirt flow theory (BISQ) and the dynamic composite elastic medium theory (DYCEM). The combination of theoretical and experimental analysis yields a better understanding of how wave propagation in unconsolidated sand is affected by (a) homogeneous phase distribution; (b) inhomogeneous phase distribution, (fingering, gas inclusions); (c) pore fluids of different viscosity; (d) wettabilities of a porous medium. The first study reveals that the main ultrasonic P-wave signatures, as a function of the fraction on nonaqueous-phase liquids in initially water-saturated sand samples, can be explained by a 1-D scattering model. The next study investigates effects of pore fluid viscosity on elastic wave propagation, in laboratory experiments conducted with sand samples saturated with fluids of different viscosities. The last study concentrates on the wettability of the grains and its effect on elastic wave propagation and electrical resistivity.
Bulk viscosity of strange matter and r-modes in neutron stars
Debarati Chatterjee; Debades Bandyopadhyay
2008-12-30T23:59:59.000Z
We discuss bulk viscosity due to non-leptonic processes involving hyperons and Bose-Einstein condensate of negatively charged kaons in neutron stars. It is noted that the hyperon bulk viscosity coefficient is a few order of magnitude larger than that of the case with the condensate. Further it is found that the hyperon bulk viscosity is suppressed in a superconducting phase. The hyperon bulk viscosity efficiently damps the r-mode instability in neutron stars irrespective of whether a superconducting phase is present or not in neutron star interior.
A Strongly Coupled Anisotropic Fluid From Dilaton Driven Holography
Sachin Jain; Nilay Kundu; Kallol Sen; Aninda Sinha; Sandip P. Trivedi
2015-01-13T23:59:59.000Z
We consider a system consisting of $5$ dimensional gravity with a negative cosmological constant coupled to a massless scalar, the dilaton. We construct a black brane solution which arises when the dilaton satisfies linearly varying boundary conditions in the asymptotically $AdS_5$ region. The geometry of this black brane breaks rotational symmetry while preserving translational invariance and corresponds to an anisotropic phase of the system. Close to extremality, where the anisotropy is big compared to the temperature, some components of the viscosity tensor become parametrically small compared to the entropy density. We study the quasi normal modes in considerable detail and find no instability close to extremality. We also obtain the equations for fluid mechanics for an anisotropic driven system in general, working upto first order in the derivative expansion for the stress tensor, and identify additional transport coefficients which appear in the constitutive relation. For the fluid of interest we find that the parametrically small viscosity can result in a very small force of friction, when the fluid is enclosed between appropriately oriented parallel plates moving with a relative velocity.
Iu. A. Karpenko; P. Huovinen; H. Petersen; M. Bleicher
2015-02-06T23:59:59.000Z
Hybrid approaches based on relativistic hydrodynamics and transport theory have been successfully applied for many years for the dynamical description of heavy ion collisions at ultrarelativistic energies. In this work a new viscous hybrid model employing the hadron transport approach UrQMD for the early and late non-equilibrium stages of the reaction, and 3+1 dimensional viscous hydrodynamics for the hot and dense quark-gluon plasma stage is introduced. This approach includes the equation of motion for finite baryon number, and employs an equation of state with finite net-baryon density to allow for calculations in a large range of beam energies. The parameter space of the model is explored, and constrained by comparison with the experimental data for bulk observables from SPS and the phase I beam energy scan at RHIC. The favored parameter values depend on energy, but allow to extract the effective value of the shear viscosity coefficient over entropy density ratio $\\eta/s$ in the fluid phase for the whole energy region under investigation. The estimated value of $\\eta/s$ increases with decreasing collision energy, which may indicate that $\\eta/s$ of the quark-gluon plasma depends on baryochemical potential $\\mu_B$.
QCD Viscosity to Entropy Density Ratio in the Hadronic Phase
Jiunn-Wei Chen; Yen-Han Li; Yen-Fu Liu; Eiji Nakano
2007-04-20T23:59:59.000Z
Shear viscosity (eta) of QCD in the hadronic phase is computed by the coupled Boltzmann equations of pions and nucleons in low temperatures and low baryon number densities. The eta to entropy density ratio eta/s maps out the nuclear gas-liquid phase transition by forming a valley tracing the phase transition line in the temperature-chemical potential plane. When the phase transition turns into a crossover, the eta/s valley gradually disappears. We suspect the general feature for a first-order phase transition is that eta/s has a discontinuity in the bottom of the eta/s valley. The discontinuity coincides with the phase transition line and ends at the critical point. Beyond the critical point, a smooth eta/s valley is seen. However, the valley could disappear further away from the critical point. The eta/s measurements might provide an alternative to identify the critical points.
Hall viscosity to entropy ratio in higher derivative theories
Dibakar Roychowdhury
2014-09-18T23:59:59.000Z
In this paper based on the basic principles of gauge/gravity duality we compute the hall viscosity to entropy ratio in the presence of various higher derivative corrections to the dual gravitational description embedded in an asymptotically $ AdS_{4} $ space time. As the first step of our analysis, considering the back reaction we impose higher derivative corrections to the abelian gauge sector of the theory where we notice that the ratio indeed gets corrected at the leading order in the coupling. Considering the probe limit as a special case we compute this leading order correction over the fixed background of the charged black brane solution. Finally we consider higher derivative ($ R^{2} $) correction to the gravity sector of the theory where we notice that the above ratio might get corrected at the sixth derivative level.
Cavitation from bulk viscosity in neutron stars and quark stars
Jes Madsen
2009-09-30T23:59:59.000Z
The bulk viscosity in quark matter is sufficiently high to reduce the effective pressure below the corresponding vapor pressure during density perturbations in neutron stars and strange stars. This leads to mechanical instability where the quark matter breaks apart into fragments comparable to cavitation scenarios discussed for ultra-relativistic heavy-ion collisions. Similar phenomena may take place in kaon-condensed stellar cores. Possible applications to compact star phenomenology include a new mechanism for damping oscillations and instabilities, triggering of phase transitions, changes in gravitational wave signatures of binary star inspiral, and astrophysical formation of strangelets. At a more fundamental level it points to the possible inadequacy of a hydrodynamical treatment of these processes in compact stars.
Cavitation from bulk viscosity in neutron stars and strange stars
Madsen, Jes
2009-01-01T23:59:59.000Z
The bulk viscosity in quark matter is sufficiently high to reduce the effective pressure below the corresponding vapor pressure during density perturbations in neutron stars and strange stars. This leads to mechanical instability where the quark matter breaks apart into fragments comparable to cavitation scenarios discussed for ultra-relativistic heavy-ion collisions. Similar phenomena may take place in kaon-condensed stellar cores. Possible applications to compact star phenomenology include a new mechanism for damping oscillations and instabilities, triggering of phase transitions, changes in gravitational wave signatures of binary star inspiral, and astrophysical formation of strangelets. At a more fundamental level it points to the possible inadequacy of a hydrodynamical treatment of these processes in compact stars.
Low-melting point inorganic nitrate salt heat transfer fluid
Bradshaw, Robert W. (Livermore, CA); Brosseau, Douglas A. (Albuquerque, NM)
2009-09-15T23:59:59.000Z
A low-melting point, heat transfer fluid made of a mixture of four inorganic nitrate salts: 9-18 wt % NaNO.sub.3, 40-52 wt % KNO.sub.3, 13-21 wt % LiNO.sub.3, and 20-27 wt % Ca(NO.sub.3).sub.2. These compositions can have liquidus temperatures less than 100 C; thermal stability limits greater than 500 C; and viscosity in the range of 5-6 cP at 300 C; and 2-3 cP at 400 C.
On preparation of viscous pore fluids for dynamic centrifuge modelling
Adamidis, O.; Madabhushi, S. P. G.
2014-11-21T23:59:59.000Z
dynamic cen- trifuge tests, the use of water as pore fluid can limit the generation of excess pore pressures in sand formations below gravel embankments, lowering the recorded crest settlement signif- icantly. Chian and Madabhushi [2010] exam- ined... with changing 4 1.2 1.6 2 2.4 2.8 3.2 0 40 80 120 160 200 Concentration [%] V is co si ty [m P a · s] measurements at 20?C best fit (8th order) best fit (power law) Stewart et al. [1998] Figure 2: Viscosity change with concentration 1.2 1.6 2 2.4 2.8 3.2 1...
Miller, Jan D; Hupka, Jan; Aranowski, Robert
2012-11-20T23:59:59.000Z
A spinning fluids reactor, includes a reactor body (24) having a circular cross-section and a fluid contactor screen (26) within the reactor body (24). The fluid contactor screen (26) having a plurality of apertures and a circular cross-section concentric with the reactor body (24) for a length thus forming an inner volume (28) bound by the fluid contactor screen (26) and an outer volume (30) bound by the reactor body (24) and the fluid contactor screen (26). A primary inlet (20) can be operatively connected to the reactor body (24) and can be configured to produce flow-through first spinning flow of a first fluid within the inner volume (28). A secondary inlet (22) can similarly be operatively connected to the reactor body (24) and can be configured to produce a second flow of a second fluid within the outer volume (30) which is optionally spinning.
Fluid Dynamics Seminar Fluid Dynamics Research Centre
Davies, Christopher
France) 8th Nov. Future Trends in Condition Monitoring of Rotating Machines Using System Identification Simulation of the Cooling of a Simplified Brake Disc Dr. Thorsten J. Möller, (Institute for Fluid Mechanics
Fluid Dynamics Seminar Fluid Dynamics Research Centre
Thomas, Peter J.
France) 8 th Nov. Future Trends in Condition Monitoring of Rotating Machines Using System Identification Simulation of the Cooling of a Simplified Brake Disc Dr. Thorsten J. Möller, (Institute for Fluid Mechanics
Method of preparing a high solids content, low viscosity ceramic slurry
Tiegs, Terry N. (Lenoir City, TN); Wittmer, Dale E. (Carbondale, IL)
1995-01-01T23:59:59.000Z
A method for producing a high solids content, low viscosity ceramic slurry composition comprises turbomilling a dispersion of a ceramic powder in a liquid to form a slurry having a viscosity less than 100 centipoise and a solids content equal to or greater than 48 volume percent.
Method of preparing a high solids content, low viscosity ceramic slurry
Tiegs, T.N.; Wittmer, D.E.
1995-10-10T23:59:59.000Z
A method for producing a high solids content, low viscosity ceramic slurry composition comprises turbomilling a dispersion of a ceramic powder in a liquid to form a slurry having a viscosity less than 100 centipoise and a solids content equal to or greater than 48 volume percent.
Shear viscosity from R-charged AdS black holes
J. Mas
2006-03-07T23:59:59.000Z
We compute the shear viscosity in the supersymmetric Yang-Mills theory dual to the STU background. This is a thermal gauge theory with a chemical potential. The quotient of the shear viscosity over the entropy density exhibits no deviation from the well known result 1/4\\pi.
Enhanced thermal conductivity and viscosity of copper nanoparticles in ethylene glycol nanofluid
Enhanced thermal conductivity and viscosity of copper nanoparticles in ethylene glycol nanofluid J conductivity and viscosity of copper nanoparticles in ethylene glycol. The nanofluid was prepared calculations suggest that this nanofluid would not be beneficial as a coolant in heat exchangers without
Experimental investigation of nanofluid shear and longitudinal viscosities Aaron J. Schmidt,1,a
Experimental investigation of nanofluid shear and longitudinal viscosities Aaron J. Schmidt,1,a. The measurements indicate that for the decane-based nanofluids the nanoparticles do not form clusters. In the case of PAO nanofluids, the measurements of longitudinal viscosity and the corresponding values
Role of viscosity in the accurate prediction of source-terms for high molecular weight substances
Shaikh, Irfan Yusuf
1999-01-01T23:59:59.000Z
and pressure, and mixing effects. The viscosity prediction uses an improvement on current predictions by combining b-parameter and Modified Chung-Lee-starling (MCLS) viscosity predictions for the employed pseudo-mixtures. The source-term model used is SPILLS...
Firoozabadi, Abbas
Natural Gas Hydrate Particles in Oil-Free Systems with Kinetic Inhibition and Slurry Viscosity, reduction of slurry viscosity, and corrosion inhibition. INTRODUCTION Water often forms gas hydrates antiagglomeration (AA) in the natural gas hydrate literature. The main limitation to application has been the need
Bending Creep Test to Measure the Viscosity of Porous Materials during Sintering
Messing, Gary L.
Bending Creep Test to Measure the Viscosity of Porous Materials during Sintering Sang-Ho Lee creep test is proposed for measuring the change in viscosity of a porous material during densification be measured. Experiments with porous Y2O3-stabilized ZrO2 beams were used to illustrate the bending creep test
Viscosity and reptation time in polystyrene-benzene semidilute solutions M. Adam and M. Delsanti
Paris-Sud XI, Université de
L-523 Viscosity and reptation time in polystyrene-benzene semidilute solutions M. Adam and M viscosity ~ and reptation time TR in semidilute polystyrene-benzene solutions. We have obtained, our aim is to study the viscoelastic properties of polystyrene-benzene systems in a well defined
Creating fluid injectivity in tar sands formations
Stegemeier, George Leo; Beer, Gary Lee; Zhang, Etuan
2012-06-05T23:59:59.000Z
Methods for treating a tar sands formation are described herein. Methods for treating a tar sands may include heating a portion of a hydrocarbon layer in the formation from one or more heaters located in the portion. The heat may be controlled to increase the permeability of at least part of the portion to create an injection zone in the portion with an average permeability sufficient to allow injection of a fluid through the injection zone. A drive fluid and/or an oxidizing fluid may be provided into the injection zone. At least some hydrocarbons including mobilized hydrocarbons are produced from the portion.
Creating fluid injectivity in tar sands formations
Stegemeier, George Leo; Beer, Gary Lee; Zhang, Etuan
2010-06-08T23:59:59.000Z
Methods for treating a tar sands formation are described herein. Methods for treating a tar sands may include heating a portion of a hydrocarbon layer in the formation from one or more heaters located in the portion. The heat may be controlled to increase the permeability of at least part of the portion to create an injection zone in the portion with an average permeability sufficient to allow injection of a fluid through the injection zone. A drive fluid and/or an oxidizing fluid may be provided into the injection zone. At least some hydrocarbons are produced from the portion.
Effect of Resins and DBSA on Asphaltene Precipitation from Petroleum Fluids
Firoozabadi, Abbas
Effect of Resins and DBSA on Asphaltene Precipitation from Petroleum Fluids Lamia Goual and Abbas different petroleum fluids. Various resins are added to three different petroleum fluids to measure of precipitation. However, addition of resins to a petroleum fluid increases the amount of precipitated asphaltenes
Roar Skartlien; Espen Sollum; Andreas Akselsen; Paul Meakin
2012-07-01T23:59:59.000Z
A 3D lattice Boltzmann model for two-phase flow with amphiphilic surfactant was used to investigate the evolution of emulsion morphology and shear stress in starting shear flow. The interfacial contributions were analyzed for low and high volume fractions and varying surfactant activity. A transient viscoelastic contribution to the emulsion rheology under constant strain rate conditions was attributed to the interfacial stress. For droplet volume fractions below 0.3 and an average capillary number of about 0.25, highly elliptical droplets formed. Consistent with affine deformation models, gradual elongation of the droplets increased the shear stress at early times and reduced it at later times. Lower interfacial tension with increased surfactant activity counterbalanced the effect of increased interfacial area, and the net shear stress did not change significantly. For higher volume fractions, co-continuous phases with a complex topology were formed. The surfactant decreased the interfacial shear stress due mainly to advection of surfactant to higher curvature areas. Our results are in qualitative agreement with experimental data for polymer blends in terms of transient interfacial stresses and limited enhancement of the emulsion viscosity at larger volume fractions where the phases are co-continuous.
Goloshubin, Gennady M. (Sugar Land, TX); Korneev, Valeri A. (Lafayette, CA)
2005-09-06T23:59:59.000Z
A method for identifying, imaging and monitoring dry or fluid-saturated underground reservoirs using seismic waves reflected from target porous or fractured layers is set forth. Seismic imaging the porous or fractured layer occurs by low pass filtering of the windowed reflections from the target porous or fractured layers leaving frequencies below low-most corner (or full width at half maximum) of a recorded frequency spectra. Additionally, the ratio of image amplitudes is shown to be approximately proportional to reservoir permeability, viscosity of fluid, and the fluid saturation of the porous or fractured layers.
Goloshubin, Gennady M.; Korneev, Valeri A.
2006-11-14T23:59:59.000Z
A method for identifying, imaging and monitoring dry or fluid-saturated underground reservoirs using seismic waves reflected from target porous or fractured layers is set forth. Seismic imaging the porous or fractured layer occurs by low pass filtering of the windowed reflections from the target porous or fractured layers leaving frequencies below low-most corner (or full width at half maximum) of a recorded frequency spectra. Additionally, the ratio of image amplitudes is shown to be approximately proportional to reservoir permeability, viscosity of fluid, and the fluid saturation of the porous or fractured layers.
Angel, S.M.
1987-02-27T23:59:59.000Z
Particular gases or liquids are detected with a fiber optic element having a cladding or coating of a material which absorbs the fluid or fluids and which exhibits a change of an optical property, such as index of refraction, light transmissiveness or fluoresence emission, for example, in response to absorption of the fluid. The fluid is sensed by directing light into the fiber optic element and detecting changes in the light, such as exit angle changes for example, that result from the changed optical property of the coating material. The fluid detector may be used for such purposes as sensing toxic or explosive gases in the atmosphere, measuring ground water contamination or monitoring fluid flows in industrial processes, among other uses. 10 figs.
Angel, S. Michael (Livermore, CA)
1989-01-01T23:59:59.000Z
Particular gases or liquids are detected with a fiber optic element (11, 11a to 11j) having a cladding or coating of a material (23, 23a to 23j) which absorbs the fluid or fluids and which exhibits a change of an optical property, such as index of refraction, light transmissiveness or fluoresence emission, for example, in response to absorption of the fluid. The fluid is sensed by directing light into the fiber optic element and detecting changes in the light, such as exit angle changes for example, that result from the changed optical property of the coating material. The fluid detector (24, 24a to 24j) may be used for such purposes as sensing toxic or explosive gases in the atmosphere, measuring ground water contamination or monitoring fluid flows in industrial processes, among other uses.
Metalworking and machining fluids
Erdemir, Ali (Naperville, IL); Sykora, Frank (Caledon, ON, CA); Dorbeck, Mark (Brighton, MI)
2010-10-12T23:59:59.000Z
Improved boron-based metal working and machining fluids. Boric acid and boron-based additives that, when mixed with certain carrier fluids, such as water, cellulose and/or cellulose derivatives, polyhydric alcohol, polyalkylene glycol, polyvinyl alcohol, starch, dextrin, in solid and/or solvated forms result in improved metalworking and machining of metallic work pieces. Fluids manufactured with boric acid or boron-based additives effectively reduce friction, prevent galling and severe wear problems on cutting and forming tools.
Bush, John W.M.
of Technology We examine the form of the free surface flows resulting from the collision of equal jets at an oblique angle. Glycerolwater solutions with viscosities of 1550 cS were pumped at flow rates of 1040 cc is determined by the pinch-off of the fishbones Fig. 4 . At the highest flow rates examined, the flow
MECH 386 INDUSTRIAL FLUID MECHANICS INDUSTRIAL FLUID MECHANICS
Phani, A. Srikantha
MECH 386 INDUSTRIAL FLUID MECHANICS 1 INDUSTRIAL FLUID MECHANICS MECH 386 Contact information Dr This course is an introduction to industrial fluid mechanics. According to J. C. R. Hunt (a famous fluid mechanics specialist): "industrial fluid mechanics broadly covers those aspects of the design, manufacture
An Experimental Setup to Study the Settling Behavior of Epoxy Based Fluids
El-Mallawany, Ibrahim Ismail
2012-07-16T23:59:59.000Z
or liquid. It assumes that the settling object is a small sphere and that the difference in densities is not large. This is because Stokes? law takes into account only the viscous forces that cause drag and does not account for drag due to impact forces.... Therefore, Stokes? law only applies where Reynolds number is very low. Stokes? law is given by the following equation (Batchelor 1967) ??????.?. (1) where Fd is the drag force, ? is the fluid?s viscosity, R is the sphere?s radius and V...
Holographic Screens and Transport Coefficients in the Fluid/Gravity Correspondence
Christopher Eling; Yaron Oz
2011-11-04T23:59:59.000Z
We consider in the framework of the fluid/gravity correspondence the dynamics of hypersurfaces located in the holographic radial direction at r = r_0. We prove that these hypersurfaces evolve, to all orders in the derivative expansion and including all higher curvature corrections, according to the same hydrodynamics equations with identical transport coefficients. The analysis is carried out for normal fluids as well as for superfluids. Consequently, this proves the exactness of the bulk viscosity formula derived in arXiv:1103.1657 via the null horizon dynamics.
V European Conference on Computational Fluid Dynamics ECCOMAS CFD 2010
Berning, Torsten
V European Conference on Computational Fluid Dynamics ECCOMAS CFD 2010 J. C. F. Pereira and A, increase the mixing of fuel and oxidant, control formation of harmful emissions, and increase the life
Boyer, Edmond
1 Viscosity of an electro-rheological suspension with internal rotations. E. Lemaire, L.Lobry, N (Quincke rotation) which, in turn, leads to a drastic decrease of the apparent viscosity of the suspension. The purpose of the paper is to provide a relation between the apparent viscosity of the suspension and the E
Paris-Sud XI, Université de
L-529 Viscosity and radial distribution function in PbxSe(1-x) melts for stoechiometric by lead atoms sur- rounded by Se atoms are considered. Kinematic viscosity data are compared a molecular structure in the liquid state rather than a chain-structure [1]. Viscosity is very sensitive
Majda, Marcin
Viscosity of the Aqueous Liquid/Vapor Interfacial Region: 2D Electrochemical Measurements, and that it is coupled to the interfacial water via hydrogen bonding with H2O. In view of this postulate, the viscosity into the dynamic characteristics of aqueous interfaces. Thus, parameters such as the viscosity of water
Theory comparison and numerical benchmarking on neoclassical toroidal viscosity torque
Wang, Zhirui; Park, Jong-Kyu; Logan, Nikolas; Kim, Kimin; Menard, Jonathan E. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)] [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States); Liu, Yueqiang [Euratom/CCFE Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom)] [Euratom/CCFE Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom)
2014-04-15T23:59:59.000Z
Systematic comparison and numerical benchmarking have been successfully carried out among three different approaches of neoclassical toroidal viscosity (NTV) theory and the corresponding codes: IPEC-PENT is developed based on the combined NTV theory but without geometric simplifications [Park et al., Phys. Rev. Lett. 102, 065002 (2009)]; MARS-Q includes smoothly connected NTV formula [Shaing et al., Nucl. Fusion 50, 025022 (2010)] based on Shaing's analytic formulation in various collisionality regimes; MARS-K, originally computing the drift kinetic energy, is upgraded to compute the NTV torque based on the equivalence between drift kinetic energy and NTV torque [J.-K. Park, Phys. Plasma 18, 110702 (2011)]. The derivation and numerical results both indicate that the imaginary part of drift kinetic energy computed by MARS-K is equivalent to the NTV torque in IPEC-PENT. In the benchmark of precession resonance between MARS-Q and MARS-K/IPEC-PENT, the agreement and correlation between the connected NTV formula and the combined NTV theory in different collisionality regimes are shown for the first time. Additionally, both IPEC-PENT and MARS-K indicate the importance of the bounce harmonic resonance which can greatly enhance the NTV torque when E×B drift frequency reaches the bounce resonance condition.
Finite viscous disks with time-independent viscosity
Lipunova, Galina V
2015-01-01T23:59:59.000Z
We find the Green's functions for the accretion disk with the fixed outer radius and time-independent viscosity. With the Green's functions, a viscous evolution of the disk with any initial conditions can be described. Two types of the inner boundary conditions are considered: the zero stress tensor and the zero accretion rate. The variable mass inflow at the outer radius can also be included. The well-known exponential decline of the accretion rate is a part of the solution with the inner zero stress tensor. The solution with the zero central accretion rate is applicable to the disks around stars with the magnetosphere's boundary exceeding the corotation radius. Using the solution, the viscous evolution of disks in some binary systems can be studied. We apply the solution with zero inner stress tensor to outbursts of short-period X-ray transients during the time around the peak. It is found that for the Kramers' regime of opacity and the initial surface density proportional to the radius, the rise time to th...
Hall viscosity from elastic gauge fields in Dirac crystals
Alberto Cortijo; Yago Ferreirós; Karl Landsteiner; María A. H. Vozmediano
2015-06-16T23:59:59.000Z
The combination of Dirac physics and elasticity has been explored at length in graphene where the so--called "elastic gauge fields" have given rise to an entire new field of research and applications: Straintronics. The fact that these elastic fields couple to fermions as the electromagnetic field, implies that many electromagnetic responses will have elastic counterparts not explored before. In this work we will first show that the presence of elastic gauge fields will be the rule rather than the exception in most of the topologically non--trivial materials in two and three dimensions. In particular we will extract the elastic gauge fields associated to the recently observed Weyl semimetals, the "three dimensional graphene". As it is known, quantum electrodynamics suffers from the chiral anomaly whose consequences have been recently explored in matter systems. We will show that, associated to the physics of the anomalies, and as a counterpart of the Hall conductivity, elastic materials will have a Hall viscosity in two and three dimensions with a coefficient orders of magnitude bigger than the previously studied response. The magnitude and generality of the new effect will greatly improve the chances for the experimental observation of this topological, non dissipative response.
Bench-mark solution for a penny-shaped hydraulic fracture driven by a thinning fluid
Linkov, Aleksandr
2015-01-01T23:59:59.000Z
The paper presents a solution for axisymmetric propagation of a penny-shaped crack driven by a thinning fluid. The solution to the accuracy of four significant digits, at least, is obtained on the basis of the modified formulation of hydraulic fracture problem by employing the particle velocity, rather than conventionally used flux. This serves to properly organize iterations in the opening after reducing the problem to the self-similar form. Numerical results obtained show relatively small dependence of self-similar quantities (fracture radius, propagation speed, opening, particle velocity, pressure, flux) on the behavior index of a thinning fluid. The results provide bench marks for the accuracy control of truly 3D simulators and they serve for assigning an apparent viscosity when simulating the action of a thinning fluid by replacing it with an equivalent Newtonian fluid.
Osinski, Charles Anthony
1963-01-01T23:59:59.000Z
the research. Assistance given the author by the staff of the Texas A. & M. Data Processing Center is also appreciated. I also wis'h to express my sincere appreciation to Colonel George E. Rath, USAF, without whose personal interest the opportunity... to the shearing rate, i. e. , or F/A & dv/dy dv dy or T (l) This is Newton's law of viscosity, where the constant of proportlonaltty, ~, is called the Newtonian viscosity. Newtonian viscosity is independent of shear under isothermal-isobaric conditions...
Hoff, Brian D.; Johnson, Kris William; Algrain, Marcelo C.; Akasam, Sivaprasad
2006-06-06T23:59:59.000Z
A method of controlling the delivery of fluid to an engine includes receiving a fuel flow rate signal. An electric pump is arranged to deliver fluid to the engine. The speed of the electric pump is controlled based on the fuel flow rate signal.
Jakaboski, Juan-Carlos (Albuquerque, NM); Hughs, Chance G. (Albuquerque, NM); Todd, Steven N. (Rio Rancho, NM)
2012-01-10T23:59:59.000Z
A fluid blade disablement (FBD) tool that forms both a focused fluid projectile that resembles a blade, which can provide precision penetration of a barrier wall, and a broad fluid projectile that functions substantially like a hammer, which can produce general disruption of structures behind the barrier wall. Embodiments of the FBD tool comprise a container capable of holding fluid, an explosive assembly which is positioned within the container and which comprises an explosive holder and explosive, and a means for detonating. The container has a concavity on the side adjacent to the exposed surface of the explosive. The position of the concavity relative to the explosive and its construction of materials with thicknesses that facilitate inversion and/or rupture of the concavity wall enable the formation of a sharp and coherent blade of fluid advancing ahead of the detonation gases.
Continuum limit of lattice gas fluid dynamics
Teixeira, C.M.
1992-01-01T23:59:59.000Z
The general theory for multiple-speed lattice gas algorithm (LGAs) is developed where previously only a single-speed theory existed. A series of microdynamical multiple-speed models are developed that effectively erase the underlying lattice from the macroscopic dynamics allowing the LGA to reproduce the results of continuum hydrodynamics exactly. The underlying lattice is the 4D FCHC lattice. This lattice: (1) Permits all integral energies, (2) Has sufficient symmetry to allow for an isotropic stress tensor for each energy individually, (3) Allows interaction amongst all energies, and (4) Has discrete microscopic Galilean invariance, all of which allows the extension of the model to higher-speeds. This lattice is the only regular lattice with these remarkable properties, all of which are required to show that the discreteness artifacts completely disappear from the LGA in the limit of infinite speeds, so that correct continuum hydrodynamic behavior results. The author verifies the removal of the discreteness artifacts from the momentum equation using a decaying shear wave experiment and shows they are still invisible for Mach numbers up to M [approximately].4 beyond the theoretical limit. Flow between flat plates replicated the expected parabolic profile of Poiseuille flow in the mean when started from rest. Two separate measurements of the kinematic viscosity of the fluid (normal pressure drop and the microscopic particle force at the wall) agreed with each other and with the shear wave viscosity to better than 1%. Cylinder flow simulations accurately reproduced drag coefficients and eddy-length to diameter ratios for Re[le]45 to within the error of experimental observation. At higher Reynolds number, Re [approx equal] 65, vortex shedding was observed to occur. CFD results for flow past cylinders at similar Reynolds numbers produce either erroneous results or rely on artificially perturbing the flow to cause phenomena that does not occur naturally in the method.
Houck, E.D.
1994-10-11T23:59:59.000Z
An fluid sampling system allows sampling of radioactive liquid without spillage. A feed tank is connected to a liquid transfer jet powered by a pumping chamber pressurized by compressed air. The liquid is pumped upwardly into a sampling jet of a venturi design having a lumen with an inlet, an outlet, a constricted middle portion, and a port located above the constricted middle portion. The liquid is passed under pressure through the constricted portion causing its velocity to increase and its pressure to be decreased, thereby preventing liquid from escaping. A septum sealing the port can be pierced by a two pointed hollow needle leading into a sample bottle also sealed by a pierceable septum affixed to one end. The bottle is evacuated by flow through the sample jet, cyclic variation in the sampler jet pressure periodically leaves the evacuated bottle with lower pressure than that of the port, thus causing solution to pass into the bottle. The remaining solution in the system is returned to the feed tank via a holding tank. 4 figs.
Houck, Edward D. (Idaho Falls, ID)
1994-01-01T23:59:59.000Z
An fluid sampling system allows sampling of radioactive liquid without spillage. A feed tank is connected to a liquid transfer jet powered by a pumping chamber pressurized by compressed air. The liquid is pumped upwardly into a sampling jet of a venturi design having a lumen with an inlet, an outlet, a constricted middle portion, and a port located above the constricted middle portion. The liquid is passed under pressure through the constricted portion causing its velocity to increase and its pressure to decreased, thereby preventing liquid from escaping. A septum sealing the port can be pierced by a two pointed hollow needle leading into a sample bottle also sealed by a pierceable septum affixed to one end. The bottle is evacuated by flow through the sample jet, cyclic variation in the sampler jet pressure periodically leaves the evacuated bottle with lower pressure than that of the port, thus causing solution to pass into the bottle. The remaining solution in the system is returned to the feed tank via a holding tank.
Michael C. Adams; Greg Nash
2004-03-01T23:59:59.000Z
Geothermal water must be injected back into the reservoir after it has been used for power production. Injection is critical in maximizing the power production and lifetime of the reservoir. To use injectate effectively the direction and velocity of the injected water must be known or inferred. This information can be obtained by using chemical tracers to track the subsurface flow paths of the injected fluid. Tracers are chemical compounds that are added to the water as it is injected back into the reservoir. The hot production water is monitored for the presence of this tracer using the most sensitive analytic methods that are economically feasible. The amount and concentration pattern of the tracer revealed by this monitoring can be used to evaluate how effective the injection strategy is. However, the tracers must have properties that suite the environment that they will be used in. This requires careful consideration and testing of the tracer properties. In previous and parallel investigations we have developed tracers that are suitable from tracing liquid water. In this investigation, we developed tracers that can be used for steam and mixed water/steam environments. This work will improve the efficiency of injection management in geothermal fields, lowering the cost of energy production and increasing the power output of these systems.
Computer Vision in Fluid Mechanics
Aminfar, AmirHessam
2015-01-01T23:59:59.000Z
layers," Journal of Fluid Mechanics, vol. 30, no. 04, pp.M. Princevac, "Fundamental fluid mechanics," 2014. C. W.Computer Vision in Fluid Mechanics A Thesis submitted in
Computer Vision in Fluid Mechanics
Aminfar, AmirHessam
2015-01-01T23:59:59.000Z
layers," Journal of Fluid Mechanics, vol. 30, no. 04, pp.Fundamental fluid mechanics," 2014. C. W. Enderlin, "MacroComputer Vision in Fluid Mechanics A Thesis submitted in
FRACTURING FLUID CHARACTERIZATION FACILITY
Subhash Shah
2000-08-01T23:59:59.000Z
Hydraulic fracturing technology has been successfully applied for well stimulation of low and high permeability reservoirs for numerous years. Treatment optimization and improved economics have always been the key to the success and it is more so when the reservoirs under consideration are marginal. Fluids are widely used for the stimulation of wells. The Fracturing Fluid Characterization Facility (FFCF) has been established to provide the accurate prediction of the behavior of complex fracturing fluids under downhole conditions. The primary focus of the facility is to provide valuable insight into the various mechanisms that govern the flow of fracturing fluids and slurries through hydraulically created fractures. During the time between September 30, 1992, and March 31, 2000, the research efforts were devoted to the areas of fluid rheology, proppant transport, proppant flowback, dynamic fluid loss, perforation pressure losses, and frictional pressure losses. In this regard, a unique above-the-ground fracture simulator was designed and constructed at the FFCF, labeled ''The High Pressure Simulator'' (HPS). The FFCF is now available to industry for characterizing and understanding the behavior of complex fluid systems. To better reflect and encompass the broad spectrum of the petroleum industry, the FFCF now operates under a new name of ''The Well Construction Technology Center'' (WCTC). This report documents the summary of the activities performed during 1992-2000 at the FFCF.
QGP viscosity at RHIC and the LHC - a 2012 status report
Huichao Song
2012-11-26T23:59:59.000Z
In this article, we briefly review the recent progress related to extracting the quark-gluon plasma (QGP) specific shear viscosity from the flow data measured at Relativistic Heavy-Ion Collider (RHIC) and the Large Hadron Collider (LHC).
The effective approach for predicting viscosity of saturated and undersaturated reservoir oil
Kulchanyavivat, Sawin
2006-04-12T23:59:59.000Z
Predicting reservoir oil viscosity with numerical correlation equations using field-measured variables is widely used in the petroleum industry. Most published correlation equations, however, have never profoundly realized the genuine relationship...
Takata, Rosalind (Rosalind Kazuko), 1978-
2006-01-01T23:59:59.000Z
The piston ring-pack contributes approximately 25% of the mechanical losses in an internal combustion engine. Both lubricant viscosity and surface texturing were investigated in an effort to reduce this ring-pack friction ...
The effective approach for predicting viscosity of saturated and undersaturated reservoir oil
Kulchanyavivat, Sawin
2006-04-12T23:59:59.000Z
with creating a large database of pressure-volumetemperature (PVT) reports and screening all possible erroneous data. The relationship between the oil viscosity and other field-measured parameters is intensively analyzed by using theoretical and empirical...
An extension of Pedersen's viscosity model for saturated black oil systems
Adejuwon, Adeyemi
2000-01-01T23:59:59.000Z
when needed for simple regression. We also investigated a functional relationship amongst pressure, volume, temperature (PVT) properties and a set of variables required to describe the viscosity correlation using a nonparametric regression analysis...
Role of viscosity in the accurate prediction of source-terms for high molecular weight substances
Shaikh, Irfan Yusuf
1999-01-01T23:59:59.000Z
This study shows that using better material property predictions results in better source-term modeling for high molecular weight substances. Viscosity, density, and enthalpy are used as a function of process variables, namely, temperature...
Abdullayev, Azer
2009-06-02T23:59:59.000Z
Experimental and analytical studies have been carried out to better understand the effects of additives on viscosity, density and surface tension of intermediate and heavy crude oils. The studies have been conducted for the following oil samples...
Burgess, Ward A.; Tapriyal, Deepak; Morreale, Bryan D.; Soong, Yee; Baled, Hseen; O Enick, Robert M; Wu, Yue; Bamgbade, Babatunde A.; McHugh,Mark A.
2013-12-15T23:59:59.000Z
This research focuses on providing the petroleum reservoir engineering community with robust models of hydrocarbon density and viscosity at the extreme temperature and pressure conditions (up to 533 K and 276 MPa, respectively) characteristic of ultra-deep reservoirs, such as those associated with the deepwater wells in the Gulf of Mexico. Our strategy is to base the volume-translated (VT) Peng–Robinson (PR) and Soave–Redlich–Kwong (SRK) cubic equations of state (EoSs) and perturbed-chain, statistical associating fluid theory (PC-SAFT) on an extensive data base of high temperature (278–533 K), high pressure (6.9–276 MPa) density rather than fitting the models to low pressure saturated liquid density data. This high-temperature, high-pressure (HTHP) data base consists of literature data for hydrocarbons ranging from methane to C{sub 40}. The three new models developed in this work, HTHP VT-PR EoS, HTHP VT-SRK EoS, and hybrid PC-SAFT, yield mean absolute percent deviation values (MAPD) for HTHP hydrocarbon density of ?2.0%, ?1.5%, and <1.0%, respectively. An effort was also made to provide accurate hydrocarbon viscosity models based on literature data. Viscosity values are estimated with the frictional theory (f-theory) and free volume (FV) theory of viscosity. The best results were obtained when the PC-SAFT equation was used to obtain both the attractive and repulsive pressure inputs to f-theory, and the density input to FV theory. Both viscosity models provide accurate results at pressures to 100 MPa but experimental and model results can deviate by more than 25% at pressures above 200 MPa.
Rotational viscometer for high-pressure high-temperature fluids
Carr, Kenneth R. (Knoxville, TN)
1985-01-01T23:59:59.000Z
The invention is a novel rotational viscometer which is well adapted for use with fluids at high temperatures and/or pressures. In one embodiment, the viscometer includes a substantially non-magnetic tube having a closed end and having an open end in communication with a fluid whose viscosity is to be determined. An annular drive magnet is mounted for rotation about the tube. The tube encompasses and supports a rotatable shaft assembly which carries a rotor, or bob, for insertion in the fluid. Affixed to the shaft are (a) a second magnet which is magnetically coupled to the drive magnet and (b) a third magnet. In a typical operation, the drive magnet is rotated to turn the shaft assembly while the shaft rotor is immersed in the fluid. The viscous drag on the rotor causes the shaft assembly to lag the rotation of the drive magnet by an amount which is a function of the amount of viscous drag. A first magnetic pickup generates a waveform whose phase is a function of the angular position of the drive magnet. A second magnetic pickup generates a waveform whose phase is a function of the angular position of the third magnet. An output is generated indicative of the phase difference between the two waveforms.
Numerical implication of Riemann problem theory for fluid dynamics
Menikoff, R.
1988-01-01T23:59:59.000Z
The Riemann problem plays an important role in understanding the wave structure of fluid flow. It is also crucial step in some numerical algorithms for accurately and efficiently computing fluid flow; Godunov method, random choice method, and from tracking method. The standard wave structure consists of shock and rarefaction waves. Due to physical effects such as phase transitions, which often are indistinguishable from numerical errors in an equation of state, anomalkous waves may occur, ''rarefaction shocks'', split waves, and composites. The anomalous waves may appear in numerical calculations as waves smeared out by either too much artificial viscosity or insufficient resolution. In addition, the equation of state may lead to instabilities of fluid flow. Since these anomalous effects due to the equation of state occur for the continuum equations, they can be expected to occur for all computational algorithms. The equation of state may be characterized by three dimensionless variables: the adiabatic exponent ..gamma.., the Grueneisen coefficient GAMMA, and the fundamental derivative G. The fluid flow anomalies occur when inequalities relating these variables are violated. 18 refs.
A study of the mixing viscosity of asphalt in hot-mix production
Khan, Md. Musharraf Hossain
1961-01-01T23:59:59.000Z
of many 85-100 3 penetration asphalts. It was concluded that although asphalts of certain grade but from different sources usually show identical viscosities; occasionally, others have shown entirely different values. Fink and Lettier concluded..., Vol. 30, No. 9, pp. 197-207, August, 1959. 4 Fink, D. F. and Lettier, J. A. , "Viscosity Effects in the Marshall Stability Tests, " Proc. Assoc. Asphalt Paving Tech. , Vol. 20, pp. 246-269, February, 1951. 5 Benson, Fred J. , "Appraisal of Several...
On the "viscosity maximum" during the uniaxial extension of a low density polyethylene
Teodor I. Burghelea; Zdenek Stary; Helmut Muenstedt
2010-01-13T23:59:59.000Z
An experimental investigation of the viscosity overshoot phenomenon observed during uniaxial extension of a low density polyethylene is pre- sented. For this purpose, traditional integral viscosity measurements on a Muenstedt type extensional rheometer are combined with local mea- surements based on the in-situ visualization of the sample under exten- sion. For elongational experiments at constant strain rates within a wide range of Weissenberg numbers (Wi), three distinct deformation regimes are identified. Corresponding to low values of Wi (regime I), the tensile stress displays a broad maximum. This maximum can be explained by simple mathematical arguments as a result of low deformation rates and it should not be confused with the viscosity overshoot phenomenon. Corre- sponding to intermediate values of Wi (regime II), a local maximum of the integral extensional viscosity is systematically observed. However, within this regime, the local viscosity measurements reveal no maximum, but a plateau. Careful inspection of the images of samples within this regime shows that, corresponding to the maximum of the integral viscosity, sec- ondary necks develop along the sample. The emergence of a maximum of the integral elongational viscosity is thus related to the distinct in- homogeneity of deformation states and is not related to the rheological properties of the material. In the fast stretching limit (high Wi, regime III), the overall geometric uniformity of the sample is well preserved, no secondary necks are observed and both the integral and the local transient elongational viscosity show no maximum. A detailed comparison of the experimental findings with results from literature is presented.
Multiphase fluid characterization system
Sinha, Dipen N.
2014-09-02T23:59:59.000Z
A measurement system and method for permitting multiple independent measurements of several physical parameters of multiphase fluids flowing through pipes are described. Multiple acoustic transducers are placed in acoustic communication with or attached to the outside surface of a section of existing spool (metal pipe), typically less than 3 feet in length, for noninvasive measurements. Sound speed, sound attenuation, fluid density, fluid flow, container wall resonance characteristics, and Doppler measurements for gas volume fraction may be measured simultaneously by the system. Temperature measurements are made using a temperature sensor for oil-cut correction.
Supercritical fluid extraction
Wai, Chien M. (Moscow, ID); Laintz, Kenneth (Pullman, WA)
1994-01-01T23:59:59.000Z
A method of extracting metalloid and metal species from a solid or liquid material by exposing the material to a supercritical fluid solvent containing a chelating agent. The chelating agent forms chelates that are soluble in the supercritical fluid to allow removal of the species from the material. In preferred embodiments, the extraction solvent is supercritical carbon dioxide and the chelating agent is a fluorinated or lipophilic crown ether or fluorinated dithiocarbamate. The method provides an environmentally benign process for removing contaminants from industrial waste without using acids or biologically harmful solvents. The chelate and supercritical fluid can be regenerated, and the contaminant species recovered, to provide an economic, efficient process.
The effect of various mixers on the viscosity and flow properties of an oil well drilling fluid
Spannagel, Johnny Allen
1957-01-01T23:59:59.000Z
. s Mixezs 16 10. The Effect of Various Mixers on the Farm V-G Meter Reading When Water is Added to Reduce the Density to Its Original Value . 18 11. The Effect of Various Mixers on the Farm V-G Meter Re ading When Water is Added to Reduce the Density.... The Effect of Adding Water to Reduce the Density of Its Original Value 27 IV. The Effect of Aging on a B entonite Mud. 2B ABSTRACT This thesis presents a comparison of some of the common labora- tory mixers for use in agitating drilling muds to a mixer...
The effect of various mixers on the viscosity and flow properties of an oil well drilling fluid
Spannagel, Johnny Allen
1957-01-01T23:59:59.000Z
. The Effect of Adding Water to Reduce the Density of Its Original Value 27 IV. The Effect of Aging on a B entonite Mud. 2B ABSTRACT This thesis presents a comparison of some of the common labora- tory mixers for use in agitating drilling muds to a mixer... designed as a part of this research to overcome evaporation of the water phase of the mud. The latter is termed the Lo-Speed mixer. The mud was agitated at speeds of 400, 610, and 1, 500 rpm in the Lo-Speed mixer, 15, 000 rpm in the Waring Blendor...
Shear viscosity $?$ to electric conductivity $?_{el}$ ratio for the Quark-Gluon Plasma
A. Puglisi; S. Plumari; V. Greco
2015-05-04T23:59:59.000Z
The transport coefficients of strongly interacting matter are currently subject of intense theoretical and phenomenological studies due to their relevance for the characterization of the quark-gluon plasma produced in ultra relativistic heavy-ion collisions (uRHIC). We discuss the connection between the shear viscosity to entropy density ratio, $\\eta/s$, and the electric conductivity, $\\sigma_{el}$. Once the relaxation time is tuned to have a minimum value of $\\eta/s=1/4\\pi$ near the critical temperature $T_c$, one simultaneously predicts $\\sigma_{el}/T$ very close to recent lQCD data. More generally, we discuss why the ratio of $(\\eta/s)/(\\sigma_{el}/T)$ supplies a measure of the quark to gluon scattering rates whose knowledge would allow to significantly advance in the understanding of the QGP phase. We also predict that $(\\eta/s)/(\\sigma_{el}/T)$, independently on the running coupling $\\alpha_s(T)$, should increase up to about $\\sim 20$ for $T \\rightarrow T_c$, while it goes down to a nearly flat behavior around $\\simeq 4$ for $T \\geq 4\\, T_c$. Therefore we in general predict a stronger T dependence of $\\sigma_{el}/T$ with respect to $\\eta/s$ that in a quasiparticle approach is constrained by lQCD thermodynamics. A conformal theory, instead, predicts a similar T dependence of $\\eta/s$ and $\\sigma_{el}/T$.
Shear Banding of Complex Fluids
Thibaut Divoux; Marc A. Fardin; Sébastien Manneville; Sandra Lerouge
2015-03-13T23:59:59.000Z
Even in simple geometries many complex fluids display non-trivial flow fields, with regions where shear is concentrated. The possibility for such shear banding has been known since several decades, but the recent years have seen an upsurge of studies offering an ever more precise understanding of the phenomenon. The development of new techniques to probe the flow on multiple scales and with increasing spatial and temporal resolution has opened the possibility for a synthesis of the many phenomena that could only have been thought of separately before. In this review, we bring together recent research on shear banding in polymeric and on soft glassy materials, and highlight their similarities and disparities.
Semans, J.P.; Johnson, P.G.; LeBoeuf, R.F. Jr.; Kromka, J.A.; Goron, R.H.; Hay, G.D.
1991-04-30T23:59:59.000Z
This invention, a trainer mounted and housed within a mobile console, is used to teach and reinforce fluid principles to students. The system trainer has two centrifugal pumps, each driven by a corresponding two-speed electric motor. The motors are controlled by motor controllers for operating the pumps to circulate the fluid stored within a supply tank through a closed system. The pumps may be connected in series or in parallel. A number of valves are also included within the system to effect different flow paths for the fluid. In addition, temperature and pressure sensing instruments are installed throughout the closed system for measuring the characteristics of the fluid, as it passes through the different valves and pumps. These measurements are indicated on a front panel mounted to the console, as a teaching aid, to allow the students to observe the characteristics of the system.
Brenner, Howard
This paper presents a unified theory of phoretic phenomena in single-component fluids. Simple formulas are given for the phoretic velocities of small inert force-free non-Brownian particles migrating through otherwise ...
Semans, Joseph P. (Uniontown, PA); Johnson, Peter G. (Pittsburgh, PA); LeBoeuf, Jr., Robert F. (Clairton, PA); Kromka, Joseph A. (Idaho Falls, ID); Goron, Ronald H. (Connellsville, PA); Hay, George D. (Venetia, PA)
1993-01-01T23:59:59.000Z
A trainer, mounted and housed within a mobile console, is used to teach and reinforce fluid principles to students. The system trainer has two centrifugal pumps, each driven by a corresponding two-speed electric motor. The motors are controlled by motor controllers for operating the pumps to circulate the fluid stored within a supply tank through a closed system. The pumps may be connected in series or in parallel. A number of valves are also included within the system to effect different flow paths for the fluid. In addition, temperature and pressure sensing instruments are installed throughout the closed system for measuring the characteristics of the fluid, as it passes through the different valves and pumps. These measurements are indicated on a front panel mounted to the console, as a teaching aid, to allow the students to observe the characteristics of the system.
West, Phillip B. (Idaho Falls, ID)
2006-01-17T23:59:59.000Z
A method and apparatus suitable for coupling seismic or other downhole sensors to a borehole wall in high temperature and pressure environments. In one embodiment, one or more metal bellows mounted to a sensor module are inflated to clamp the sensor module within the borehole and couple an associated seismic sensor to a borehole wall. Once the sensing operation is complete, the bellows are deflated and the sensor module is unclamped by deflation of the metal bellows. In a further embodiment, a magnetic drive pump in a pump module is used to supply fluid pressure for inflating the metal bellows using borehole fluid or fluid from a reservoir. The pump includes a magnetic drive motor configured with a rotor assembly to be exposed to borehole fluid pressure including a rotatable armature for driving an impeller and an associated coil under control of electronics isolated from borehole pressure.
Circulating Fluid Bed Combustor
Fraley, L. D.; Do, L. N.; Hsiao, K. H.
1982-01-01T23:59:59.000Z
The circulating bed combustor represents an alternative concept of burning coal in fluid bed technology, which offers distinct advantages over both the current conventional fluidized bed combustion system and the pulverized coal boilers equipped...
Oborny, Michael C. (Albuquerque, NM); Paul, Phillip H. (Livermore, CA); Hencken, Kenneth R. (Pleasanton, CA); Frye-Mason, Gregory C. (Cedar Crest, NM); Manginell, Ronald P. (Albuquerque, NM)
2001-01-01T23:59:59.000Z
A valve for controlling fluid flows. This valve, which includes both an actuation device and a valve body provides: the ability to incorporate both the actuation device and valve into a unitary structure that can be placed onto a microchip, the ability to generate higher actuation pressures and thus control higher fluid pressures than conventional microvalves, and a device that draws only microwatts of power. An electrokinetic pump that converts electric potential to hydraulic force is used to operate, or actuate, the valve.
Ultrarelativistic fluid dynamics
David W. Neilsen; Matthew W. Choptuik
1999-04-20T23:59:59.000Z
This is the first of two papers examining the critical collapse of spherically symmetric perfect fluids with the equation of state P = (Gamma -1)rho. Here we present the equations of motion and describe a computer code capable of simulating the extremely relativistic flows encountered in critical solutions for Gamma <= 2. The fluid equations are solved using a high-resolution shock-capturing scheme based on a linearized Riemann solver.
CSE Master Specialization Fluid Dynamics
Lang, Annika
CSE Master Specialization Fluid Dynamics Course Semester Fluid Dynamics II HS Quantitative Flow Energie- und Verfahrenstechnik FS Biofluiddynamics FS #12;CSE in Fluid Dynamics: Very large high in Fluid Dynamics: Physiology of the inner ear MicroCT imaging Multilayer MFS for Stokes flow simulations
MQSN -Fluid queues Werner Scheinhardt
Boucherie, Richard J.
of Markov fluid sources is again Markov fluid. This idea can be formalized using Kronecker sums. #12;Burst information captured by number of sources that is on! #12;Burst-level models: Markov fluid Special case: sources are identical, for instance two-state on-off Markov-fluid sources. All state information captured
Lecture notes Introductory fluid mechanics
Malham, Simon J.A.
Lecture notes Introductory fluid mechanics Simon J.A. Malham Simon J.A. Malham (15th September 2014 of fluid mechanics and along the way see lots of interesting applications. 2 Fluid flow, the Continuum are generally incompressible--a feature essential to all modern car braking mechanisms. Fluids can be further
Tailored Working Fluids for Enhanced Binary Geothermal Power Plants
Broader source: Energy.gov [DOE]
DOE Geothermal Program Peer Review 2010 - Presentation. Project Objective: To improve the utilization of available energy in geothermal resources and increase the energy conversion efficiency of systems employed by a) tailoring the subcritical and/or supercritical glide of enhanced working fluids to best match thermal resources, and b) identifying appropriate thermal system and component designs for the down-selected working fluids.
Fluorescent fluid interface position sensor
Weiss, Jonathan D.
2004-02-17T23:59:59.000Z
A new fluid interface position sensor has been developed, which is capable of optically determining the location of an interface between an upper fluid and a lower fluid, the upper fluid having a larger refractive index than a lower fluid. The sensor functions by measurement, of fluorescence excited by an optical pump beam which is confined within a fluorescent waveguide where that waveguide is in optical contact with the lower fluid, but escapes from the fluorescent waveguide where that waveguide is in optical contact with the upper fluid.
Viscosity of neutron star matter and $r$-modes in rotating pulsars
E. E. Kolomeitsev; D. N. Voskresensky
2015-02-21T23:59:59.000Z
We study viscosity of the neutron star matter and $r$-mode instability in rotating neutron stars. Contributions to the shear and bulk viscosities from various processes are calculated with account of in-medium modifications of the nucleon-nucleon interaction. A softening of the pion mode and a possibility of the pion condensation are included. The nucleon pairing is incorporated. In the shear viscosity we include the lepton contribution calculated with account of the Landau damping in the photon exchange, the nucleon contribution described by the medium-modified one pion exchange, and other terms, such as the novel phonon contribution in the 1S$_0$ superfluid neutron phase, and the neutrino term in the neutrino opacity region. The nucleon shear viscosity depends on the density rather moderately and proves to be much less than the lepton term. Among the terms contributing to the bulk viscosity, the term from the medium modified Urca reactions possesses strongest density dependence because of the pion softening. Contributions to the bulk viscosity arising from other reactions induced by charged weak currents are included. The radiative bulk viscosity induced by charged and neutral weak currents in the region of the neutrino transparency of the star is also calculated with account for in-medium effects. The computed frequency boundary of the $r$-mode stability for the stars with the mass $\\ge 1.8 M_{\\odot}$ proves to be above the frequencies of all rotating young pulsars. To explain the stability of rapid rotation of old pulsars in X-ray binaries we propose a novel efficient mechanism associated with appearance of condensates of low-lying modes of bosonic excitations with finite momentum and/or with an enhancement of the inhomogeneous pion/kaon condensates in some parts of the star, if the angular velocity exceeds a critical value.
Fluid driven recipricating apparatus
Whitehead, John C. (Davis, CA)
1997-01-01T23:59:59.000Z
An apparatus comprising a pair of fluid driven pump assemblies in a back-to-back configuration to yield a bi-directional pump. Each of the pump assemblies includes a piston or diaphragm which divides a chamber therein to define a power section and a pumping section. An intake-exhaust valve is connected to each of the power sections of the pump chambers, and function to direct fluid, such as compressed air, into the power section and exhaust fluid therefrom. At least one of the pistons or diaphragms is connected by a rod assembly which is constructed to define a signal valve, whereby the intake-exhaust valve of one pump assembly is controlled by the position or location of the piston or diaphragm in the other pump assembly through the operation of the rod assembly signal valve. Each of the pumping sections of the pump assemblies are provided with intake and exhaust valves to enable filling of the pumping section with fluid and discharging fluid therefrom when a desired pressure has been reached.
Fluid driven reciprocating apparatus
Whitehead, J.C.
1997-04-01T23:59:59.000Z
An apparatus is described comprising a pair of fluid driven pump assemblies in a back-to-back configuration to yield a bi-directional pump. Each of the pump assemblies includes a piston or diaphragm which divides a chamber therein to define a power section and a pumping section. An intake-exhaust valve is connected to each of the power sections of the pump chambers, and function to direct fluid, such as compressed air, into the power section and exhaust fluid therefrom. At least one of the pistons or diaphragms is connected by a rod assembly which is constructed to define a signal valve, whereby the intake-exhaust valve of one pump assembly is controlled by the position or location of the piston or diaphragm in the other pump assembly through the operation of the rod assembly signal valve. Each of the pumping sections of the pump assemblies are provided with intake and exhaust valves to enable filling of the pumping section with fluid and discharging fluid therefrom when a desired pressure has been reached. 13 figs.
Bulk viscosity, particle spectra and flow in heavy-ion collisions
Kevin Dusling; Thomas Schaefer
2012-01-11T23:59:59.000Z
We study the effects of bulk viscosity on pT spectra and elliptic flow in heavy ion collisions. For this purpose we compute the dissipative correction df to the single particle distribution functions in leading-log QCD, and in several simplified models. We consider, in particular, the relaxation time approximation and a kinetic model for the hadron resonance gas. We implement these distribution functions in a hydrodynamic simulation of Au + Au collisions at RHIC. We find significant corrections due to bulk viscosity in hadron pT spectra and the differential elliptic flow parameter v2(pT). These corrections are dominated by viscous corrections to the distribution function. We find that the relation between df and the bulk viscosity is different in the quark gluon plasma and hadronic phases. Reliable bounds on the bulk viscosity require accurate calculations of df in a hadronic resonance gas. Based on v2 spectra at RHIC we conservatively estimate zeta/s viscosity on the pT integrated v2 are small.
On the abrupt growth dynamics of nonlinear resistive tearing mode and the viscosity effects
Ali, A.; Li, Jiquan, E-mail: lijq@energy.kyoto-u.ac.jp [Graduate School of Energy Science, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Kishimoto, Y. [Graduate School of Energy Science, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan)
2014-05-15T23:59:59.000Z
The nonlinear evolution of the resistive tearing mode exhibits an abrupt growth after an X-point collapse once the magnetic island exceeds a certain critical width ??w{sub c} for large instability parameter ??, leading to a current sheet formation [N. F. Loureiro et al., Phys. Rev. Lett. 95, 235003 (2005)]. In this work, we investigate the underlying mechanism of the X-point collapse as well as the current sheet formation including the viscosity effects, based on a secondary instability analysis. The secondary instability is excited due to the quasilinear current modification by the zonal current. In particular, it is identified that the current peaking effect is plausibly responsible for the onset of the X-point collapse and the current sheet formation, leading to the explosive growth of reconnected flux. In the presence of finite viscosity, the ??w{sub c} scaling with the resistivity gets modified. A transition behavior is revealed at P{sub r}?1 for the viscosity dependence of ??w{sub c} and the linear tearing instability. However, the explosive growth seems to be independent of the viscosity in the magnetic Prandtl number P{sub r}<1 regime, while large viscosity plays a strong dissipation role.
Shear viscosity of the quark-gluon plasma in a kinetic theory approach
Puglisi, A.; Plumari, S.; Scardina, F.; Greco, V. [Department of Physics and Astronomy, University of Catania, Via S. Sofia 64, I-95125 Catania, Italy and Laboratorio Nazionale del Sud, INFN-LNS, Via S. Sofia 63, I-95125 Catania (Italy)
2014-05-09T23:59:59.000Z
One of the main results of heavy ions collision (HIC) at relativistic energy experiments is the very small shear viscosity to entropy density ratio of the Quark-Gluon Plasma, close to the conjectured lower bound ?/s=1/4? for systems in the infinite coupling limit. Transport coefficients like shear viscosity are responsible of non-equilibrium properties of a system: Green-Kubo relations give us an exact expression to compute these coefficients. We compute shear viscosity numerically using Green-Kubo relation in the framework of Kinetic Theory solving the relativistic transport Boltzmann equation in a finite box with periodic boundary conditions. We investigate a system of particles interacting via anisotropic and energy dependent cross-section in the range of temperature of interest for HIC. Green-Kubo results are in agreement with Chapman-Enskog approximation while Relaxation Time approximation can underestimates the viscosity of a factor 2. The correct analytic formula for shear viscosity can be used to develop a transport theory with a fixed ?/s and have a comparison with physical observables like elliptic flow.
Dynamics of a confined dusty fluid in a sheared ion flow
Laishram, Modhuchandra; Sharma, Devendra; Kaw, Predhiman K. [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India)
2014-07-15T23:59:59.000Z
Dynamics of an isothermally driven dust fluid is analyzed which is confined in an azimuthally symmetric cylindrical setup by an effective potential and is in equilibrium with an unconfined sheared flow of a streaming plasma. Cases are analyzed where the confining potential constitutes a barrier for the driven fluid, limiting its spatial extension and boundary velocity. The boundary effects entering the formulation are characterized by applying the appropriate boundary conditions and a range of solutions exhibiting single and multiple vortex are obtained. The equilibrium solutions considered in the cylindrical setup feature a transition from single to multiple vortex state of the driven flow. Effects of (i) the variation in dust viscosity, (ii) coupling between the driving and the driven fluid, and (iii) a friction determining the equilibrium dynamics of the driven system are characterized.
Theory of wetting-induced fluid entrainment by advancing contact lines on dry surfaces
Rodrigo Ledesma-Aguilar; Aurora Hernández-Machado; Ignacio Pagonabarraga
2013-06-11T23:59:59.000Z
We report on the onset of fluid entrainment when a contact line is forced to advance over a dry solid of arbitrary wettability. We show that entrainment occurs at a critical advancing speed beyond which the balance between capillary, viscous and contact line forces sustaining the shape of the interface is no longer satisfied. Wetting couples to the hydrodynamics by setting both the morphology of the interface at small scales and the viscous friction of the front. We find that the critical deformation that the interface can sustain is controlled by the friction at the contact line and the viscosity contrast between the displacing and displaced fluids, leading to a rich variety of wetting-entrainment regimes. We discuss the potential use of our theory to measure contact-line forces using atomic force microscopy, and to study entrainment under microfluidic conditions exploiting colloid-polymer fluids of ultra-low surface tension.
Universal fluid droplet ejector
Lee, E.R.; Perl, M.L.
1999-08-24T23:59:59.000Z
A droplet generator comprises a fluid reservoir having a side wall made of glass or quartz, and an end cap made from a silicon plate. The end cap contains a micromachined aperture through which the fluid is ejected. The side wall is thermally fused to the end cap, and no adhesive is necessary. This means that the fluid only comes into contact with the side wall and the end cap, both of which are chemically inert. Amplitudes of drive pulses received by reservoir determine the horizontal displacements of droplets relative to the ejection aperture. The drive pulses are varied such that the dropper generates a two-dimensional array of vertically-falling droplets. Vertical and horizontal inter-droplet spacings may be varied in real time. Applications include droplet analysis experiments such as Millikan fractional charge searches and aerosol characterization, as well as material deposition applications. 8 figs.
Gray, Harold E. (Las Vegas, NV); McLaurin, Felder M. (Las Vegas, NV); Ortiz, Monico (Las Vegas, NV); Huth, William A. (Las Vegas, NV)
1996-01-01T23:59:59.000Z
A device or system for monitoring for the presence of leaks from a hazardous fluid is disclosed which uses two electrodes immersed in deionized water. A gas is passed through an enclosed space in which a hazardous fluid is contained. Any fumes, vapors, etc. escaping from the containment of the hazardous fluid in the enclosed space are entrained in the gas passing through the enclosed space and transported to a closed vessel containing deionized water and two electrodes partially immersed in the deionized water. The electrodes are connected in series with a power source and a signal, whereby when a sufficient number of ions enter the water from the gas being bubbled through it (indicative of a leak), the water will begin to conduct, thereby allowing current to flow through the water from one electrode to the other electrode to complete the circuit and activate the signal.
The dilute Fermi gas is the most "perfect fluid" in Nature
Gabriel Wlaz?owski; Wei Quan; Aurel Bulgac
2015-07-03T23:59:59.000Z
We present an ab initio calculation of the shear viscosity as a function of interaction strength in a two-component unpolarized Fermi gas near the unitary limit, within a finite temperature quantum Monte Carlo (QMC) framework and using the Kubo linear-response formalism. The shear viscosity decreases as we tune the interaction strength $1/ak_F$ from the Bardeen-Cooper-Schrieffer (BCS) side of the Feshbach resonance towards Bose-Einstein condensation (BEC) limit and it acquires the smallest value for $1/ak_F\\approx0.4$, with a minimum value of $\\left . \\frac{\\eta}{s}\\right |_{min} \\approx 0.2 \\frac{\\hbar}{k_B}$, which is about twice as small than the value reported for experiments in quark-gluon plasma $\\left . \\frac{\\eta}{s}\\right |_{QGP} \\lesssim 0.4\\frac{\\hbar}{k_B}$. The Fermi gas near unitarity thus emerges as the most "perfect fluid" so far in Nature.
Reacting fluids in the expanding Universe: A new mechanism for entropy production
Winfried Zimdahl
1997-02-07T23:59:59.000Z
It is shown that two reacting cosmological fluids, each of them perfect on its own, which exchange energy and momentum without preserving particle numbers, give rise to an entropy producing `reactive' bulk stress of the system as a whole, as soon as the detailed balance between decay and inverse decay processes is perturbed. This demonstrates explicitly that particle generation is dynamically equivalent to an effective bulk pressure. We derive a semiquantitative formula for the corresponding new kinetic coefficient and evaluate the latter for the out-of-equilibrium decay of heavy, nonrelativistic particles into radiation. It turns out that the associated reactive bulk viscosity may be more than one order of magnitude larger than the conventional bulk viscosity, calculated, e.g., in radiative hydrodynamics.
Structure evolution in electrorheological fluids flowing through microchannels
, including valves2,3 , clutches4 and shock absorbers5 . Recently, custom-formulated ER fluids have been that the increasing shear stress passes through three sequential stages17 . In the first stage, the shear stress
Souza, R.F. de [Departamento de Física, Universidade Estadual de Maringá, Avenida Colombo 5790, 87020 - 900 Maringá –PR (Brazil); Yang, D.-Ke [Chemical Physics Interdisciplinary Program and Liquid Crystal Institute, Kent State University, Kent, OH 44242 (United States); Lenzi, E.K.; Evangelista, L.R. [Departamento de Física, Universidade Estadual de Maringá, Avenida Colombo 5790, 87020 - 900 Maringá –PR (Brazil); Zola, R.S., E-mail: rzola@utfpr.edu.br [Departamento de Física, Universidade Estadual de Maringá, Avenida Colombo 5790, 87020 - 900 Maringá –PR (Brazil); Universidade Tecnologica Federal do Paraná, Rua Marcilio Dias 635, 86812-460 Apucarana, Paraná (Brazil)
2014-07-15T23:59:59.000Z
An analytical expression for the relaxation time of a nematic liquid crystal is obtained for the first time by considering the influence of surface viscosity, anchoring energy strength and cell gap, validated numerically by using the so-called relaxation method. This general equation for the molecular response time (?{sub 0}) was derived for a vertical aligned cell and by solving an eigenvalue equation coming from the usual balance of torque equation in the Derzhanskii and Petrov formulation, recovering the usual equations in the appropriate limit. The results show that ??d{sup b}, where b=2 is observed only for strongly anchored cells, while for moderate to weak anchored cells, the exponent lies between 1 and 2, depending on both, surface viscosity and anchoring strength. We found that the surface viscosity is important when calculating the response time, specially for thin cells, critical for liquid crystal devices. The surface viscosity’s effect on the optical response time with pretilt is also explored. Our results bring new insights about the role of surface viscosity and its effects in applied physics. - Highlights: • The relaxation of nematic liquid crystals is calculated by taking the surface viscosity into account. • An analytical expression for the relaxation time depending on surface viscosity, anchoring strength and cell gap is obtained. • The results are numerically verified. • Surface viscosity is crucial for thin and weak anchored cells. • The effect on optical time and pretilt angle is also studied.
Measurements of velocity shear and ion viscosity profile in a magnetohydrodynamic plasma jet
Dorf, L. A.; Intrator, T.; Sun, X.; Hendryx, J.; Wurden, G. A.; Furno, I; Lapenta, G. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
2010-10-15T23:59:59.000Z
Time-dependent, two-dimensional profiles of the axial flow velocity, density, electron temperature, and magnetic field components are measured at two axial locations in a screw pinch plasma column of the reconnection scaling experiment. The results show that the ion momentum flux for a given column radius is dissipated by the ion-ion Coulomb scattering viscosity due to a significant radial shear of the axial velocity. By comparing the terms of the magnetohydrodynamic momentum balance equation, radial profile of ion viscosity is determined. Chord-integrated ion temperature measurements performed at several radial locations using Doppler broadening spectroscopy show ion temperature of about 1 eV. Measured ion viscosity agrees within a factor of 2 with the classical Braginskii expectations.
Viscosity of gauge theory plasma with a chemical potential from AdS/CFT correspondence
Kengo Maeda; Makoto Natsuume; Takashi Okamura
2006-03-23T23:59:59.000Z
We compute the strong coupling limit of the shear viscosity for the N=4 super-Yang-Mill theory with a chemical potential. We use the five-dimensional Reissner-Nordstrom-anti-deSitter black hole, so the chemical potential is the one for the R-charges U(1)_R^3. We compute the quasinormal frequencies of the gravitational and electromagnetic vector perturbations in the background numerically. This enables one to explicitly locate the diffusion pole for the shear viscosity. The ratio of the shear viscosity eta to the entropy density s is eta/s=1/(4pi) within numerical errors, which is the same result as the one without chemical potential.
Ultrasonic fluid densitometry and densitometer
Greenwood, Margaret S. (Richland, WA); Lail, Jason C. (Conover, NC)
1998-01-01T23:59:59.000Z
The present invention is an ultrasonic fluid densitometer that uses a material wedge having an acoustic impedance that is near the acoustic impedance of the fluid, specifically less than a factor of 11 greater than the acoustic impedance of the fluid. The invention also includes a wedge having at least two transducers for transmitting and receiving ultrasonic signals internally reflected within the material wedge. Density of a fluid is determined by immersing the wedge into the fluid and measuring reflection of ultrasound at the wedge-fluid interface.
Ultrasonic fluid densitometry and densitometer
Greenwood, M.S.; Lail, J.C.
1998-01-13T23:59:59.000Z
The present invention is an ultrasonic fluid densitometer that uses a material wedge having an acoustic impedance that is near the acoustic impedance of the fluid, specifically less than a factor of 11 greater than the acoustic impedance of the fluid. The invention also includes a wedge having at least two transducers for transmitting and receiving ultrasonic signals internally reflected within the material wedge. Density of a fluid is determined by immersing the wedge into the fluid and measuring reflection of ultrasound at the wedge-fluid interface. 6 figs.
The Fluid Nature of Quark-Gluon Plasma
W. A. Zajc
2008-02-25T23:59:59.000Z
Collisions of heavy nuclei at very high energies offer the exciting possibility of experimentally exploring the phase transformation from hadronic to partonic degrees of freedom which is predicted to occur at several times normal nuclear density and/or for temperatures in excess of $\\sim 170$ MeV. Such a state, often referred to as a quark-gluon plasma, is thought to have been the dominant form of matter in the universe in the first few microseconds after the Big Bang. Data from the first five years of heavy ion collisions of Brookhaven National Laboratory's Relativistic Heavy Ion Collider (RHIC) clearly demonstrate that these very high temperatures and densities have been achieved. While there are strong suggestions of the role of quark degrees of freedom in determining the final-state distributions of the produced matter, there is also compelling evidence that the matter does {\\em not} behave as a quasi-ideal state of free quarks and gluons. Rather, its behavior is that of a dense fluid with very low kinematic viscosity exhibiting strong hydrodynamic flow and nearly complete absorption of high momentum probes. The current status of the RHIC experimental studies is presented, with a special emphasis on the fluid properties of the created matter, which may in fact be the most perfect fluid ever studied in the laboratory.
TRACING FLUID SOURCES IN THE COSO GEOTHERMAL SYSTEM USING FLUID...
FLUID-INCLUSION GAS CHEMISTRY Jump to: navigation, search OpenEI Reference LibraryAdd to library Conference Proceedings: TRACING FLUID SOURCES IN THE COSO GEOTHERMAL SYSTEM USING...
Influence of Fluid Velocity and Cell Concentration on the Transport of
Influence of Fluid Velocity and Cell Concentration on the Transport of Motile and Nonmotile, Pennsylvania 16802 The effect of fluid velocity on the transport of motile and nonmotile bacteria was studied fluid velocity in a porous medium increases the number of collisions of passive colloids with particles
The Mechanical Coupling of Fluid-Filled Granular Material Under Shear L. GOREN,1,2
Einat, Aharonov
The Mechanical Coupling of Fluid-Filled Granular Material Under Shear L. GOREN,1,2 E. AHARONOV,1 D. SPARKS,3 and R. TOUSSAINT 4 Abstract--The coupled mechanics of fluid-filled granular media controls of these geosystems increases. Despite the great importance of the coupled mechanics of grainfluid systems, the basic
Transport properties of the fluid produced at RHIC
Rajeev S. Bhalerao
2010-03-17T23:59:59.000Z
It is by now well known that the relativistic heavy-ion collisions at RHIC, BNL have produced a strongly interacting fluid with remarkable properties, among them the lowest ever observed ratio of the coefficient of shear viscosity to entropy density. Arguments based on ideas from the String Theory, in particular the AdS/CFT correspondence, led to the conjecture --- now known to be violated --- that there is an absolute lower limit $1/4 \\pi$ on the value of this ratio. Causal viscous hydrodynamics calculations together with the RHIC data have put an upper limit on this ratio, a small multiple of $1/4 \\pi$, in the relevant temperature regime. Less well-determined is the ratio of the coefficient of bulk viscosity to entropy density. These transport coefficients have also been studied nonperturbatively in the lattice QCD framework, and perturbatively in the limit of high-temperature QCD. Another interesting transport coefficient is the coefficient of diffusion which is also being studied in this context. I review some of these recent developments and then discuss the opportunities presented by the anticipated LHC data, for the general nuclear physics audience.
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.
EXPERIMENTAL BUBBLE FORMATION IN A LARGE SCALE SYSTEM FOR NEWTONIAN AND NONNEWTONIAN FLUIDS
Leishear, R; Michael Restivo, M
2008-06-26T23:59:59.000Z
The complexities of bubble formation in liquids increase as the system size increases, and a photographic study is presented here to provide some insight into the dynamics of bubble formation for large systems. Air was injected at the bottom of a 28 feet tall by 30 inch diameter column. Different fluids were subjected to different air flow rates at different fluid depths. The fluids were water and non-Newtonian, Bingham plastic fluids, which have yield stresses requiring an applied force to initiate movement, or shearing, of the fluid. Tests showed that bubble formation was significantly different in the two types of fluids. In water, a field of bubbles was formed, which consisted of numerous, distributed, 1/4 to 3/8 inch diameter bubbles. In the Bingham fluid, large bubbles of 6 to 12 inches in diameter were formed, which depended on the air flow rate. This paper provides comprehensive photographic results related to bubble formation in these fluids.
Relativistic viscoelastic fluid mechanics
Masafumi Fukuma; Yuho Sakatani
2011-09-01T23:59:59.000Z
A detailed study is carried out for the relativistic theory of viscoelasticity which was recently constructed on the basis of Onsager's linear nonequilibrium thermodynamics. After rederiving the theory using a local argument with the entropy current, we show that this theory universally reduces to the standard relativistic Navier-Stokes fluid mechanics in the long time limit. Since effects of elasticity are taken into account, the dynamics at short time scales is modified from that given by the Navier-Stokes equations, so that acausal problems intrinsic to relativistic Navier-Stokes fluids are significantly remedied. We in particular show that the wave equations for the propagation of disturbance around a hydrostatic equilibrium in Minkowski spacetime become symmetric hyperbolic for some range of parameters, so that the model is free of acausality problems. This observation suggests that the relativistic viscoelastic model with such parameters can be regarded as a causal completion of relativistic Navier-Stokes fluid mechanics. By adjusting parameters to various values, this theory can treat a wide variety of materials including elastic materials, Maxwell materials, Kelvin-Voigt materials, and (a nonlinearly generalized version of) simplified Israel-Stewart fluids, and thus we expect the theory to be the most universal description of single-component relativistic continuum materials. We also show that the presence of strains and the corresponding change in temperature are naturally unified through the Tolman law in a generally covariant description of continuum mechanics.
Supersymmetric Fluid Mechanics
R. Jackiw; A. P. Polychronakos
2000-07-17T23:59:59.000Z
When anticommuting Grassmann variables are introduced into a fluid dynamical model with irrotational velocity and no vorticity, the velocity acquires a nonvanishing curl and the resultant vorticity is described by Gaussian potentials formed from the Grassmann variables. Upon adding a further specific interaction with the Grassmann degrees of freedom, the model becomes supersymmetric.
Isospin splitting of nucleon effective mass and shear viscosity of nuclear matter
Jun Xu
2015-02-09T23:59:59.000Z
Based on an improved isospin- and momentum-dependent interaction, we have studied the qualitative effect of isospin splitting of nucleon effective mass on the specific shear viscosity of neutron-rich nuclear matter from a relaxation time approach. It is seen that for $m_n^\\star>m_p^\\star$, the relaxation time of neutrons is smaller and the neutron flux between flow layers is weaker, leading to a smaller specific shear viscosity of neutron-rich matter compared to the case for $m_n^\\starviscosity near nuclear liquid-gas phase transition.
Shear Viscosity of Hot QED at Finite Density from Kubo Formula
Hui Liu; Defu Hou; Jiarong Li
2006-02-24T23:59:59.000Z
Within the framework of finite temperature field theory this paper discusses the shear viscosity of hot QED plasma through Kubo formula at one-loop skeleton diagram level with a finite chemical potential. The effective widths(damping rates) are introduced to regulate the pinch singularities. The finite chemical potential, which enhances the contributions to the shear viscosity from the electrons while suppresses those from the photons, finally gives a positive contribution compared to the pure temperature environment. The result agrees with that from the kinetics theory qualitatively.
Bulk viscosity-driven freeze-out in heavy ion collisions
Giorgio Torrieri; Igor Mishustin; Boris Tomášik
2009-01-02T23:59:59.000Z
We give an review the HBT puzzle, and argue that its resolution requires the introduction of new physics close to the phase transition scale. We argue that a candidate for this new physics is bulk viscosity, recently postulated to peak, and even diverge, close to the phase transition temperature. We show that such a viscosity peak can force the system created in heavy ion collisions to become unstable, and filament into fragments whose size is weakly dependent on the global size of the system, thereby triggering freeze-out.
Cesaroni, Annalisa [Dipartimento di Matematica P. e A., Universita di Padova, via Belzoni 7, 35131 Padova (Italy)], E-mail: acesar@math.unipd.it
2006-01-15T23:59:59.000Z
We prove optimality principles for semicontinuous bounded viscosity solutions of Hamilton-Jacobi-Bellman equations. In particular, we provide a representation formula for viscosity supersolutions as value functions of suitable obstacle control problems. This result is applied to extend the Lyapunov direct method for stability to controlled Ito stochastic differential equations. We define the appropriate concept of the Lyapunov function to study stochastic open loop stabilizability in probability and local and global asymptotic stabilizability (or asymptotic controllability). Finally, we illustrate the theory with some examples.
MEASUREMENT OF INTERFACIAL TENSION IN FLUID-FLUID SYSTEMS
Loh, Watson
MEASUREMENT OF INTERFACIAL TENSION IN FLUID-FLUID SYSTEMS J. Drelich Ch. Fang C.L. White Michigan been used to measure interfacial tensions between immisci- ble fluid phases. A recent monograph sources of information on the in- terfacial tension measurement methods include selected chapters in Refs
Magnetically stimulated fluid flow patterns
Martin, Jim; Solis, Kyle
2014-03-06T23:59:59.000Z
Sandia National Laboratories' Jim Martin and Kyle Solis explain research on the effects of magnetic fields on fluid flows and how they stimulate vigorous flows. Fluid flow is a necessary phenomenon in everything from reactors to cooling engines in cars.
Magnetically stimulated fluid flow patterns
Martin, Jim; Solis, Kyle
2014-08-06T23:59:59.000Z
Sandia National Laboratories' Jim Martin and Kyle Solis explain research on the effects of magnetic fields on fluid flows and how they stimulate vigorous flows. Fluid flow is a necessary phenomenon in everything from reactors to cooling engines in cars.
Fluid Flow Modeling in Fractures
Sarkar, Sudipta
2004-01-01T23:59:59.000Z
In this paper we study fluid flow in fractures using numerical simulation and address the challenging issue of hydraulic property characterization in fractures. The methodology is based on Computational Fluid Dynamics, ...
Computer Vision in Fluid Mechanics
Aminfar, AmirHessam
2015-01-01T23:59:59.000Z
Laminar flows are usually unidirectional flows, which the fluidlaminar flows ? Streak line: Streak line is locus of fluid
Ying, D.H.S.; Sivasubramanian, R.; Moujaes, S.F.; Givens, E.N.
1982-04-01T23:59:59.000Z
A commercial coal liquefaction plant will employ vertical tubular reactors feeding slurry and gas concurrently upward through these vessels. In the SRC-I plant design the reactor is essentially an empty vessel with only a distributor plate located near the inlet. Because the commercial plant represents a considerable scale-up over Wilsonville or any pilot plant, this program addressed the need for additional data on behavior of three phase systems in large vessels. Parameters that were investigated in this program were studied at conditions that relate directly to projected plant operating conditions. The fluid dynamic behavior of the three-phase upflow system was studied by measuring gas and slurry holdup, liquid dispersion, solids suspension and solids accumulation. The dependent parameters are gas and liquid velocities, solid particle size, solids concentration, liquid viscosity, liquid surface tension and inlet distributor. Within the range of liquid superficial velocity from 0.0 to 0.5 ft/sec, gas holdup is found to be independent of liquid flow which agrees with other investigators. The results also confirm our previous finding that gas holdup is independent of column diameter when the column diameter is 5 inches or larger. The gas holdup depends strongly on gas flow rate; gas holdup increases with increasing gas velocity. The effect of solids particles on gas holdup depends on the gas flow rate. Increasing liquid viscosity and surface tension reduce gas holdup which agrees with other investigators. Because of the complexity of the system, we could not find a single correlation to best fit all the data. The degree of liquid backmixing markedly affects chemical changes occurring in the dissolver, such as sulfur removal, and oil and distillate formation.
Paul Hopkins; Matthias Schmidt
2010-07-29T23:59:59.000Z
Using a fundamental measure density functional theory we investigate both bulk and inhomogeneous systems of the binary non-additive hard sphere model. For sufficiently large (positive) non-additivity the mixture phase separates into two fluid phases with different compositions. We calculate bulk fluid-fluid coexistence curves for a range of size ratios and non-additivity parameters and find that they compare well to simulation results from the literature. Using the Ornstein-Zernike equation, we investigate the asymptotic, r->infinity, decay of the partial pair correlation functions, g_ij(r). At low densities there occurs a structural crossover in the asymptotic decay between two different damped oscillatory modes with different wavelengths corresponding to the two intra-species hard core diameters. On approaching the fluid-fluid critical point there is Fisher-Widom crossover from exponentially damped oscillatory to monotonic asymptotic decay. Using the density functional we calculate the density profiles for the planar free fluid-fluid interface between coexisting fluid phases. We show that the type of asymptotic decay of g_ij(r) not only determines the asymptotic decay of the interface profiles, but is also relevant for intermediate and even short-ranged behaviour. We also determine the surface tension of the free fluid interface, finding that it increases with non-additivity, and that on approaching the critical point mean-field scaling holds.
Mathematical thermodynamics of fluids Eduard Feireisl
KrejcĂ, Pavel
Mathematical thermodynamics of fluids Eduard Feireisl Institute of Mathematics, Academy of Sciences Agreement 320078 CIME courses, Cetraro 29 June - 4 July 2015 Eduard Feireisl Thermodynamics of fluids #12 Thermodynamics of fluids #12;Fluids at equilibrium Thermodynamic state variables mass density
Thermalization and possible quantum relaxation times in "classical" fluids: theory and experiment
Z. Nussinov; F. Nogueira; M. Blodgett; K. F. Kelton
2015-09-07T23:59:59.000Z
Quantum effects in material systems are often pronounced at low energies and become insignificant at high temperatures. We find that, perhaps counterintuitively, certain quantum effects may follow the opposite route and become sharp when extrapolated to high temperature within a "classical" liquid phase. In the current work, we suggest basic quantum bounds on relaxation (and thermalization) times, examine kinetic theory by taking into account such possible fundamental quantum time scales, find new general equalities connecting semi-classical dynamics and thermodynamics to Planck's constant, and compute current correlation functions. Our analysis suggests that, on average, the extrapolated high temperature dynamical viscosity of general liquids may tend to a value set by the product of the particle number density ${\\sf n}$ and Planck's constant $h$. We compare this theoretical result with experimental measurements of an ensemble of 23 metallic fluids where this seems to indeed be the case. The extrapolated high temperature viscosity of each of these liquids $\\eta$ divided (for each respective fluid by its value of ${\\sf n} h$) veers towards a Gaussian with an ensemble average value that is close to unity up to an error of size $0.6 \\%$. Inspired by the Eigenstate Thermalization Hypothesis, we suggest a relation between the lowest equilibration temperature to the melting or liquidus temperature and discuss a possible corollary concerning the absence of finite temperature "ideal glass" transitions. We suggest a general quantum mechanical derivation for the viscosity of glasses at general temperatures. We invoke similar ideas to discuss other transport properties and demonstrate how simple behaviors including resistivity saturation and linear $T$ resistivity may appear very naturally. Our approach suggests that minimal time lags may be present in fluid dynamics.
Fayer, Michael D.
Dynamics of Hemoglobin in Human Erythrocytes and in Solution: Influence of Viscosity Studied by Ultrafast Vibrational Echo Experiments Brian L. McClain, Ilya J. Finkelstein, and M. D. Fayer* Contribution experiments are used to measure the vibrational dephasing of the CO stretching mode of hemoglobin-CO (Hb
Bulk viscosity and the phase transition of the linear sigma model
Antonio Dobado; Juan M. Torres-Rincon
2012-10-04T23:59:59.000Z
In this work we deal with the critical behavior of the bulk viscosity in the linear sigma model (LSM) as an example of a system which can be treated by using different techniques. Starting from the Boltzmann-Uehling-Uhlenbeck equation we compute the bulk viscosity over entropy density of the LSM in the large-N limit. We search for a possible maximum of the bulk viscosity over entropy density at the critical temperature of the chiral phase transition. The information about this critical temperature, as well as the effective masses, is obtained from the effective potential. We find that the expected maximum (as a measure of the conformality loss) is absent in the large N in agreement with other models in the same limit. However, this maximum appears when, instead of the large-N limit, the Hartree approximation within the Cornwall-Jackiw-Tomboulis (CJT) formalism is used. Nevertheless, this last approach to the LSM does not give rise to the Goldstone theorem and also predicts a first order phase transition instead of the expected second order one. Therefore both, the large-N limit and the CJT-Hartree approximations, should be considered as complementary for the study of the critical behavior of the bulk viscosity in the LSM.
Shear Viscosity from AdS Born-Infeld Black Holes
Rong-Gen Cai; Ya-Wen Sun
2008-09-23T23:59:59.000Z
We calculate the shear viscosity in the frame of AdS/CFT correspondence for the field theory with a gravity dual of Einstein-Born-Infeld gravity. We find that the ratio of $\\eta/s$ is still the conjectured universal value $1/4\\pi$ at least up to the first order of the Born-Infeld parameter $1/b^2$.
Viscosity and mutual diffusion of deuterium-tritium mixtures in the warm-dense-matter regime
Kress, J. D.; Cohen, James S.; Horner, D. A.; Collins, L. A. [Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Lambert, F. [CEA, DAM, DIF, F-91297 Arpajon (France)
2010-09-15T23:59:59.000Z
We have calculated viscosity and mutual diffusion of deuterium-tritium (DT) in the warm, dense matter regime for densities from 5 to 20 g/cm{sup 3} and temperatures from 2 to 10 eV, using both finite-temperature Kohn-Sham density-functional theory molecular dynamics (QMD) and orbital-free molecular dynamics (OFMD). The OFMD simulations are in generally good agreement with the benchmark QMD results, and we conclude that the simpler OFMD method can be used with confidence in this regime. For low temperatures (3 eV and below), one-component plasma (OCP) model simulations for diffusion agree with the QMD and OFMD calculations, but deviate by 30% at 10 eV. In comparison with the QMD and OFMD results, the OCP viscosities are not as good as for diffusion, especially for 5 g/cm{sup 3} where the temperature dependence is significantly different. The QMD and OFMD reduced diffusion and viscosity coefficients are found to depend largely, though not completely, only on the Coulomb coupling parameter {Gamma}, with a minimum in the reduced viscosity at {Gamma}{approx_equal}25, approximately the same position found in the OCP simulations. The QMD and OFMD equations of state (pressure) are also compared with the hydrogen two-component plasma model.
Viscosity of carbon nanotubes water based nanofluids: Influence of1 concentration and temperature2
Paris-Sud XI, Université de
1 Viscosity of carbon nanotubes water based nanofluids: Influence of1 concentration and temperature of carbon nanotubes water-based nanofluids24 are presented considering the influence of particle volume nanofluids behave as shear-thinning materials for high particle content. For lower particle29 content
Shear history effect on the viscosity of carbon nanotubes water-based nanofluid
Paris-Sud XI, Université de
1 Shear history effect on the viscosity of carbon nanotubes water-based nanofluid Patrice Estellé results on the steady state rheological behaviour of carbon nanotube (CNT) water-based nanofluid-based nanofluid. Two types of preshear history effect are studied: the influence of stress rate during preshear
A NOTE ON FRONT TRACKING AND THE EQUIVALENCE BETWEEN VISCOSITY SOLUTIONS OF HAMILTON-JACOBI solution of the Hamilton-Jacobi equation u t + H(ux ) = 0. In our proof we work directly with the de#12 conservation laws to Hamilton-Jacobi equations and derive some of its properties. 1. Introduction It is well
Elliott, James
dispersed in polycarbonate, where they reported a step change in viscosity for 2 wt % loading of MWCNTs in polycarbonate at low shear rates. The rheological behavior of MWCNTs in polypropylene, and their corresponding conductivity. Recently, Xu et al. 2005 again reported on the systematic development of viscoelasticity
Neutrino emissivity and bulk viscosity of iso-CSL quark matter in neutron stars
David B. Blaschke; Jens Berdermann
2007-10-27T23:59:59.000Z
We present results for neutrino emissivities and bulk viscosities of a two-flavor color superconducting quark matter phase with isotropic color-spin-locked (iso-CSL) single-flavor pairing which fulfill the constraints on quark matter derived from cooling and rotational evolution of compact stars. We compare with results for the phenomenologically successful, but yet heuristic 2SC+X phase.
On the rate-independent limit of systems with dry friction and small viscosity
Mielke, Alexander
On the rate-independent limit of systems with dry friction and small viscosity Messoud A. Efendiev of this work is to present a model which is able to account for viscous as well as for dry-friction effects slow time scale, in which viscous transitions are seen as instantaneous jumps. However, effects of dry
An optimal viscosity profile in enhanced oil recovery by polymer Prabir Daripa1,
Daripa, Prabir
An optimal viscosity profile in enhanced oil recovery by polymer flooding Prabir Daripa1, and G. Pa is one of the effective methods of enhanced (tertiary) oil recovery. A classical model of this process channeling of flow through high permeable region in the heterogeneous case. Key words: enhanced oil recovery
Mantle dynamics in super-Earths: Post-perovskite rheology and self-regulation of viscosity
Tackley, Paul J.
Mantle dynamics in super-Earths: Post-perovskite rheology and self-regulation of viscosity P, Massachusetts Institute of Technology, Cambridge, MA 02139, USA a r t i c l e i n f o Article history: Received a self-regulation of deep mantle temperature. The deep mantle is not adiabatic; instead feedback between
Hole Growth as a Microrheological Probe to Measure the Viscosity of Polymers Confined to Thin Films
Dutcher, John
Hole Growth as a Microrheological Probe to Measure the Viscosity of Polymers Confined to Thin Films thin freely-standing films revealed that hole formation and growth occurs only at temperatures: 30113021, 2006 Keywords: glass transition; nanoscale confinement; rheology; thin films; viscoelastic
Experimental and Theoretical Determination of Heavy Oil Viscosity Under Reservoir Conditions
Gabitto, Jorge; Barrufet, Maria
2002-03-11T23:59:59.000Z
The main objective of this research was to propose a simple procedure to predict heavy oil viscosity at reservoir conditions as a function of easily determined physical properties. This procedure will avoid costly experimental testing and reduce uncertainty in designing thermal recovery processes.
An optimal viscosity profile in enhanced oil recovery by polymer flooding
Daripa, Prabir
An optimal viscosity profile in enhanced oil recovery by polymer flooding Prabir Daripa a,*, G; accepted 3 July 2004 (Communicated by L. DEBNATH) Abstract Forced displacement of oil by polymer flooding reserved. Keywords: Enhanced oil recovery; Polymer flooding; Linear stability 0020-7225/$ - see front
Peltier, W.R.; Jiang, X. [Univ. of Toronto, Ontario (Canada)] [Univ. of Toronto, Ontario (Canada)
1996-02-10T23:59:59.000Z
This report explores the use of the present-day rate and direction of polar wander and the magnitude of the nontidal acceleration of the rate of planetary rotation of the earth to contrain the viscosity of the lower regions of the lower mantle.
Acoustic concentration of particles in fluid flow
Ward, Michael D. (Los Alamos, NM); Kaduchak, Gregory (Los Alamos, NM)
2010-11-23T23:59:59.000Z
An apparatus for acoustic concentration of particles in a fluid flow includes a substantially acoustically transparent membrane and a vibration generator that define a fluid flow path therebetween. The fluid flow path is in fluid communication with a fluid source and a fluid outlet and the vibration generator is disposed adjacent the fluid flow path and is capable of producing an acoustic field in the fluid flow path. The acoustic field produces at least one pressure minima in the fluid flow path at a predetermined location within the fluid flow path and forces predetermined particles in the fluid flow path to the at least one pressure minima.
Oscillating fluid power generator
Morris, David C
2014-02-25T23:59:59.000Z
A system and method for harvesting the kinetic energy of a fluid flow for power generation with a vertically oriented, aerodynamic wing structure comprising one or more airfoil elements pivotably attached to a mast. When activated by the moving fluid stream, the wing structure oscillates back and forth, generating lift first in one direction then in the opposite direction. This oscillating movement is converted to unidirectional rotational movement in order to provide motive power to an electricity generator. Unlike other oscillating devices, this device is designed to harvest the maximum aerodynamic lift forces available for a given oscillation cycle. Because the system is not subjected to the same intense forces and stresses as turbine systems, it can be constructed less expensively, reducing the cost of electricity generation. The system can be grouped in more compact clusters, be less evident in the landscape, and present reduced risk to avian species.
Galilean relativistic fluid mechanics
Ván, Péter
2015-01-01T23:59:59.000Z
Single component Galilean-relativistic (nonrelativistic) fluids are treated independently of reference frames. The basic fields are given, their balances, thermodynamic relations and the entropy production is calculated. The usual relative basic fields, the mass, momentum and energy densities, the diffusion current density, the pressure tensor and the heat flux are the time- and spacelike components of the third order mass-momentum-energy density tensor according to a velocity field. The transformation rules of the basic fields are derived and prove that the non-equilibrium thermodynamic background theory, that is the Gibbs relation, extensivity condition and the entropy production is absolute, that is independent of the reference frame and also of the fluid velocity. --- Az egykomponensu Galilei-relativisztikus (azaz nemrelativisztikus) disszipativ folyadekokat vonatkoztatasi rendszertol fuggetlenul targyaljuk. Megadjuk az alapmennyisegeket, ezek merlegeit, a termodinamikai osszefuggeseket es kiszamoljuk az ...
Fluid bed material transfer method
Pinske, Jr., Edward E. (Akron, OH)
1994-01-01T23:59:59.000Z
A fluidized bed apparatus comprising a pair of separated fluid bed enclosures, each enclosing a fluid bed carried on an air distributor plate supplied with fluidizing air from below the plate. At least one equalizing duct extending through sidewalls of both fluid bed enclosures and flexibly engaged therewith to communicate the fluid beds with each other. The equalizing duct being surrounded by insulation which is in turn encased by an outer duct having expansion means and being fixed between the sidewalls of the fluid bed enclosures.
Downhole Fluid Analyzer Development
Bill Turner
2006-11-28T23:59:59.000Z
A novel fiber optic downhole fluid analyzer has been developed for operation in production wells. This device will allow real-time determination of the oil, gas and water fractions of fluids from different zones in a multizone or multilateral completion environment. The device uses near infrared spectroscopy and induced fluorescence measurement to unambiguously determine the oil, water and gas concentrations at all but the highest water cuts. The only downhole components of the system are the fiber optic cable and windows. All of the active components--light sources, sensors, detection electronics and software--will be located at the surface, and will be able to operate multiple downhole probes. Laboratory testing has demonstrated that the sensor can accurately determine oil, water and gas fractions with a less than 5 percent standard error. Once installed in an intelligent completion, this sensor will give the operating company timely information about the fluids arising from various zones or multilaterals in a complex completion pattern, allowing informed decisions to be made on controlling production. The research and development tasks are discussed along with a market analysis.
Parametric study to evaluate benefits of fracture fluid quality control and in-situ stress research
Satayapunt, Jeeradete
1991-01-01T23:59:59.000Z
? EFFECTS OF FRACTURE FLUID VISCOSITY AND APPENDIX A ? GRAPHS AND EQUATIONS OF DISCOUNTED ULTIMATE IN-SITU STRESS CONTRAST ON PROPPED FRACTURE LENGTH AND REVENUE FOR THE SIX TIGHT GAS FORMATIONS . 80 APPENDIX C ? BENEFITS OF PERFORMING FRACTURE... analysis from step-rate test 15 2. 8 Schematic of the Farm Model 50C 2. 9 Flow schematic of GRI rheology unit. 19 3. 1 Discounted ultimate gas recovery vs. propped fracture length for the six formations . 24 3. 2 Variable cost vs. propped fracture...
Tiainen, Ari Lauri
1986-01-01T23:59:59.000Z
stress is defined as force per unit area, and is distributed continuously throughout any continuous medium which is subjected to external i'oroes. Viscosity is a rheological property of a material sud is defined. as the ratio of shear stress to shear... of Rheologics1 Characteristics of Cross-Linked ~ing Fluids Using s pipe Visccmetm. (Deoanber 1986) Ari Lsuri ~, B. S. , Pari. 's Technical University Chairman of Advisory Committee: Dr, S. A. Eolditch In low perme~ty re~s the usual need for long hydraulic...
Sawan, Samuel P. (Tyngsborough, MA); Talhi, Abdelhafid (Rochester, MI); Taylor, Craig M. (Jemez Springs, NM)
1998-08-25T23:59:59.000Z
The invention features polymers with increased order, and methods of making them featuring a dense gas.
Null Fluids - A New Viewpoint of Galilean Fluids
Banerjee, Nabamita; Jain, Akash
2015-01-01T23:59:59.000Z
This article is a detailed version of our short letter `On equilibrium partition function for non-relativistic fluid' [arXiv:1505.05677] extended to include an anomalous $U(1)$ symmetry. We construct a relativistic system, which we call null fluid and show that it is in one-to-one correspondence with a Galilean fluid living in one lower dimension. The correspondence is based on light cone reduction, which is known to reduce the Poincare symmetry of a theory to Galilean in one lower dimension. We show that the proposed null fluid and the corresponding Galilean fluid have exactly same symmetries, thermodynamics, constitutive relations, and equilibrium partition to all orders in derivative expansion. We also devise a mechanism to introduce $U(1)$ anomaly in even dimensional Galilean theories using light cone reduction, and study its effect on the constitutive relations of a Galilean Fluid.
Null Fluids - A New Viewpoint of Galilean Fluids
Nabamita Banerjee; Suvankar Dutta; Akash Jain
2015-09-15T23:59:59.000Z
This article is a detailed version of our short letter `On equilibrium partition function for non-relativistic fluid' [arXiv:1505.05677] extended to include an anomalous $U(1)$ symmetry. We construct a relativistic system, which we call null fluid and show that it is in one-to-one correspondence with a Galilean fluid living in one lower dimension. The correspondence is based on light cone reduction, which is known to reduce the Poincare symmetry of a theory to Galilean in one lower dimension. We show that the proposed null fluid and the corresponding Galilean fluid have exactly same symmetries, thermodynamics, constitutive relations, and equilibrium partition to all orders in derivative expansion. We also devise a mechanism to introduce $U(1)$ anomaly in even dimensional Galilean theories using light cone reduction, and study its effect on the constitutive relations of a Galilean Fluid.
M. Bahrami Fluid Mechanics (S 09) Fluid statics 9 Archimedes's 1st
Bahrami, Majid
M. Bahrami Fluid Mechanics (S 09) Fluid statics 9 Buoyancy Archimedes's 1st laws #12; M. Bahrami Fluid Mechanics (S 09) Fluid statics 10 Fig. 11: Archimedes second law. Bahrami Fluid Mechanics (S 09) Fluid statics 11 Pressure distribution in rigidbody motion Fluids
Shirish Patil; Abhijit Dandekar; Mary Beth Leigh
2008-12-31T23:59:59.000Z
A large proportion of Alaska North Slope (ANS) oil exists in the form of viscous deposits, which cannot be produced entirely using conventional methods. Microbially enhanced oil recovery (MEOR) is a promising approach for improving oil recovery for viscous deposits. MEOR can be achieved using either ex situ approaches such as flooding with microbial biosurfactants or injection of exogenous surfactant-producing microbes into the reservoir, or by in situ approaches such as biostimulation of indigenous surfactant-producing microbes in the oil. Experimental work was performed to analyze the potential application of MEOR to the ANS oil fields through both ex situ and in situ approaches. A microbial formulation containing a known biosurfactant-producing strain of Bacillus licheniformis was developed in order to simulate MEOR. Coreflooding experiments were performed to simulate MEOR and quantify the incremental oil recovery. Properties like viscosity, density, and chemical composition of oil were monitored to propose a mechanism for oil recovery. The microbial formulation significantly increased incremental oil recovery, and molecular biological analyses indicated that the strain survived during the shut-in period. The indigenous microflora of ANS heavy oils was investigated to characterize the microbial communities and test for surfactant producers that are potentially useful for biostimulation. Bacteria that reduce the surface tension of aqueous media were isolated from one of the five ANS oils (Milne Point) and from rock oiled by the Exxon Valdez oil spill (EVOS), and may prove valuable for ex situ MEOR strategies. The total bacterial community composition of the six different oils was evaluated using molecular genetic tools, which revealed that each oil tested possessed a unique fingerprint indicating a diverse bacterial community and varied assemblages. Collectively we have demonstrated that there is potential for in situ and ex situ MEOR of ANS oils. Future work should focus on lab and field-scale testing of ex situ MEOR using Bacillus licheniformis as well as the biosurfactant-producing strains we have newly isolated from the Milne Point reservoir and the EVOS environment.
Boyer, Edmond
L-535 Viscosity calculation of polydisperse branching polymers near gel point D. Sievers Institut Whitney. Abstract. 2014 The viscosity of randomly branched polymers has been calculated based that the first choice is better direct near the gel point and yields a logarithmic divergence of the viscosity
Heat recirculating cooler for fluid stream pollutant removal
Richards, George A. (Morgantown, WV); Berry, David A. (Morgantown, WV)
2008-10-28T23:59:59.000Z
A process by which heat is removed from a reactant fluid to reach the operating temperature of a known pollutant removal method and said heat is recirculated to raise the temperature of the product fluid. The process can be utilized whenever an intermediate step reaction requires a lower reaction temperature than the prior and next steps. The benefits of a heat-recirculating cooler include the ability to use known pollutant removal methods and increased thermal efficiency of the system.
Modeling and Algorithmic Approaches to Constitutively-Complex, Micro-structured Fluids
Forest, Mark Gregory [University of North Carolina at Chapel Hill] [University of North Carolina at Chapel Hill
2014-05-06T23:59:59.000Z
The team for this Project made significant progress on modeling and algorithmic approaches to hydrodynamics of fluids with complex microstructure. Our advances are broken down into modeling and algorithmic approaches. In experiments a driven magnetic bead in a complex fluid accelerates out of the Stokes regime and settles into another apparent linear response regime. The modeling explains the take-off as a deformation of entanglements, and the longtime behavior is a nonlinear, far-from-equilibrium property. Furthermore, the model has predictive value, as we can tune microstructural properties relative to the magnetic force applied to the bead to exhibit all possible behaviors. Wave-theoretic probes of complex fluids have been extended in two significant directions, to small volumes and the nonlinear regime. Heterogeneous stress and strain features that lie beyond experimental capability were studied. It was shown that nonlinear penetration of boundary stress in confined viscoelastic fluids is not monotone, indicating the possibility of interlacing layers of linear and nonlinear behavior, and thus layers of variable viscosity. Models, algorithms, and codes were developed and simulations performed leading to phase diagrams of nanorod dispersion hydrodynamics in parallel shear cells and confined cavities representative of film and membrane processing conditions. Hydrodynamic codes for polymeric fluids are extended to include coupling between microscopic and macroscopic models, and to the strongly nonlinear regime.
The effect of lymphatic fluid protein concentration on lymphatic resistance
Walker, Ellen Marie
2013-02-22T23:59:59.000Z
. The factors affecting lymph flow (Qc) have been modeled on Ohm's Law: Qc=(P+PpP)/Rc where P, is inflow pressure, P~ is pump pressure, P? is outflow pressure, and R~ is lymphatic resistance (Drake 1987). A common cause of edema formation is increased.... Allen BV, and Blackmore D J. Relationship between paired plasma and serum viscosity and plasma proteins in the horse. Research in Veterinary Science 36: 360-363, 1984. 2, Drake RE, Laine GA, Allen SJ, Katz J, and Gabel JC. AModelofthe Lung...
Ultrasonic fluid quality sensor system
Gomm, Tyler J. (Meridian, ID); Kraft, Nancy C. (Idaho Falls, ID); Phelps, Larry D. (Pocatello, ID); Taylor, Steven C. (Idaho Falls, ID)
2002-10-08T23:59:59.000Z
A system for determining the composition of a multiple-component fluid and for determining linear flow comprising at least one sing-around circuit that determines the velocity of a signal in the multiple-component fluid and that is correlatable to a database for the multiple-component fluid. A system for determining flow uses two of the inventive circuits, one of which is set at an angle that is not perpendicular to the direction of flow.
Ultrasonic Fluid Quality Sensor System
Gomm, Tyler J. (Meridian, ID); Kraft, Nancy C. (Idaho Falls, ID); Phelps, Larry D. (Pocatello, ID); Taylor, Steven C. (Idaho Falls, ID)
2003-10-21T23:59:59.000Z
A system for determining the composition of a multiple-component fluid and for determining linear flow comprising at least one sing-around circuit that determines the velocity of a signal in the multiple-component fluid and that is correlatable to a database for the multiple-component fluid. A system for determining flow uses two of the inventive circuits, one of which is set at an angle that is not perpendicular to the direction of flow.
A. S. Khvorostukhin; V. D. Toneev; D. N. Voskresensky
2009-12-18T23:59:59.000Z
The shear ($\\eta$) and bulk ($\\zeta$) viscosities are calculated in a quasiparticle relaxation time approximation for a hadron matter described within the relativistic mean-field based model with scaled hadron masses and couplings. Comparison with results of other models is presented. We demonstrate that a small value of the shear viscosity to entropy density ratio required for explaining a large elliptic flow observed at RHIC may be reached in the hadron phase. Large values of the bulk viscosity are noted in case of the baryon enriched matter.
Viscosity control of the dynamic self-assembly in ferromagnetic suspensions
D. L. Piet; A. V. Straube; A. Snezhko; I. S. Aranson
2013-04-17T23:59:59.000Z
Recent studies of dynamic self-assembly in ferromagnetic colloids suspended in liquid-air or liquid-liquid interfaces revealed a rich variety of dynamic structures ranging from linear snakes to axisymmetric asters, which exhibit novel morphology of the magnetic ordering accompanied by large-scale hydrodynamic flows. Based on controlled experiments and first principle theory, we argue that the transition from snakes to asters is governed by the viscosity of the suspending liquid where less viscous liquids favor snakes and more viscous, asters. By obtaining analytic solutions of the time-averaged Navier-Stokes equations, we gain insights into the role of mean hydrodynamic flows and an overall balance of forces governing the self-assembly. Our results illustrate that the viscosity can be used to control the outcome of the dynamic self-assembly in magnetic colloidal suspensions.
Viscosity method for Homogenization of Parabolic Nonlinear Equations in Perforated Domains
Kim, Sunghoon
2011-01-01T23:59:59.000Z
In this paper, we develop a viscosity method for Homogenization of Nonlinear Parabolic Equations constrained by highly oscillating obstacles or Dirichlet data in perforated domains. The Dirichlet data on the perforated domain can be considered as a constraint or an obstacle. Homogenization of nonlinear eigen value problems has been also considered to control the degeneracy of the Porous medium equation in perforated domains. For the simplicity, we consider obstacles that consist of cylindrical columns distributed periodically and perforated domains with punctured balls. If the decay rate of the capac- ity of columns or the capacity of punctured ball is too high or too small, the limit of u\\k{o} will converge to trivial solutions. The critical decay rates of having nontrivial solution are obtained with the construction of barriers. We also show the limit of u\\k{o} satisfies a homogenized equation with a term showing the effect of the highly oscillating obstacles or perforated domain in viscosity sense.
Shear Viscosity and Phase Diagram from Polyakov$-$Nambu$-$Jona-Lasinio model
Sanjay K. Ghosh; Sibaji Raha; Rajarshi Ray; Kinkar Saha; Sudipa Upadhaya
2014-11-12T23:59:59.000Z
We discuss a detailed study of the variation of shear viscosity, $\\eta$, with temperature and baryon chemical potential within the framework of Polyakov$-$Nambu$-$Jona-Lasinio model. $\\eta$ is found to depend strongly on the spectral width of the quasi-particles present in the model. The variation of $\\eta$ across the phase diagram has distinctive features for different kinds of transitions. These variations have been used to study the possible location of the Critical End Point (CEP), and cross-checked with similar studies of variation of specific heat. Finally using a parameterization of freeze-out surface in heavy-ion collision experiments, the variation of shear viscosity to entropy ratio has also been discussed as a function of the center of mass energy of collisions.
Inhomogeneous Dark Fluid and Dark Matter, Leading to a Bounce Cosmology
Brevik, Iver
2015-01-01T23:59:59.000Z
The purpose of this short review is to describe cosmological models with a linear inhomogeneous time-dependent equation of state (EoS) for the dark energy, when the dark fluid is coupled with dark matter. This may lead to a bounce cosmology. We consider equivalent descriptions in terms of the EoS parameters for an exponential, a power-law, or a double-exponential law for the scale factor $a$. Stability issues are discussed by considering small perturbations around the critical points for the bounce, in the early as well as in the late, universe. The latter part of the paper is concerned with dark energy coupled with dark matter in viscous fluid cosmology. We allow the bulk viscosity $\\zeta=\\zeta(H,t)$ to be a function of the Hubble parameter and the time, and consider the Little Rip, the Pseudo Rip, and the bounce universe. Analytic expressions for characteristic properties of these cosmological models are obtained.
Shear viscosity of pure Yang-Mills theory at strong coupling
Antal Jakovac; Daniel Nogradi
2008-12-05T23:59:59.000Z
We calculate the shear viscosity to entropy density ratio in pure SU(N) Yang-Mills theory below the critical temperature using the strong coupling expansion. The result for the eta/s ratio for temperatures around the phase transition is 0.22 for N = 2 and 0.028N^2 for N > 2. The results are consistent with the conjectured 1/4pi lower bound inspired by the AdS/CFT correspondence.
Viscosity of plant oils as a function of temperature, fatty acid chain length, and unsaturation
Neo, Tong Heng
1988-01-01T23:59:59.000Z
VISCOS1TY OF PLANT OILS AS A FUNCTION OF TEMPERATURE, FATIY ACID CHAIN LENGTH, AND UNSATURATION A Thesis by TONG HENG NEO 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 1988 Major Subject: Agricultural Engineering VISCOSITY OF PLANT OILS AS A FUNCTION OF TEMPERATURE, FATTY ACID CHAIN LENGTH, AND UNSATURATION A Thesis by TONG HENG NEO Approved as to style and content by...
Gandhi, Poduru Mohandas Karamchand
1966-01-01T23:59:59.000Z
Raages for Cannonading Vacuum Capillary Viscometers Viscosities at 140 F and 275 F Using Capillary V iscaaetar Rxpaasion of Triaxial Cell Mith Time At Various pressures 10 Typical Triaxial Test Data 11 Typical Triaxial Test Data 12 Typical... and the top loading cap was placed in position. 2. The circumferential surfaces of base plate and loading cap mre covered with high vacuum silicone grease. 3, The rubber membrane suitable for four inch diameter samples was placed over the speciamn using a...
Etele Molnar
2009-02-15T23:59:59.000Z
Focusing on the numerical aspects and accuracy we study a class of bulk viscosity driven expansion scenarios using the relativistic Navier-Stokes and truncated Israel-Stewart form of the equations of relativistic dissipative fluids in 1+1 dimensions. The numerical calculations of conservation and transport equations are performed using the numerical framework of flux corrected transport. We show that the results of the Israel-Stewart causal fluid dynamics are numerically much more stable and smoother than the results of the standard relativistic Navier-Stokes equations.
Fluid system for controlling fluid losses during hydrocarbon recovery operations
Johnson, M.H.; Smejkal, K.D.
1993-07-20T23:59:59.000Z
A fluid system is described for controlling fluid losses during hydrocarbon recovery operations, comprising: water; a distribution of graded calcium carbonate particle sizes; and at least one modified lignosulfonate, which is a lignosulfonate modified by polymerizing it at least to an extent effective to reduce its water solubility.
Sharadwata Pan; D. Ahirwal; Duc At Nguyen; T. Sridhar; P. Sunthar; J. Ravi Prakash
2014-10-14T23:59:59.000Z
The swelling of the viscosity radius, $\\alpha_\\eta$, and the universal viscosity ratio, $U_{\\eta R}$, have been determined experimentally for linear DNA molecules in dilute solutions with excess salt, and numerically by Brownian dynamics simulations, as a function of the solvent quality. In the latter instance, asymptotic parameter free predictions have been obtained by extrapolating simulation data for finite chains to the long chain limit. Experiments and simulations show a universal crossover for $\\alpha_\\eta$ and $U_{\\eta R}$ from $\\theta$ to good solvents in line with earlier observations on synthetic polymer-solvent systems. The significant difference between the swelling of the dynamic viscosity radius from the observed swelling of the static radius of gyration, is shown to arise from the presence of hydrodynamic interactions in the non-draining limit. Simulated values of $\\alpha_\\eta$ and $U_{\\eta R}$ are in good agreement with experimental measurements in synthetic polymer solutions reported previously, and with the measurements in linear DNA solutions reported here.
Real viscosity effects in inertial confinement fusion target deuterium–tritium micro-implosions
Mason, R. J., E-mail: rodmason01@msn.com; Kirkpatrick, R. C.; Faehl, R. J. [Research Applications Corporation, Los Alamos, New Mexico 87544 (United States)] [Research Applications Corporation, Los Alamos, New Mexico 87544 (United States)
2014-02-15T23:59:59.000Z
We report on numerical studies of real viscous effects on the implosion characteristics of imploded DT micro-targets. We use the implicit ePLAS code to perform 2D simulations of spherical and slightly ellipsoidal DT shells on DT gas filled ?40??m diameter voids. Before their final implosions the shells have been nearly adiabatically compressed up to 10{sup 2} or 10{sup 3}?g/cm{sup 3} densities. While the use of conventional artificial viscosity can lead to high central densities for initially spherical shells, we find that a real physical viscosity from ion-ion collisions can give a high (>20?keV) central temperature but severely reduced central density (<200?g/cm{sup 3}), while the elliptical shells evidence p?=?2 distortion of the heated central fuel region. These results suggest that the general use of artificial viscosities in Inertial Confinement Fusion (ICF) modeling may have lead to overly optimistic yields for current NIF targets and that polar direct drive with more energy for the imploding capsule may be needed for ultimate ICF success.
Chakrabarti, Brato
2015-01-01T23:59:59.000Z
This work explores a simple model of a slender, flexible structure in a uniform flow, providing analytical solutions for the translating, axially flowing equilibria of strings subjected to a uniform body force and drag forces linear in the velocities. The classical catenaries are extended to a five-parameter family of curves. A sixth parameter affects the tension in the curves. Generic configurations are planar, represented by a single first order equation for the tangential angle. The effects of varying parameters on representative shapes, orbits in angle-curvature space, and stress distributions are shown. As limiting cases, the solutions include configurations corresponding to "lariat chains" and the towing, reeling, and sedimentation of flexible cables in a highly viscous fluid. Regions of parameter space corresponding to infinitely long, semi-infinite, and finite length curves are delineated. Almost all curves subtend an angle less than $\\pi$ radians, but curious special cases with doubled or infinite ra...
Encapsulated Nanoparticle Synthesis and Characterization for Improved Storage Fluids: Preprint
Glatzmaier, G. C.; Pradhan, S.; Kang, J.; Curtis, C.; Blake, D.
2010-10-01T23:59:59.000Z
Nanoparticles are typically composed of 50--500 atoms and exhibit properties that are significantly different from the properties of larger, macroscale particles that have the same composition. The addition of these particles to traditional fluids may improve the fluids' thermophysical properties. As an example, the addition of a nanoparticle or set of nanoparticles to a storage fluid may double its heat capacity. This increase in heat capacity would allow a sensible thermal energy storage system to store the same amount of thermal energy in half the amount of storage fluid. The benefit is lower costs for the storage fluid and the storage tanks, resulting in lower-cost electricity. The goal of this long-term research is to create a new class of fluids that enable concentrating solar power plants to operate with greater efficiency and lower electricity costs. Initial research on this topic developed molecular dynamic models that predicted the energy states and transition temperatures for these particles. Recent research has extended the modeling work, along with initiating the synthesis and characterization of bare metal nanoparticles and metal nanoparticles that are encapsulated with inert silica coatings. These particles possess properties that make them excellent candidates for enhancing the heat capacity of storage fluids.