Hamburg 2001 – wissenschaftliches Programm
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DY: Dynamik und Statistische Physik
DY 13: Statistische Physik (Allgemein) II
DY 13.9: Vortrag
Montag, 26. März 2001, 12:30–12:45, S 7
Stochastic rotation dynamics: A Galilean-invariant mesoscopic model for fluid flow — •Thomas Ihle1,2 and Daniel M. Kroll2 — 1Institut für Computeranwendungen, ICA1, Universität Stuttgart, Pfaffenwaldring 27, 70569 Stuttgart. — 2Supercomputing Institute, University of Minnesota, 1200 Washington Ave. South, Minneapolis, MN 55415, USA.
Hydrodynamic simulations of complex liquids such as amphiphilic mixtures and polymeric liquids remain a major challenge. For these fluids, mesoscopic simulation methods are often more robust and efficient than conventional computational fluid algorithms. We present a detailed numerical and analytical study of a recently introduced stochastic model for fluid dynamics with continuous velocities and efficient multiparticle collisions [1,2]. Although a lattice is needed to define the collisions, it is shown how full Galilean-invariance can be achieved for arbitrary Mach and Schmidt numbers. The dynamics consists of streaming and collision of fluid-particles. The collision step is modeled by a stochastic rotation of the velocity of the participating particles. Analytic expressions for the viscosity and diffusion constant are derived by means of basic kinetic theory and Green-Kubo relations and compared with simulation results. Long-time tails in the velocity and stress autocorrelation functions are measured. The method is extended to incorporate a non-ideal equation of state at constant temperature, which allows the simulation of two-phase systems.
[1] A. Malevanets and R. Kapral, J. Chem. Phys. 112, 7269 (2000). [2] T. Ihle and D.M. Kroll, to appear in Phys. Rev. E, Feb. 2001.