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Accelerated simulation of a heavy particle in a gas of elastic spheres. (English) Zbl 1254.74044

Summary: A new, accelerated algorithm for a system of elastic hard spheres in which one of the particles (a colloid) is significantly heavier than the others is presented. The algorithm follows the framework of the stochastic heterogeneous multiscale method. In the limit in which the ratio between the light and the heavy particles approaches zero, the dynamics of the colloid is given by a stochastic differential equation whose drift and diffusion coefficients are not known explicitly. It is shown that these coefficients can be calculated on the fly using short-time event-driven simulations, thereby allowing us to simulate the stochastic differential equation for the colloid. The efficiency of the resulting scheme is independent of the mass ratio. A few numerical examples, which serve as a proof of principle, are presented. The examples demonstrate that our results are consistent with analytical predictions in the ideal gas limit. A result of a simulation with a dense gas is also presented.

MSC:

74F20 Mixture effects in solid mechanics
82C40 Kinetic theory of gases in time-dependent statistical mechanics
37M05 Simulation of dynamical systems
65C20 Probabilistic models, generic numerical methods in probability and statistics
70K70 Systems with slow and fast motions for nonlinear problems in mechanics
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