Simplified modelling of a thermal bath, with application to a fluid vortex system

Dubinkina, Svetlana;Frank, Jason;Leimkuhler, Ben
(2010) Multiscale Modeling & Simulation: a S I A M Interdisciplinary Journal — Vol. 8, n° 5, p. 1882-1901 (2010)

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Authors
  • Dubinkina, SvetlanaUCLouvain
    Author
  • Frank, JasonCWI, the Netherlands
    Author
  • Leimkuhler, BenThe University of Edinburgh, Scotland
    Author
Abstract
Based on the thermodynamic concept of a reservoir, we investigate a computational model for interaction with unresolved degrees of freedom (a thermal bath). We assume that a finite restricted system can be modelled by a generalized canonical ensemble, described by a density which is a smooth function of the energy of the restricted system. A thermostat is constructed to continuously perturb the resolved dynamics, while leaving the desired equilibrium distribution invariant. We build on a thermostatting framework developed and tested in the setting of molecular dynamics, using stochastic perturbations to control (and stabilize) the invariant measure. We also apply these techniques in the setting of a simplified point vortex flow on a disc, in which a modified Gibbs distribution (modelling a finite, rather than infinite, bath of weak vortices) provides a regularizing formulation for restricted system dynamics. Numerical experiments, effectively replacing many vortices by a few artificial degrees of freedom, are in excellent agreement with the two-scale simulations of Bühler. © 2010 Society for Industrial and Applied Mathematics.
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Citations

Dubinkina, S., Frank, J., & Leimkuhler, B. (2010). Simplified modelling of a thermal bath, with application to a fluid vortex system. Multiscale Modeling & Simulation: a S I A M Interdisciplinary Journal, 8(5), 1882-1901. https://doi.org/10.1137/100795152 (Original work published 2010)