Abstract
One of the classical questions of non-equilibrium thermodynamics is the validity of various closure approximations in nontrivial flows. We study this question for a lid-driven cavity flow using a minimal molecular model derived from the Boltzmann equation. In this nontrivial flow, we quantify the model as a superset of the Grad moment approximation and visualize the quality of the Chapman-Enskog and Grad closure approximations. It is found that the Grad closure approximation is strikingly more robust than the Chapman-Enskog approximation at all Knudsen numbers studied. Grad's approximation is used to formulate a novel outflow boundary condition for lattice Boltzmann simulations.
Original language | English (US) |
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Title of host publication | Model Reduction and Coarse-Graining Approaches for Multiscale Phenomena |
Publisher | Springer Berlin Heidelberg |
Pages | 403-422 |
Number of pages | 20 |
ISBN (Print) | 3540358854, 9783540358855 |
DOIs | |
State | Published - Dec 1 2006 |
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)