Micro-meso coupling for hydrodynamic simulations

Abstract

We present a particle-continuum coupling for simulations in the laminar and turbulent flow regimes. The two-way coupling in the hybrid model is achieved via a direct Simulation Monte Carlo layer near walls and a Lattice-Boltzmann RD3Q41 model in the bulk. The lifting of macroscopic to microscopic dynamics is done via a novel projection scheme based on the idea of quasi-equilibrium manifold incorporating stress and heat flux as fields. The coupled solver is validated by performing simulations on the canonical plane Poiseuille and Couette flows. Turbulent flow simulation performed using minimal compute resources shows the ability of the solver to predict the regeneration cycles of coherent structures. This hybrid coupling represents a novel method for accurate description of flow physics in various hydrodynamic regimes, where stand-alone solvers fall short due to high computational expense like in DSMC or due to lack of high Knudsen flow physics in LB.