GALCIT Colloquium
With massively parallel computers, molecular methods can be used to investigate hydrodynamic instabilities like Richtmyer-Meshkov and Rayleigh-Taylor in gases. The Direct Simulation Monte Carlo (DSMC) method is the predominant method for molecular gas dynamics. DSMC represents a gas flow using computational molecules that move, reflect, and collide stochastically with the assumption of molecular chaos. Theoretically and computationally, DSMC has been demonstrated to provide accurate solutions to the Boltzmann equation. Historically, DSMC has been highly successful simulating rarefied, high-speed flows typical of aerospace engineering. Since the molecular method in DSMC captures non-equilibrium and non-continuum transport effects and small-scale fluctuations, DSMC yields more accurate solutions over significantly wider ranges of scales and flow regimes than the more familiar Navier-Stokes equations. This talk will address the fundamental theory of DSMC, review some successful applications (Columbia accident, Mars Reconnaissance Orbiter), and demonstrate its potential for simulating hydrodynamic instabilities (Richtmyer-Meshkov, Rayleigh-Taylor) in gases using massively parallel computers.