Development and Validation of an in-House Direct Simulation Monte Carlo Code for Supersonic Rarefied Gas Microflows

Abstract An in-house Direct Simulation Monte Carlo (DSMC) code has been developed using an object-oriented interface for the purpose of eventually modelling gas and plasma microflows in micromechanical systems, by coupling it with an existing Particle-In-Cell (PIC) solver. The code is validated with canonical flow problems such as the micro-Couette and micro-Poiseuille flows. Since the emphasis is on supersonic and highly compressible flows, we perform validation studies of our algorithm for high velocity and Mach number cases, as compared to known analytical or semi-analytical profiles via asymptotic Bhatnagar-Gross-Krook (BGK) and Chapman-Enskog theory. Reasonably good agreement is found for all the test cases, which indicates the reliability of the present algorithm for modelling supersonic rarefied gas flows. Our results have implications for future validation studies of DSMC codes, where concrete quantitative theoretical and experimental comparisons across different flow configurations are required.