Boundary Condition at Infinity for DSMC Method

Micro Electro Mechanical Systems (MEMS) are rapidly developed, and MEMS applications are continuously growing. The Direct Simulation Monte Carlo (DSMC) approach is a basic method for studying rarefied gas flows in MEMS. Boundary conditions are an important part of DSMC simulation. Here we presented reservoir-type boundary conditions. As a test case, we used flow past flat plate normal to the inlet steam flow at Mach number 0.4 and Knudsen 0.014. The boundary cells of the computational domain were used as reservoirs to generate particles in them. Generated particles have Maxwellian velocity distribution and properties partly obtained from solution. DSMC solution was compared with the continuum model based on Navier-Stokes-Fourier equations. The comparison shows excellent agreement between DSMC and the continuum model.