Gas-Surface Interaction Model Evaluation for DSMC Applications

The general gas‐surface interaction event is considered to be parameterized by the molecule’s incident energy magnitude and incident angle relative to the surface normal. These parameters are used to estimate the degree of nonequilibrium that arises for typical applications, and the quality of scattering predictions made by common few‐parameter models such as the Maxwell model. Experimental measurements and molecular dynamics simulations are evaluated as potential sources of data to develop or test improved models. An ad hoc model is used to quantify the effect that improved physical realism of nonequilibrium scattering events may have on typical surface quantities of interest for a realistic application in the rarefied regime. The model allows incremental or piecemeal incorporation of scattering data as they become available.