75 / 2019-09-29 21:47:33

A novel rigorous DSMC moving boundary algorithm for unsteady rarefied gas flows

DSMC,Unsteady,Rarefied gas,Moving boundary

The boundary decouple method is a straightforward way for solving moving boundary problems in DSMC, in which molecules are reflected approximately from the wall at the wall's old position. However, the approximation of the collision contact point between molecule and wall will bring some computational errors. In this work, we analytically evaluated the computational errors of the boundary decouple method and found that these errors become unnegligible when the normal velocity of the wall is high. Now a novel and easy-to-implement moving boundary algorithm is presented. In this methodology, molecules are reflected rigorously from the moving wall and the computational errors of boundary decouple method can be removed. Then, this methodology is applied for a series of unsteady rarefied gas flow problems, and the present results show well agreement with analytical solutions and conclusions given in classical papers.