Influence of the particle collision model on the results of heat flow calculations in a rarefied gas by the Direct Simulation Monte Carlo method

The Direct Simulation Monte Carlo (DSMC) method is widely used to solve problems of rarefied gas dynamics. The choice of the model of particle collisions with each other in implementation of the DSMC algorithm significantly affects the accuracy of simulations and the complexity of computations. One of the most popular particle collision models is the Variable Soft Sphere (VSS) model. In the present study, we simulate a flow arising when a heated wire is placed into a quiescent gas atmosphere (helium or argon). It is shown that the use of the VSS model with parameters based on viscosity and diffusion can lead to errors in estimating the heat flux from the wire to the ambient gas.