Kinetic Methods for Solving Unsteady Problems with Jet Flows

The article presents a comparison of numerical solutions obtained by the model equations (S-model and ES-model) and the complete Boltzmann equation for the unsteady problem of gas flow in a lowpressure tank after reflection from the wall. The weak influence of the collision operator on the solution in the rarefied domain and the need to use a detailed velocity grid due to the presence of the "ray effect" are shown on the basis of numerical analysis of auxiliary problems. To reduce computational costs, a hybrid method based on the synthesis of the model and Boltzmann equations is proposed.