Аннотация:This study is devoted to the two-dimensional numerical simulation of the gas flow transition regime with solid wall interaction. Regularized 13-moment Grad’s set of equations (R13) [1,2] and Unified Gas-Kinetic Scheme (UGKS) [3, 4] were chosen as a mathematical models for further comparison of the results.
The variant of explicit high resolution Godunov scheme with linear flow parameter reconstruction is used for numerical solution of the R13 set of equations. Five so-called kinetic boundary conditions are taken as a base of mathematical model of isothermal solid wall [5]. The complete set of wall boundary conditions is obtained by an approximation of the selected subset of the R13 bulk equations. The final set of nonlinear equations on the wall is solved with Newton’s numerical method [6].
Our implementation of the UGKS follows [3,4] in the basic details, and allows to calculate continuum and rarefied flows in geometrically complex regions.
Both models are tested extensively on many well-known test cases. In this paper we present the results ob-tained by the two models, for the three problems: Poiseuille flow, lid-cavity problem and Knudsen compressor. The obtained results are compared with published in the literature results from other methods. There is a good coincidence of the results in case of Knudsen number is smaller than 0.5 (Kn<0.5).