General synthetic iterative scheme for polyatomic rarefied gas flows

Zeng，Jianan; Yuan，Ruifeng; Zhang，Yanbing; Li，Qi; Wu，Lei

2023-10-30

10.1016/j.compfluid.2023.105998

Computers and Fluids   Impact Factor & Quartile

0045-7930

1879-0747

Recently, the general synthetic iterative scheme (GSIS) has been proposed to solve the Boltzmann equation efficiently and accurately in the whole range of gas rarefaction. Here, the GSIS is extended and further improved to find the steady-state solutions in nonlinear polyatomic gas flows. The numerical method is developed within the unstructured finite volume framework, where the kinetic equation and synthetic equations are solved alternately. The synthetic equations, which are derived from the modified Rykov kinetic model, reduce to the two-temperature (translational and rotational) Navier–Stokes–Fourier equations in the continuum flow regime, and include high-order constitutive relations for rarefaction effects in other flow regimes. These high-order terms are obtained by solving the kinetic model with the discrete velocity method. When the synthetic equations are solved, their macroscopic quantities are used to guide the evolution of velocity distribution functions in the kinetic model. As a consequence of this two-way coupling, GSIS not only finds steady-state solutions quickly but also relieves the constraints on spatial cell size. Furthermore, the robustness of GSIS is improved by modifying the boundary macroscopic fluxes in the macroscopic implicit iteration. The efficiency and multiscale property of GSIS is demonstrated through several challenging test cases, including the one-dimensional normal shock wave with large internal-translational relaxation times, the two-dimensional hypersonic flow passing a cylinder, and the pump-driven flow in Europe's demonstration fusion power plant.

Asymptotic preserving Fast convergence General synthetic iterative scheme Polyatomic rarefied gas flow

SCI

English

First ; Corresponding

National Natural Science Foundation of China[12172162];

Computer Science ; Mechanics

Computer Science, Interdisciplinary Applications ; Mechanics

WOS:001048435300001

PERGAMON-ELSEVIER SCIENCE LTD

COMPUTER SCIENCE

2-s2.0-85165538620

Scopus

Department of Mechanics and Aerospace Engineering,Southern University of Science and Technology,Shenzhen,518055,China

Zeng，Jianan,Yuan，Ruifeng,Zhang，Yanbing,et al. General synthetic iterative scheme for polyatomic rarefied gas flows[J]. Computers and Fluids,2023,265.

Zeng，Jianan,Yuan，Ruifeng,Zhang，Yanbing,Li，Qi,&Wu，Lei.(2023).General synthetic iterative scheme for polyatomic rarefied gas flows.Computers and Fluids,265.

Zeng，Jianan,et al."General synthetic iterative scheme for polyatomic rarefied gas flows".Computers and Fluids 265(2023).