TY - JOUR
T1 - A Gas-Kinetic Unified Algorithm for Non-Equilibrium Polyatomic Gas Flows Covering Various Flow Regimes
AU - Hu , Wen-Qiang
AU - Li , Zhi-Hui
AU - Peng , Ao-Ping
AU - Jiang , Xin-Yu
JO - Communications in Computational Physics
VL - 1
SP - 144
EP - 189
PY - 2021
DA - 2021/04
SN - 30
DO - http://doi.org/10.4208/cicp.OA-2020-0122
UR - https://global-sci.org/intro/article_detail/cicp/18877.html
KW - Gas-kinetic unified algorithm, polyatomic gas, ellipsoidal statistical model, conservative discrete velocity ordinate method, implicit scheme.
AB - <p style="text-align: justify;">In this paper, a gas-kinetic unified algorithm (GKUA) is developed to investigate the non-equilibrium polyatomic gas flows covering various regimes. Based
on the ellipsoidal statistical model with rotational energy excitation, the computable
modelling equation is presented by unifying expressions on the molecular collision relaxing parameter and the local equilibrium distribution function. By constructing the
corresponding conservative discrete velocity ordinate method for this model, the conservative properties during the collision procedure are preserved at the discrete level
by the numerical method, decreasing the computational storage and time. Explicit
and implicit lower-upper symmetric Gauss-Seidel schemes are constructed to solve
the discrete hyperbolic conservation equations directly. Applying the new GKUA,
some numerical examples are simulated, including the Sod Riemann problem, homogeneous flow rotational relaxation, normal shock structure, Fourier and Couette flows,
supersonic flows past a circular cylinder, and hypersonic flow around a plate placed
normally. The results obtained by the analytic, experimental, direct simulation Monte
Carlo method, and other measurements in references are compared with the GKUA
results, which are in good agreement, demonstrating the high accuracy of the present
algorithm. Especially, some polyatomic gas non-equilibrium phenomena are observed
and analysed by solving the Boltzmann-type velocity distribution function equation
covering various flow regimes.</p>