An efficient direct solver for rarefied gas flows with arbitrary statistics

作者：Diaz Manuel A; Yang Jaw Yen^*

来源：Journal of Computational Physics, 2016, 305: 127-149.

DOI：10.1016/j.jcp.2015.09.003

• Quantum rarefied gas dynamics
• Semi-classical Boltzmann equation
• Bhatnagar-Gross-Krook
• Asymptotic preserving
• Weighted essentially non-oscillatory

A new numerical methodology associated with a unified treatment is presented to solve the Boltzmann-BGK equation of gas dynamics for the classical and quantum gases described by the Bose-Einstein and Fermi-Dirac statistics. Utilizing a class of globally-stiffly-accurate implicit-explicit Runge-Kutta scheme for the temporal evolution, associated with the discrete ordinate method for the quadratures in the momentum space and the weighted essentially non-oscillatory method for the spatial discretization, the proposed scheme is asymptotic-preservingand imposes no non-linear solver or requires the knowledge of fugacity and temperature to capture the flow structures in the hydrodynamic (Euler) limit. The proposed treatment overcomes the limitations found in the work by Yang and Muljadi (2011) [33] due to the non-linear nature of quantum relations, and can be applied in studying the dynamics of a gas with internal degrees of freedom with correct values of the ratio of specific heat for the flow regimes for all Knudsen numbers and energy wave lengths. The present methodology is numerically validated with the unified treatment by the one-dimensional shock tube problem and the two-dimensional Riemann problems for gases of arbitrary statistics. Descriptions of ideal quantum gases including rotational degrees of freedom have been successfully achieved under the proposed methodology.

• 出版日期2016-1-15