We analyze schemes based on a general Implicit-Explicit (IMEX) time discretization for the compressible Euler equations of gas dynamics, showing that they are asymptotic-preserving (AP) in the low Mach number limit. The analysis is carried out for a general equation of state (EOS). We consider both a single asymptotic length scale and two length scales. We then show that, when coupling these time discretizations with a Discontinuous Galerkin (DG) space discretization with appropriate fluxes, a numerical method effective for a wide range of Mach numbers is obtained. A number of benchmarks for ideal gases and their non-trivial extension to non-ideal EOS validate the performed analysis.
翻译:本文分析了基于一般隐式-显式(IMEX)时间离散格式的数值方法在气体动力学可压缩欧拉方程中的应用,证明了这些格式在低马赫数极限下具有渐近保持(AP)特性。该分析针对一般状态方程(EOS)展开,分别考察了单一渐近长度尺度与双重长度尺度的情况。研究表明,当此类时间离散格式与采用适当通量的间断伽辽金(DG)空间离散格式耦合时,可获得适用于宽马赫数范围的有效数值方法。针对理想气体的若干基准测试及其向非理想状态方程的非平凡扩展,验证了所完成分析的有效性。