An extended hybrid numerical simulation of isotropic compressible turbulence

TL;DR

This paper extends a hybrid numerical scheme for simulating isotropic compressible turbulence to higher Mach numbers, improving robustness and accuracy with new techniques and confirming effectiveness through numerical results.

Contribution

The paper introduces a robust extension of a hybrid scheme for high Mach number turbulence simulation, incorporating new reconstruction failure detection and a positivity-preserving cooling function.

Findings

Extended the hybrid scheme to higher turbulent Mach numbers

Enhanced robustness with new failure detection criterion

Confirmed improved performance through numerical tests

Abstract

This paper presents an extension of the hybrid scheme proposed by Wang et al. (J. Comput. Phys. 229 (2010) 169-180) for numerical simulation of compressible isotropic turbulence to flows with higher turbulent Mach numbers. The scheme still utilizes an 8th-order compact scheme with built-in hyperviscosity for smooth regions and a 7th-order WENO scheme for highly compressive regions, but now both in their conservation formulations and for the latter with the Roe type characteristic-wise reconstruction. To enhance the robustness of the WENO scheme without compromising its high-resolution and accuracy, the recursive-order-reduction procedure is adopted, where a new type of reconstruction-failure-detection criterion is constructed. To capture the upwind direction properly in extreme conditions, the global Lax-Friedrichs numerical flux is used. In addition, a new form of cooling function is proposed, which is proved to be positivity-preserving. With these techniques, the new scheme not only inherits the good properties of the original one but also extends largely the computable range of turbulent Mach number, which has been further confirmed by numerical results.