Journal of Computational Physics ( IF 4.1 ) Pub Date : 2021-05-05 , DOI: 10.1016/j.jcp.2021.110402 Guiyu Cao , Liang Pan , Kun Xu
The direct numerical simulation (DNS) of compressible isotropic turbulence up to the supersonic regime with has been investigated by the high-order gas-kinetic scheme (HGKS) (Cao et al. (2019) [8]). In this study, the DNS on a much higher initial turbulent Mach number up to is performed by HGKS, which confirms the super robustness of HGKS. The coarse-graining analysis of subgrid-scale (SGS) turbulent kinetic energy budget is fully analyzed for constructing one-equation SGS model in the compressible large eddy simulation (LES). The exact compressible SGS turbulent kinetic energy transport equation is derived with density weighted filtering process. Based on the compressible transport equation, the coarse-graining processes are implemented on three sets of unresolved grids with the Box filter. The coarse-graining analysis of compressible budgets shows that all unresolved source terms are dominant in the current system. Especially, the magnitude of SGS pressure-dilation term is on the order of SGS solenoidal dissipation term within the initial acoustic time scale. Therefore, the SGS pressure-dilation term cannot be neglected as that in the previous work. The delicate coarse-graining analysis of SGS diffusion terms in compressible equation also confirms that both the fluctuation velocity triple correlation term and the pressure-velocity correlation term are dominant terms. The current analysis provides an indication on the order of magnitude of all SGS terms in compressible budget, which provides a solid basis for compressible LES modeling of high Mach number turbulent flow.
中文翻译:
超音速各向同性湍流的三维高阶气体动力学方案II:可压缩K sgs预算的粗粒度分析
可压缩各向同性湍流直至超音速状态的直接数值模拟(DNS) 已通过高阶气体动力学方案(HGKS)进行了研究(Cao等人(2019)[8])。在这项研究中,DNS的初始湍流马赫数更高由HGKS执行,这证实了HGKS的超强耐用性。亚网格规模(SGS)湍动能的粗粒度分析在可压缩大涡模拟(LES)中,对预算进行了全面分析,以构建一方程式SGS模型。精确可压缩的SGS湍动能输运方程是通过密度加权滤波过程得出的。基于可压缩在输运方程中,使用Box过滤器在三组未解析的网格上执行粗粒度处理。可压缩物的粗粒度分析预算显示,所有未解决的源术语在当前系统中均占主导地位。特别地,在初始声学时间标度内,SGS压力膨胀项的量级为SGS螺线管耗散项的量级。因此,不能像以前的工作那样忽略SGS压力膨胀项。可压缩SGS扩散项的精细粗粒度分析该方程还证实了波动速度三次相关项和压力-速度相关项都是主导项。当前分析提供了所有可压缩SGS项的数量级指示 预算,这为高马赫数湍流的可压缩LES建模提供了坚实的基础。