arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2003.02296math.NAcs.NA
收藏

分裂形式ALE间断Galerkin方法及其在欠分辨湍流低马赫数流中的应用

Split form ALE discontinuous Galerkin methods with applications to under-resolved turbulent low-Mach number flows

Nico Krais, Gero Schnücke, Thomas Bolemann, Gregor Gassner

摘要:

可压缩Euler或Navier-斯托克斯方程(NSE)的间断Galerkin(DG)方法的构造包括对体积积分中的非线性通量项的近似。在中等马赫数(Ma < 0.3)的湍流模拟中,这些项可能导致混叠和稳定性问题,例如,由于大涡模拟(LES)中典型的涡主导结构分辨率不足。动能或熵在受混叠影响的解决方案的平滑但欠解析部分中升高。众所周知,动能对于可压缩流不是守恒量,但对于小马赫数,可以预期会有与守恒演化的微小偏差。虽然形式上可以构造欧拉方程的动能守恒(KEP)和熵守恒(EC)DG方法,但由于NSE中的粘性项,我们的目标是在移动曲面六面体网格上构造动能耗散(KED)或熵稳定(ES)DG方法。任意拉格朗日-欧拉(ALE)方法被用来包括网格运动的分裂形式DG方法的影响。首先,我们使用三维泰勒-格林涡研究和分析我们的理论研究结果和新的分裂形式ALE DG格式的湍流涡主导流的行为。其次,我们将该框架应用于一个复杂的空气动力学应用。采用隐式LES分裂形式ALE DG方法模拟了雷诺数Re = 40,000、马赫数Ma = 0.1条件下SD 7003翼型的过渡流场。我们比较了标准的节点ALE DG计划,ALE DG变种一致的过度整合的非线性项和新的KED和ES分裂形式ALE DG方法的鲁棒性,准确性和计算效率。

英文摘要:

The construction of discontinuous Galerkin (DG) methods for the compressible Euler or Navier-Stokes equations (NSE) includes the approximation of non-linear flux terms in the volume integrals. The terms can lead to aliasing and stability issues in turbulence simulations with moderate Mach numbers (Ma < 0.3), e.g. due to under-resolution of vortical dominated structures typical in large eddy simulations (LES). The kinetic energy or entropy are elevated in smooth, but under-resolved parts of the solution which are affected by aliasing. It is known that the kinetic energy is not a conserved quantity for compressible flows, but for small Mach numbers minor deviations from a conserved evolution can be expected. While it is formally possible to construct kinetic energy preserving (KEP) and entropy conserving (EC) DG methods for the Euler equations, due to the viscous terms in case of the NSE, we aim to construct kinetic energy dissipative (KED) or entropy stable (ES) DG methods on moving curved hexahedral meshes. The Arbitrary Lagrangian-Eulerian (ALE) approach is used to include the effect of mesh motion in the split form DG methods. First, we use the three dimensional Taylor-Green vortex to investigate and analyze our theoretical findings and the behavior of the novel split form ALE DG schemes for a turbulent vortical dominated flow. Second, we apply the framework to a complex aerodynamics application. An implicit LES split form ALE DG approach is used to simulate the transitional flow around a plunging SD7003 airfoil at Reynolds number Re = 40, 000 and Mach number Ma = 0.1. We compare the standard nodal ALE DG scheme, the ALE DG variant with consistent overintegration of the non-linear terms and the novel KED and ES split form ALE DG methods in terms of robustness, accuracy and computational efficiency.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑