Subgrid-scale pressure field of scale-enriched large eddy simulations using Gabor modes
Subgrid-scale pressure field of scale-enriched large eddy simulations using Gabor modes
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DOI：
10.1103/physrevfluids.6.124607
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发表时间：
2020-12
影响因子：
2.7
通讯作者：
Ryan Hass;A. Ghate;S. Lele
中科院分区：
文献类型：
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作者：
Ryan Hass;A. Ghate;S. Lele
随着大涡模拟（LES）技术的不断发展和计算资源的不断增加，数值求解各种流动中的时变、各向异性大尺度湍流已成为可能。对于某些应用，这种大尺度分辨率是令人满意的。然而，广泛的工程问题涉及在非常大的雷诺数下的流动，其中实际LES的亚网格尺度动力学对于设计是至关重要的，并且在给定求解Navier Stokes方程的计算需求的情况下是无法达到的;这种困难在壁边界湍流中尤其相关，在壁边界湍流中，即使大尺度也常常低于适度成本壁建模LES（WMLES）的隐含滤波器宽度。在本文中，我们简要地介绍了一个规模丰富的过程，利用空间和光谱本地化的Gabor模式。该方法提供了一个物理上一致的小尺度速度场的描述，而无需求解完整的非线性方程组。浓缩过程的能力进行评估，以预测小规模的压力场的贡献。我们发现，该方法准确地外推的压力谱和恢复压力变化的全场显着相比，计算昂贵，高分辨率LES。分析进行了先验和后验设置的情况下，均匀各向同性湍流（HIT）。
With the continuing progress in large eddy simulations (LES), and ever increasing computational resources, it is currently possible to numerically solve the time-dependent and anisotropic large scales of turbulence in a large variety of flows. For some applications this large-scale resolution is satisfactory. However, a wide range of engineering problems involve flows at very large Reynolds numbers where the subgrid scale dynamics of a practical LES are critically important to design and yet are out of reach given the computational demands of solving the Navier Stokes equations; this difficulty is particularly relevant in wall-bounded turbulence where even the large-scales are often below the implied filter width of modest cost wall modeled LES (WMLES). In this paper we briefly introduce a scale enrichment procedure which leverages spatially and spectrally-localized Gabor modes. The method provides a physically consistent description of the small scale velocity field without solving the full non-linear equations. The enrichment procedure is appraised against its ability to predict small scale contributions to the pressure field. We find that the method accurately extrapolates the pressure spectrum and recovers pressure variance of the full field remarkably well when compared to a computationally expensive, highly resolved LES. The analysis is conducted both in a priori and a posteriori settings for the case of homogeneous isotropic turbulence (HIT).