Implicit LES of free and wall‐bounded turbulent flows based on the discontinuous Galerkin/symmetric interior penalty method
Implicit LES of free and wall‐bounded turbulent flows based on the discontinuous Galerkin/symmetric interior penalty method
复制标题
基于间断伽辽金/对称内罚法的自由和壁面湍流隐式 LES
DOI：
10.1002/fld.4021
复制
发表时间：
2015
影响因子：
1.8
通讯作者：
G. Winckelmans
中科院分区：
文献类型：
--
作者：
C. C. D. Wiart;K. Hillewaert;L. Bricteux;G. Winckelmans
本文提出了一种用于复杂流动直接数值模拟（DNS）和大涡模拟（LES）的对称内点罚可压缩间断Galerkin求解器（DGM/SIP）的第二验证步骤。该方法已经成功地验证了DNS的学术流，并已被应用到周围的复杂几何形状（如翼型和涡轮叶片）的流动。在这些研究中，该方法的耗散特性的优势得到了强调，显示出仅耗散欠分辨尺度（即网格上存在的最小尺度）的自然趋势，而不影响较大尺度。这种现象随着多项式阶数的增加而进一步增强。事实上，该阶增加了最大波数时的耗散，而其影响范围则减小了。这些属性与亚网格尺度模型在谱上是兼容的，因此DGM可能非常适合用于隐式LES（ILES）方法。本文在正则流上研究了这种DGM/ILES方法的验证，允许研究离散化对欠分辨计算的湍流的影响。第一个测试用例是衰减均匀各向同性湍流（HIT）在非常高的雷诺数LES。该基准允许评估隐式LES方法的谱行为。结果与理论一致，甚至比文献中使用伪谱（PS）方法和最先进的亚网格尺度模型获得的其他数值结果更精确。第二个基准是通道流的LES。考虑三种雷诺数：Reτ=395、590和950。并与Moser等人和Hoyas等人的DNS结果进行了比较，也使用PS方法。平均速度和波动都与参考文献一致，表明该方法能够预测平衡壁面湍流。为了表明该方法能够执行精确的DNS，还执行了在Reλ=64处的HIT的DNS和在Reτ=180处的通道流的DNS。在Reτ=395的槽道流上研究了网格细化的效果，突出了在展向方向细化网格时结果的改善。最后，修改的ILES参数，即黎曼求解器和SIP系数，研究这两种情况下，黎曼求解器的选择上显示出显着的影响。版权所有© 2015约翰威利父子有限公司.
This paper presents the second validation step of a compressible discontinuous Galerkin solver with symmetric interior penalty (DGM/SIP) for the direct numerical simulation (DNS) and the large eddy simulation (LES) of complex flows. The method has already been successfully validated for DNS of an academic flow and has been applied to flows around complex geometries (e.g. airfoils and turbomachinery blades). During these studies, the advantages of the dissipation properties of the method have been highlighted, showing a natural tendency to dissipate only the under‐resolved scales (i.e the smallest scales present on the mesh), leaving the larger scales unaffected. This phenomenon is further enhanced as the polynomial order is increased. Indeed, the order increases the dissipation at the largest wave numbers, while its range of impact is reduced. These properties are spectrally compatible with a subgrid‐scale model, and hence DGM may be well suited to be used for an implicit LES (ILES) approach. A validation of this DGM/ILES approach is here investigated on canonical flows, allowing to study the impact of the discretisation on the turbulence for under‐resolved computations. The first test case is the LES of decaying homogeneous isotropic turbulence (HIT) at very high Reynolds number. This benchmark allows to assess the spectral behaviour of the method for implicit LES. The results are in agreement with theory and are even slightly more accurate than other numerical results from literature, obtained using a pseudo‐spectral (PS) method with a state‐of‐the‐art subgrid‐scale model. The second benchmark is the LES of the channel flow. Three Reynolds numbers are considered: Reτ=395, 590 and 950. The results are compared with DNS of Moser et al. and Hoyas et al., also using PS methods. Both averaged velocity and fluctuations are globally in good agreement with the reference, showing the ability of the method to predict equilibrium wall‐bounded flow turbulence. To show that the method is able to perform accurate DNS, a DNS of HIT at Reλ=64 and a DNS of the channel flow at Reτ=180 are also performed. The effects of the grid refinement are investigated on the channel flow at Reτ=395, highlighting the improvement of the results when refining the mesh in the spanwise direction. Finally, the modification of the ILES parameters, that is the Riemann solver and of the SIP coefficient, is studied on both cases, showing a significant influence on the choice of the Riemann solver. Copyright © 2015 John Wiley & Sons, Ltd.
影响因子：
3.4
作者：
Gassner, Gregor J.;Beck, Andrea D.
通讯作者：
Beck, Andrea D.