论文标题

将模态滤波应用于不连续的光谱元素方法中,以模拟不同雷诺数的可压缩通道流动

Application of Modal Filtering in Discontinuous Spectral Element Method for Simulation of Compressible Channel Flow at Different Reynolds Numbers

论文作者

Peyvan, Ahmad, Ghiasi, Zia, Li, Dongru, Komperda, Jonathan, Mashayek, Farzad

论文摘要

对不可压缩湍流的大涡模拟已得到广泛研究。因此,已经开发了适合不同数值方案的各种模型。在可压缩流动的情况下,由于过滤后的Navier-Stokes方程中出现了许多术语,因此建模更具挑战性。最近,在不连续的光谱元素方法(DSEM)中实现了模态显式滤波,以模拟可压缩流的子滤光尺度的影响。该方法在计算上是便宜的,因为它是使用良好的数学库在DSEM代码中实现的。它已成功地应用于可压缩衰减的各向同性湍流和湍流流量的模拟。在这项研究中,使用DSEM中的显式模态过滤模拟了具有三种不同摩擦雷诺数的通道流,通过比较湍流统计统计和摩擦雷诺数与DNS的数字来评估新方法的性能。该模型可预测摩擦雷诺数,相对于DNS,误差最大为2.16%。尽管与DNS相比,该模型为平均速度曲线产生了有希望的结果,但它需要调整滤波器强度和频率才能准确预测RMS统计。

Large-eddy simulation of incompressible turbulent flow has been extensively investigated; hence, a variety of models suited for different numerical schemes have been developed. In the case of compressible flow, the modeling is more challenging due to the numerous terms that arise in the filtered Navier-Stokes equations. Recently, modal explicit filtering was implemented in the discontinuous spectral element method (DSEM) to mimic the effects of sub-filtered scales for compressible flows. The method is computationally inexpensive since it is implemented in the DSEM code using a well-established math library. It has been successfully applied to simulations of compressible decaying isotropic turbulence and turbulent channel flow. In this study, channel flows with three different friction Reynolds numbers are simulated using explicit modal filtering in DSEM to assess the performance of the new method by comparing turbulent statistics and friction Reynolds numbers to those from DNS. The model predicts the friction Reynolds number with a maximum of 2.16% error with respect to DNS. Although the model generates promising results for the average velocity profile compared to DNS, it requires adjustment of filter strength and frequency to predict rms statistics accurately.

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