论文标题
各种比例相似模型在稳定的混合亚网格尺度模型中的作用
Role of various scale-similarity models in stabilized mixed subgrid-scale model
论文作者
论文摘要
我们研究了稳定的混合模型中各种比例相似模型的身体作用[K.安倍，国际。 J.热流动流，39，42（2013）; M. Inagaki和K. Abe，Int。 J.热流体流量，64，137（2017）]，并评估其在湍流通道流中的性能。在本研究中的各种模型中，原始模型与亚网格尺度（SGS） - Reynolds项的比例相似模型相似，从而可以最佳预测网格尺度（GS）速度波动的各向异性和SGS的压力，即使在粗网格分辨率中，也是SGS的压力。此外，它成功地预测了根据过滤的直接数值模拟接近截止尺度的光谱的大强度，而其他模型则预测了低波长区域中光谱的迅速衰减。为了研究接近截止量表的模型的行为，我们分析了GS雷诺应力谱的预算方程。结果表明，SGS-Reynolds项的比例相似模型在接近截止尺度的壁正常速度波动的增强中起作用。因此，它激活接近截止尺度的湍流，导致在壁挂式湍流中观察到的适当条纹结构的繁殖。接近截止尺度和湍流结构的速度波动的再现是进一步开发SGS模型的关键要素。
We investigate the physical role of various scale-similarity models in the stabilized mixed model [K. Abe, Int. J. Heat Fluid Flow, 39, 42 (2013); M. Inagaki and K. Abe, Int. J. Heat Fluid Flow, 64, 137 (2017)] and evaluate their performance in turbulent channel flows. Among various models in the present study, the original model combined with the scale-similarity model for the subgrid-scale (SGS)-Reynolds term yields the best prediction for the anisotropy of the grid-scale (GS) velocity fluctuations and the SGS stress, even in coarse grid resolutions. Moreover, it successfully predicts large intensities of the spectra close to the cut-off scale in accordance with the filtered direct numerical simulation, whereas other models predict a rapid decay of the spectra in the low-wavelength region. To investigate the behavior of the models close to the cut-off scale, we analyze the budget equation for the GS Reynolds stress spectrum. The result shows that the scale-similarity model for the SGS-Reynolds term plays a role in the enhancement of the wall-normal velocity fluctuation close to the cut-off scale. Thereby, it activates turbulence close to the cut-off scale, leading to a reproduction of the proper streak structures observed in wall-bounded turbulent flows. The reproduction of velocity fluctuations close to the cut-off scale and turbulent structures is a key element for further development of SGS models.
