Direct numerical simulation of a three‐dimensional turbulent boundary layer
Direct numerical simulation of a three‐dimensional turbulent boundary layer
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三维湍流边界层的直接数值模拟
DOI：
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发表时间：
1990
期刊：
影响因子：
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通讯作者：
N. Mansour
中科院分区：
文献类型：
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作者：
P. Moin;T. Shih;D. Driver;N. Mansour
在平面槽道流动的直接数值模拟中，研究了横向应变对初始二维湍流边界层的影响。数值模拟结果与三维边界层实验结果一致，表明雷诺剪应力随横向应变的增大而减小。此外，雷诺剪应力矢量和平均速度梯度矢量的方向也不同。此外，模拟还显示出湍流动能的下降。计算了雷诺应力输运方程中的项。平衡结果表明，湍流动能的降低是湍流产生量减少、湍流耗散增加的结果。直觉推理和当前的湍流模型将预测动能的增加，以及由于平均流应变率增加而导致的生产和耗散率的增加。在流动演化的后期，湍流的产生和耗散都有所增加。
The effects of transverse strain on an initially two‐dimensional turbulent boundary layer are studied in a direct numerical simulation of a planar channel flow with impulsively started transverse pressure gradient. Consistent with experiments in three‐dimensional boundary layers, the simulation shows a decrease in the Reynolds shear stress with increasing transverse strain. Also, the directions of the Reynolds shear stress vector and the mean velocity gradient vector were found to differ. In addition, the simulation shows a drop in the turbulent kinetic energy. Terms in the Reynolds stress transport equations were computed. The balances indicate that the decrease in turbulent kinetic energy is a result of a decrease in turbulence production, along with an increase in turbulent dissipation. Intuitive reasoning and current turbulence models would predict an increase in kinetic energy along with increases in production and dissipation rates as a result of increased mean‐flow strain rate. Later in the evolution of the flow, both turbulence production and dissipation increase.