具有纵向肋条的通道流中的二次流和近壁湍流
Secondary Flows and Near-Wall Turbulence in Channel Flow with Longitudinal Ribs
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中文总结 AI 辅助
该研究用大涡模拟研究通道流中矩形和三角形纵向肋条引发的二次流及近壁湍流，设定摩擦雷诺数等参数，对比了两种肋条情况下的涡旋、粗糙度函数、壁面剪切应力、雷诺应力等，发现不同特性及规律。
中文摘要 AI 辅助
本研究采用大涡模拟（LES）来研究通道流中由两种表面安装的纵向肋条（即矩形和三角形）引起的二次流和近壁湍流。基于摩擦速度和通道高度H的摩擦雷诺数设定为220。肋条的宽高比W/h（其中W和h分别代表肋条的宽度和高度）为2，肋条间距S为0.6H。结果表明，在所考虑的两种情况下，相邻肋条之间都形成了两个反向旋转的涡旋。矩形肋条的粗糙度函数比三角形肋条的更高。在矩形肋条的中平面位置，壁面剪切应力比肋条之间中平面位置的相对较低。相反，对于三角形肋条的情况，观察到相反的模式。两种情况下，法向雷诺应力在壁面附近都表现出强烈的各向异性行为，在0.4H以上重叠。在0.4H和0.8H之间，法向雷诺应力的变化是线性的。在壁面附近，与矩形肋条相比，三角形肋条观察到更高的湍动能（TKE）和法向雷诺应力产生。在对数律区域，产生与耗散的比率为1。
英文摘要
This study employs the Large Eddy Simulation (LES) to investigate secondary flows and near-wall turbulence induced by two types of surface-mounted longitudinal ribs, namely rectangular and triangular, in a channel flow. The friction Reynolds number, based on friction velocity and channel height H, is set at 220. The rib aspect ratio W/h, where W and h represent the width and height of the rib, is 2, and the rib spacing, S is 0.6H. The results indicate formation of two counter-rotating vortices between the adjacent ribs for both the cases considered. The roughness function is higher with the rectangular rib as compared to that of the triangular rib. At the location of the mid-plane on the rectangular ribs, the wall shear stress is relatively lower as compared to that of the location of mid-plane between the ribs. Conversely, for the case of triangular rib, the opposite pattern is observed. Normal Reynolds stress exhibits strong anisotropic behaviour near the wall for both the cases, overlapping above 0.4H. Between 0.4H and 0.8H, the variation in normal Reynolds stresses is linear. Near the wall, higher production of turbulent kinetic energy (TKE) and normal Reynolds stresses are observed with the triangular rib as compared to those of the rectangular rib. The ratio of production to dissipation is unity in the log-law region.
