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Passive Control of Vortex Shedding and Drag Reduction in Laminar Flow across Circular Cylinder Using Wavy Wall Channel
Fluid Dynamics ( IF 0.9 ) Pub Date : 2021-03-14 , DOI: 10.1134/s0015462821010067
L. Hussain , M. M. Khan

Abstract—

Numerical simulations of incompressible laminar flow past a circular cylinder using wavy wall confinement are performed in order to study drag reduction and vortex shedding suppression for Reynolds numbers (50 ≤ Re ≤ 280) and blockage ratios (0.5 ≤ D/H ≤ 0.9), where D is the cylinder diameter and H is the channel height. The optimum configuration of wavy wall confinement is identified to have an amplitude of 0.2D and wavelength of 4D which manifests the minimum drag coefficient and complete vortex shedding suppression (zero lift coefficient). The flow over the cylinder with optimized wavy wall confinement produces a stable vortex pair in the wake of the cylinder. The length of vortex pair in the wake increases by increasing the Reynolds number and decreasing the blockage ratio. The drag on the cylinder reduces when the length of vortex pair increases due to early flow separation and reduction in pressure drag. The drag coefficient decreases by 36% in comparison to the plane wall confinement at D/H = 0.5. The drag coefficient decreases for wavy wall configuration by about 67% for D/H = 0.7 and 94% for D/H = 0.9. The lift coefficient remains zero at all Reynolds numbers and blockage ratios which indicates complete suppression of vortex shedding.



中文翻译:

波浪壁通道被动控制涡流脱落和减少层流绕过圆柱的层流

摘要-

不可压缩层流过去使用波状壁限制的圆柱的数值模拟,以便执行以研究减阻和涡旋脱落抑制为雷诺数(50≤重新≤280)和阻塞比(0.5≤ d / ħ ≤0.9),其中D是圆柱直径,H是通道高度。确定波浪壁限制的最佳配置具有0.2 D的振幅和4 D的波长表现出最小的阻力系数和完全的涡旋脱落抑制(零升力系数)。经过优化的波浪形壁面限制的圆柱体上的流动会在圆柱体尾部产生稳定的涡流对。尾流中涡流对的长度通过增加雷诺数和减小阻塞率而增加。当涡流对的长度由于早期流动分离和压力阻力的减小而增加时,气缸上的阻力减小。与D / H = 0.5时的平面壁约束相比,阻力系数降低了36%。阻力系数由约67%为波状壁配置减小d / ħ = 0.7和94%为d / ħ= 0.9。在所有雷诺数和阻塞率下,升力系数均保持为零,这表明涡流脱落得到了完全抑制。

更新日期:2021-03-15
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