A computational study is conducted to systematically investigate the effect of rotating speed on vortex shedding characteristics and far-field wake patterns of an elliptic foil rotating in uniform cross flows at low Reynolds numbers. It is found that at low rotating speed, vortices shed at the advancing and retreating edges of the foil could form a strong vortex pair in the wake. At high rotating speed, adjacent vortices are closer to each other, thus may evolve into a single vortex. The far-field wake pattern also strongly depends on the rotating speed and demonstrates complex behaviors. It is observed that the wake can defect from downwards to upwards by increasing the rotating speed. The mean lift force increases monotonically with the rotating speed, while a significant drag reduction occurs at a small rotating speed, which is explained by the corresponding wake pattern. Furthermore, a rotating speed regime exists in which the mean aerodynamic torque is positive so that the ...

中文翻译：

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椭圆箔以低雷诺数均匀流动旋转

进行了一项计算研究，系统地研究了转速对低雷诺数下以均匀横流旋转的椭圆形箔片的涡旋脱落特性和远场尾迹图形的影响。已经发现，在低转速下，在箔片的前进和后退边缘掉落的涡流可能在尾流中形成强的涡流对。在高转速下，相邻的涡流彼此更靠近，因此可能演变成单个涡流。远场唤醒模式也强烈取决于旋转速度，并表现出复杂的行为。观察到，通过增加旋转速度，尾流可以从下到上出现缺陷。平均升力随转速单调增加，而在小转速下阻力显着降低，这由相应的唤醒模式解释。此外，存在一个转速范围，其中平均空气动力学转矩为正，因此...