Visualization of Vortex Field of 2-D Flapping Wing Motion
Visualization of Vortex Field of 2-D Flapping Wing Motion
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发表时间：
2005
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通讯作者：
Yang Ji-ming
中科院分区：
文献类型：
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作者：
Yang Ji-ming
在二维模型实验系统上对扑翼运动进行了实验研究。利用DPIV流场显示技术对低雷诺数下扑翼运动的涡场进行了研究。对不同的扫掠速度、旋后/旋前旋转速度和攻角等控制参数以及推进、对称和延迟三种相位运动模式进行了实验。研究发现，在翼型的整个行程中，后缘涡不断被冲刷到尾流中，前缘涡则附着在翼型表面，这是翼型升力产生的主要机制。在均匀行程运动阶段，迎角低于15°的情况下没有观察到前缘涡。迎角在30° ~ 50°时，前缘涡形成明显，并附着在翼面上。当迎角大于50°时，前缘涡将迅速形成，并在形成后很快从翼面分离。三种运动方式的流场各不相同，在上升冲程和下降冲程的早期，前缘涡的运动有两种类型。
An experimental study of flapping wing motion was conducted in a 2-D model test system. DPIV based flow visualization was carried out to examine the vortex field around the flapping wing, whose motion is at a low Reynolds number. The experiments were conducted for various controlling parameters, such as different sweeping velocities, supination/pronation rotational speeds and angels of attack, as well as the three phase motion patterns, namely, advance, symmetry and delay patterns. It was found that the trailing-edge vortex is washed away continuously into the wake flow during the stroke, and the leading-edge vortex attached to the foil surface, which is the main mechanism for the generation of lift force. During the uniform stroke motion stage, no leading-edge vortex was observed for those cases in which angles of attack are below 15°. The leading-edge vortex is formed obviously and attached to the wing surface when the angles of attack are between 30° and 50°. If the angle of attack is above 50°, the leading-edge vortex will be quickly formed and separated from the wing surface soon after the formation. The flow fields are different for the three phase motion patterns and there are two types of leading-edge vortex motion at an earlier stage of upstroke or downstroke.