Time-resolved wake structure and kinematics of bat flight
Time-resolved wake structure and kinematics of bat flight
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DOI：
10.1007/s00348-009-0624-7
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发表时间：
2009-05-01
影响因子：
2.4
通讯作者：
Breuer, Kenneth S.
中科院分区：
文献类型：
--
作者：
Hubel, Tatjana Y.;Hristov, Nickolay I.;Breuer, Kenneth S.
我们提出了同步的时间分辨测量的机翼运动学和尾流速度为中等大小的蝙蝠，Cynopterus brachyotis，在低中低速飞行在一个封闭的返回风洞。在200 Hz下记录机身和机翼连接处的运动测量值以及Trefftz平面中的合成尾流速度（每个机翼拍约28-31次测量值）。虽然在尾涡结构中可以看到飞行剖面的变化，但发现环流剖面是完全可重复的。在翼拍的中半部分（根据手腕的垂直运动定义，从下划开始），循环的强度几乎恒定。一个强大的流向涡被观察到从翼尖脱落，在下降行程中的强度增长，并在上升行程的大部分时间持续存在。在相对较低的飞行速度（4.3米/秒），一个封闭的涡流结构背后的蝙蝠被假定。
We present synchronized time-resolved measurements of the wing kinematics and wake velocities for a medium sized bat, Cynopterus brachyotis, flying at low-medium speed in a closed-return wind tunnel. Measurements of the motion of the body and wing joints, as well as the resultant wake velocities in the Trefftz plane are recorded at 200 Hz (approximately 28-31 measurements per wing beat). Circulation profiles are found to be quite repeatable although variations in the flight profile are visible in the wake vortex structures. The circulation has almost constant strength over the middle half of the wing beat (defined according the vertical motion of the wrist, beginning with the downstroke). A strong streamwise vortex is observed to be shed from the wingtip, growing in strength during the downstroke, and persisting during much of the upstroke. At relatively low flight speeds (4.3 m/s), a closed vortex structure behind the bat is postulated.