The aerodynamic forces acting on a revolving dried pigeon wing and a flat card replica were measured with a propeller rig, effectively simulating a wing in continual downstroke. Two methods were adopted: direct measurement of the reaction vertical force and torque via a forceplate, and a map of the pressures along and across the wing measured with differential pressure sensors. Wings were tested at Reynolds numbers up to 108,000, typical for slow-flying pigeons, and considerably above previous similar measurements applied to insect and hummingbird wing and wing models. The pigeon wing out-performed the flat card replica, reaching lift coefficients of 1.64 compared with 1.44. Both real and model wings achieved much higher maximum lift coefficients, and at much higher geometric angles of attack (43°), than would be expected from wings tested in a windtunnel simulating translating flight. It therefore appears that some high-lift mechanisms, possibly analogous to those of slow-flying insects, may be available for birds flapping with wings at high angles of attack. The net magnitude and orientation of aerodynamic forces acting on a revolving pigeon wing can be determined from the differential pressure maps with a moderate degree of precision. With increasing angle of attack, variability in the pressure signals suddenly increases at an angle of attack between 33° and 38°, close to the angle of highest vertical force coefficient or lift coefficient; stall appears to be delayed compared with measurements from wings in windtunnels.

中文翻译：

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旋转鸽翼的空气动力和压力分布

用螺旋桨装置测量作用在旋转的干燥鸽翼和平面卡片复制品上的空气动力，有效地模拟了连续下冲程的机翼。采用了两种方法：通过测力板直接测量反作用垂直力和扭矩，以及使用压差传感器测量沿机翼和机翼两侧的压力图。翅膀在雷诺数高达 108,000 的情况下进行了测试，这对于慢速飞行的鸽子来说是典型的，并且大大高于之前应用于昆虫和蜂鸟翅膀和翅膀模型的类似测量值。鸽翼表现优于平卡复制品，升力系数为 1.64，而升力系数为 1.44。真实机翼和模型机翼都实现了更高的最大升力系数，以及更高的几何攻角 (43°)，比在模拟平移飞行的风洞中测试的机翼所预期的要高。因此，似乎一些高升力机制，可能类似于慢速飞行的昆虫，可能适用于以高迎角扇动翅膀的鸟类。作用在旋转鸽翼上的空气动力的净大小和方向可以从具有中等精度的压差图确定。随着迎角的增加，压力信号的变化在33°和38°之间的迎角处突然增加，接近最高垂直力系数或升力系数的角度；与风洞中机翼的测量值相比，失速似乎有所延迟。可能类似于那些慢速飞行的昆虫，可能适用于以高迎角扇动翅膀的鸟类。作用在旋转鸽翼上的空气动力的净大小和方向可以从具有中等精度的压差图确定。随着迎角的增加，压力信号的变化在33°和38°之间的迎角处突然增加，接近最高垂直力系数或升力系数的角度；与风洞中机翼的测量值相比，失速似乎有所延迟。可能类似于那些慢速飞行的昆虫，可能适用于以高迎角扇动翅膀的鸟类。作用在旋转鸽翼上的空气动力的净大小和方向可以从具有中等精度的压差图确定。随着迎角的增加，压力信号的变化在33°和38°之间的迎角处突然增加，接近最高垂直力系数或升力系数的角度；与风洞中机翼的测量值相比，失速似乎有所延迟。作用在旋转鸽翼上的空气动力的净大小和方向可以从具有中等精度的压差图确定。随着迎角的增加，压力信号的变化在33°和38°之间的迎角处突然增加，接近最高垂直力系数或升力系数的角度；与风洞中机翼的测量值相比，失速似乎有所延迟。作用在旋转鸽翼上的空气动力的净大小和方向可以从具有中等精度的压差图确定。随着迎角的增加，压力信号的变化在33°和38°之间的迎角处突然增加，接近最高垂直力系数或升力系数的角度；与风洞中机翼的测量值相比，失速似乎有所延迟。