食蚜蝇悬停飞行时的气动特性

用数值求解N-S(Navier-Stokes)方程的方法得到了食蚜蝇在拍动平面倾斜悬停飞行时的气动力和气动力矩,利用得到的气动力矩和已知的翅膀的惯性矩求得食蚜蝇悬停时的能耗,并将得到的气动力和能耗与正常悬停时的进行比较.主要结果为:维持食蚜蝇体重所需的举力主要由下拍产生,该举力是由翅膀的升力和阻力共同贡献的,这两点均与水平拍动的情形不同;飞行的比功率为31.71 W·kg^-1,与正常悬停时接近,这表明此种悬停方式有便于进行机动飞行的优点,但不带来额外的能耗.

Aerodynamics of hovering true hoverflies

The aerodynamic force production of true hoverfly which can hover with an inclined stroke plane(body being approximately horizontal) was investigated,using the method of numerically solving the Navier-Stokes equation.The power requirement was computed using the aerodynamic moment and the inertia of the wing.The aerodynamic force production and power requirement were compared with that of the normal hovering whose stroke plane was horizontal.The main results are as following.The major part of the weight-supporting vertical force is produced in the downstroke and it is contributed by both the lift and the drag of the wing,unlike the normal-hovering case in which the lift principle is mainly used to produce the weight supporting force.The mass specific power is 31.71W·kg-1 that is similar to the normal hovering case.Because of the body being horizontal,immediate forward acceleration and roll maneuvering can be made,but no more power is needed.