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A Computational Study for Biological Flapping Wing Flight
生物振翼飛行之數值計算研究
摘要
本文基於將整片翼面區分成許多粗細條狀機翼之理念，建立起一個可模擬計算振動翼之暫態空氣動力模式。這個模式可用來將一整片振動翼視成一組互相串連在一起的機翼並計算其平均昇力、推力及所需之功。此外，本文亦針對可能的振翼飛行條件，發展出一個最佳化方法以計算最大之推進效率。針對大型飛行生物。古代之翼龍以及小型飛行生物，烏鴉、海鷗、鴿子等四種案例所產生之渦流型態進行計算，以分析這些生物飛行器之空氣動力效能。結果發現所研究之四種生物其推進效率在65-75%间；然而昇力及推力親生物之重量、振翼頻率和飛行速度而定。維持飛行（昇力大於體重）所需之振翼扭力在各不同生物間亦有所不同，通常是隨著生物體積之變大而變小。
並列摘要
A computational model for unsteady aerodynamics of a flapping wing has been developed based on the strip theory, which makes use of the concept of dividing the wing into a number of thin strips. This enables us to study the wing as a set of airfoi1s next to one another by assuming no crossflow between them. Wing kinematics including normal and chordwise force calculations was considered to calculate average lift, thrust, power requirements and propulsive efficiency for a flapping wing in flight. In addition, an optimization procedure was developed for obtaining maximum propulsive efficiency within the range of possible flying conditions. Computations were performed on a mechanical flying Pterosaur replica as wel1 as smal1er biological species including the Corvus monedula, Larus canus and Columba livia, which makes use of the vortex gaits. The effect of aerodynarmic parameters on the performance of these biological flight vehicles was studied. It was found that the propulsive efficiency of al1 species considered were around 65-75% whereas the lift and thrust varied largely depending on the weight, flapping frequency and flight speed of the species. The range of dynamic twist for sustainable flying conditions (Lift＞Weight) also varied for different species, becoming smal1er as the size of a bird increases.