The Effect of Span-Wise Variations in Amplitude on the Thrust-Generating Performance of a Flapping Thin Wing

Abstract

Flapping movements of wings have been analysed in the past mainly by a strip-wise two-dimensional procedure. This is valid providing the length scale for the span-wise variations far exceeds the chord. If, on the other hand, the span-wise length scale is comparable with the chord, one must modify the two-dimensional flow at each section. The analysis presented here is for a wing of infinite span, but with an assumed sinusoidal variation of flow quantities with respect to the span-wise coordinate. A numerical procedure is developed for solving a singular integral equation for the instantaneous loading on the wing, and results presented for the mean thrust and efficiency of a heaving wing.