Periodic Supersonic Motions of a Thin Wing of Finite Span

Citation

Li, Ting-Yi (1950) Periodic Supersonic Motions of a Thin Wing of Finite Span. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/VZX8-E374. https://resolver.caltech.edu/CaltechETD:etd-03172009-110456

Abstract

The present paper supplies some general theorems with which periodic supersonic motions of a thin wing of fairly general planform may be analyzed to yield valuable three-dimensional results. It is shown that the method developed by Evvard (Refs. 1,2) for treating the steady supersonic motion of a thin wing with subsonic leading or side edges is valid for an oscillating wing of similar planform. Illustrations of the application of these general theorems are furnished by a careful study of several types of periodic oscillations of a rectangular wing. The present report includes a complete analysis for the case of plunging oscillations. Important steps have also been taken towards solution of the cases of pitching and rolling oscillations. The essential results are presented in a number of vector diagrams giving the magnitudes and phase angles of the lift and moment. Computations are made for several aspect ratios at two Mach numbers (M=10/7,2) when the reduced frequency (k) ranges from 0 to 2.0. It is found that the lift and moment vectors acting on a rectangular wing with supersonic plunging oscillations have positive phase angles within certain ranges of Mach numbers and aspect ratios, while the corresponding vectors acting on a wing of infinite span with the same kind of motion have negative phase angles for every Mach number. This new discovery indicates strongly the necessity of revising present day wing flutter calculations.

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