Abstract:

ESDU 81034 provides data for evaluating the forces, moments and pressure distributions on a thin aerofoil (strictly a flat plate) oscillating in heave and in pitch and with the oscillation of a trailing-edge control, with its hinge line at 0.8 of the aerofoil chord, in subsonic flow. The airforce coefficients are tabulated over frequency parameter and Mach number ranges of 0.05 to 2 and 0 to 0.9 respectively. Examples of the chordwise load distribution are presented graphically to show the effect of Mach number and frequency parameter. An Appendix provides a set of conversion equations to obtain flutter derivatives from the airforce coefficients and these have been used to derive tables of flutter derivatives. A second Appendix demonstrates the use of two-dimensional strip theory to incorporate flutter derivatives into three-dimensional flutter equations. The data were obtained from a computer program, which embodies a method for evaluating the forces, moments and pressure distributions on a thin two-dimensional aerofoil oscillating harmonically with very small amplitude in subsonic flow.