Measurements and calculations of steady and oscillatory pressures on a low aspect ratio model at subsonic and transonic speeds

Abstract

Steady and time-dependent pressures have been measured for oscillatory pitching motion at frequencies of 0, 12, 33 and 70 Hz on a model of the AGARD SMP tailplane at Mach numbers from 0·65 to 1·20. Some wall interference effects at transonic speeds were observed. For attached flows at transonic speeds the time-dependent pressures are in good agreement with predictions according to Garner's semi-empirical theory, as long as the local Mach number upstream of the shock is less than 1·1. For separated flows the semi-empirical theory gives poor predictions, particularly for the imaginary component of the pressure. Flow separation causes large low frequency effects beyond the scope of the predictions.