Blowing Effects on the Separated Flow over a Moderately Swept Missile Fin

Abstract

This aim of this numerical study is to control the separated flow over a generic missile fin characterized by a sweep angle of 50 deg and a sharp leading edge. The flow without control separates at the leading edge and the fin is stalled. To control the flow separation, a blowing slot is placed all along the fin leading edge, and both continuous and pulsed blowing are applied. The nondimensional frequencies F + based on the freestream velocity and the root chord of the fin are equal to 1, 1.5, 3, 6, and 10. Applying continuous blowing results in a larger reverse-flow region than in the reference case. As a consequence, the aerodynamic performance of the fin is deteriorated. Conversely, using pulsed blowing tends to decrease the pressure over the fin and the extent of the reverse-flow region. The performance of the fin is then enhanced, particularly for a pulsing frequency equal to that of natural vortex-shedding (F + = 1.5). Finally, the last part of the paper discusses the effects of the suction phase by comparing synthetic-jet actuation and pulsed blowing at the optimal frequency.