Study of the Roll Orientation Effects on Vortex Asymmetry on a Conical Forebody at High Angles of Incidence

摘要

Vortex asymmetry on conical forebodies at high angles of incidence results in large side force and yawing moments. Although the problem is well known and a number of flow control methods have been exploited, the nature of the instabilities causing vortex asymmetry and its variation with the roll orientation is not well understood. Experiments involving force and moment measurements and Particle Image Velocimetry on a conical forebody were performed at a Reynolds number of 0.22 million at various angles of incidence and roll orientations. Simulations involving a high-fidelity Navier-Stokes solver was performed near the tip region to better understand the flow physics. The results confirm the role of micro-imperfections near the tip region of conical forebody in developing vortex asymmetry and show that both the side force magnitude and the direction is very sensitive to roll orientation at high angles of attack.