Vortex breakdown characteristics of flying wing aircraft based on jet flow control

Abstract

To delay the position of vortex breakdown and increase the lift characteristics of the flying wing aircraft, the vortex breakdown characteristics of a flying wing aircraft under jet flow control were studied based on numerical simulation. The design idea of jet excitation selection based on the natural helical mode frequency of the aircraft is proposed. The flow fields and frequency spectrum characteristics of aircraft before and after applying steady and unsteady excitation are analyzed. The results show that under the same jet momentum coefficient, the control method of unsteady excitation has more advantages. The control effect of excitation frequency in the range of helical mode instability frequency is generally better than that outside the helical mode. When the excitation frequency is consistent with the peak value of the main frequency of the upstream helical mode, optimal control effect is obtained, which has the most supplement to the axial velocity and obvious suppression effect on the separation zone. Moreover, periodic energy injection can enhance the peak value characteristics of the main frequency, make the frequency range of the downstream flow field develop toward high frequency, and accelerate the rotation of the flow field after the vortex breakdown.