基于谐振舵面的跨声速抖振抑制探究

跨声速抖振引起的非定常脉动载荷会造成飞行器结构疲劳甚至引发飞行事故,所以跨声速抖振的控制研究逐渐成为航空领域的热点。采用基于Spalart-Allmaras(S-A)湍流模型的非定常雷诺平均方程开展了基于谐振舵面的跨声速抖振抑制研究。首先验证静止NACA0012翼型的抖振边界和频率特性,然后分别从舵偏平衡位置、舵偏幅值、频率以及相角等角度研究了谐振舵面的控制效果。舵偏平衡位置等效于减小了翼型的有效迎角;幅值和频率对抖振抑制效果影响较大,当舵面振荡频率与抖振频率接近时发生共振现象;相角对控制效果有一定影响,在270°相角附近,升力系数幅值减小了60%。在合适的舵偏幅值、频率以及相角组合下,谐振舵面有可能成为跨声速抖振的有效开环控制策略。

Study on transonic buffet suppression with flapping rudder

Structural fatigue and flight accidents may be caused by the oscillating loads induced by buffet in transonic flight, so transonic buffet control is becoming a hot topic in the field of aviation. An investigation based on unsteady Reynolds-averaged Navier-Stokes equations and Spalart-Allmaras(S-A) turbulence model is presented to study the suppression of resonant rudder on the transonic buffet loads in this paper. First, the buffet onset and frequency characteristics for a stationary NACA0012 airfoil are verified with the experimental data. And then, the validation of the resonant rudder are studied from the variables of initial rudder angle, amplitude, frequency and phase angle. The initial rudder angle can reduce the actual angle of attack of the airfoil by the down effect. The amplitude and frequency are main parameters. In the case of rudder with a frequency very close to the buffet frequency, resonance occurs and the amplitudes of the lift and moment coefficients increase rapidly. The phase angle is also an important factor. Lift coefficient has an decrease of about 60% at phase angle towards 270°. Therefore, resonant rudder may be a feasible open-loop strategy to suppress buffet loads with an appropriate and accessible combination of amplitude, frequency and phase angle.