关键词: 动导数, 强迫振动, 动稳定性, 当地流活塞理论, 高超声速, 计算流体力学

Abstract: In the early stage of aircraft design, it is necessary to predict the dynamic stability derivatives under a large number of operating conditions. An extremely efficient prediction technique of dynamic stability derivatives for high-speed flight vehicles is developed in this paper. Firstly, the unsteady aerodynamics of high-speed flight vehicles can be divided into non-disturbance aerodynamic component and disturbance aerodynamic component, based on the local piston theory; Secondly, the local surface inclination method, together with the isentropic flow relation after a shock wave are employed to solve the surface flow veriables, and then the unsteady aerodynamic forces are calculated by combining the unsteady motion; finally, the dynamic derivatives are extracted and identified from unsteady aerodynamic forces with by the undetermined coefficient method. Our method eliminates the time-consuming of traditional CFD method, which is dependent and coupled with numerical simulation flow field variables. Typical test cases indicate that our method can predict the trend of dynamic derivatives well under both supersonic and hypersonic conditions. At last, ourmethod is successfully applied to dynamic derivatives prediction of flight vehicles with complex shape, and the error sources with CFD method are discussed. The effieicnt dynamic derivatives prediction technique in this paper can be used to screen layout of high-speed flight in conceptual design stage.

Key words: dynamic derivatives, forced vibration motion, dynammic stability, local piston theory, hypersonics, computational fluid dynamics