基于阶跃响应的飞行器单独静、动导数数值求解方法

基于阶跃响应方法，结合刚性动网格技术，对飞行器的单独静、动导数的精细化数值计算进行了研究.以纵向为例，通过给物面施加恒定附加攻角，求解得到阶跃响应运动过程的非定常气动力，求导得到静导数.同样给物面施加恒定的俯仰角速度，并同时强迫物面平动以抵消俯仰转动产生的附加攻角影响，可由非定常气动力求导得到动导数值.分别利用NACA0012翼型和三维SACCON飞翼无人机进行了计算验证，各攻角下的静、动导数值与文献、试验结果吻合得很好，最大误差不超过5%.结论表明:基于阶跃响应的单独静、动导数直接模拟方法计算耗时仅为传统强迫振动方法的21%，效率相对较高，且可推广到横航向的动导数计算，为飞行器的稳定性研究提供参考. 

Calculating single static and dynamic derivatives of aircraft with step response method

Based on step response method and rigid moving mesh techniques, the fine single static and dynamic derivatives of aircraft were simulated. Longitudinal derivatives were taken as examples to represent these methods. Firstly a constant additional angle of attack was applied on the aircraft, and the unsteady aerodynamic force was calculated during the step response process, then the static derivative can be identified from the derivation of aerodynamic force; similar to static derivative, a constant pitching angular velocity was used to force the aircraft pitching around the reference point, and also a translate speed should be considered at the same time to eliminate the effect of additional angle of attack generated from the pitching angular velocity. NACA0012 airfoil and SACCON fly wing unmanned combat aerial vehicle were used to test the methods, both the static and dynamic derivatives of the two configurations agreed well with the reference and wind tunnel test results,with the maximum error no more than 5%. The research shows that the computational time of direct single static and dynamic derivatives simulation methods based on step response is nearly 21% of the of traditional oscillation method, with relatively higher effectiveness; this can be used in analysis of lateral and directional derivatives as well as longitudinal ones, providing technical reference for aircraft stability.