吸气式高超声速飞行器耦合运动数值模拟

为了研究吸气式高超声速飞行器在俯仰/滚转两自由度耦合运动下的动稳定性问题，基于气动/运动耦合数值模拟方法并结合理论分析，针对一种类似SR-72构型的吸气式高超声速飞行器开展了进气道通流状态下强迫俯仰/自由滚转耦合运动数值模拟研究。结果表明:强迫俯仰/自由滚转耦合运动下，滚转通道的动力学方程可以简化为有阻尼的Mathieu方程形式，并且可以求得稳定性边界。理论分析表明:滚转通道的动稳定性与俯仰振荡角频率相关，在飞行器滚转振荡固有角频率附近存在2个临界角频率，当俯仰振荡角频率位于2个临界角频率之间时，滚转通道是动不稳定的。在俯仰振荡振幅较小时，数值模拟结果与理论符合较好，但实际的临界角频率与理论分析求解的值有一定偏差；数值模拟结果表明随着俯仰振荡振幅增大，导致滚转发散的角频率范围变得更宽，且向更高频率偏移。 

Numerical simulation of coupling motion of an air-breathing hypersonic vehicle

In order to study the dynamic stability of an air-breathing hypersonic vehicle under coupling motion of pitch/roll, based on the aerodynamic/kinematic coupling numerical simulation method and theoretical analysis, the numerical simulation of forced pitch/free roll coupling motion of an air-breathing hypersonic vehicle with an inlet similar to the SR-72 configuration was carried out. The results show that the dynamic equation of the roll channel under the coupled motion of forced pitch/free roll motion can be simplified to the damped Mathieu equation, and the stability boundary can be obtained. Theoretical analysis shows that the dynamic stability of the roll channel is related to the angular frequency of pitch oscillation. There are two critical angular frequencies around the natural angular frequency of the aircraft roll oscillation. When the angular frequency of pitch oscillation is between the two critical angular frequencies, the roll channel is dynamically unstable. When the pitch amplitude is small, the numerical simulation results are in good agreement with the theory, but there is a certain deviation between the actual critical angle frequency and the theoretical value. The numerical simulation results show that with the increase of pitch amplitude, the angular frequency range resulting in rolling divergence becomes wider and shifts to higher frequencies.