基于DMD方法的飞翼小振幅振荡频率对动导数特性影响机理研究

飞翼布局是实现新一代战斗机隐身、气动一体化设计的理想选择。在飞行器稳定性设计中，动导数是飞行器动稳定性的重要表征参数。在风洞试验中发现，飞翼标模在大攻角下俯仰振荡频率对动导数影响很大，严重时甚至会出现动导数变号的现象，这将极大影响对飞翼动稳定性的评估。针对这种现象，拟采用延迟脱体涡模拟方法（DDES）及动力学模态分解方法（DMD），将大攻角下飞翼标模复杂流动降阶为若干典型流动的线性组合，通过模拟飞翼标模在不同频率下小振幅振荡运动，获取大攻角分离流动模态的响应特性，建立微观结果（流动模态）与宏观性能指标（动导数）的联系，揭示飞翼振荡频率对动稳定性影响机理，为我国飞翼布局飞行器稳定性设计提供理论指导。

The flying-wing configuration is one of the ideal choices for the integration design of stealth and aerodynamic of the new generation fighters. In the aerodynamic stability design of aircraft, the dynamic derivative is an important parameter to characterize the dynamic stability of aircraft. In the wind tunnel test, it is found that the oscillation frequency of the flying-wing model has a great influence on the dynamic derivatives at high angle of attack, and in severe cases, the dynamic derivatives may even change sign, which will greatly affect the evaluation of the dynamic stability of the flying-wing. The Delay Detached Eddy Simulation (DDES) and Dynamic Mode Decomposition (DMD) are adopted to simplify complex separated flow at high angle of attack to some linear combinations of typical flows. By simulating the small amplitude oscillation motion of the flying-wing at different frequencies, the response characteristics of the leeward separation flow modal are obtained, and the relationship between the microscopic characteristics (flow modal) and the macroscopic performance indicators (dynamic derivatives) is established, and the influence mechanism of the oscillation frequency on the dynamic stability characteristics can be explored. The research results can provide theoretical guidance for the stability design of the new generation of fighters with flying-wing configuration.