圆弧翼型跨声速流动的动态模态分析

跨声速翼型的激波周期性自激振荡会给机翼结构带来附加的脉动载荷，从而加剧飞行器表面结构的疲劳损伤。使用动态模态分解（DMD）方法研究了跨声速下绕厚度18%的对称双圆弧翼型的压力脉动场，分析了DMD提取的各阶主模态的频率特征、压力脉动的空间分布以及压力脉动随激波振荡的时间演化过程，并使用DMD模态进行流场重构。结果表明，DMD方法能准确捕捉流场各特征频率的模态，第1阶模态是激波抖振的主频，在激波的自激振荡过程中占主导作用，前7阶模态重构的流场损失函数降低至4%以内，误差主要分布于激波间断处。 

Dynamic modal analysis of circular-arc airfoil transonic flow

The periodic self-oscillation of the shock wave of the transonic airfoil will bring additional oscillating loads to the wing structure, thereby aggravating the fatigue damage of the aircraft structure. The dynamic mode decomposition (DMD) method is used to study the pressure fluctuation field of a symmetric circular-arc airfoil with a thickness of 18% around the transonic speed. The frequency characteristics of the main modes of DMD, the spatial distribution of pressure fluctuation and the time evolution of pressure fluctuation with shock wave motion are analyzed, and then DMD mode are used for flow field reconstruction. The results show that the DMD method can accurately capture the mode of each characteristic frequency of the flow field, and the first-order mode is the dominant frequency of the buffeting of the shock wave, which plays a dominant role in the self-oscillation process of the shock wave. The flow field loss function of the first seven modes is reduced within 4%, and the error is mainly distributed in the shock wave discontinuity area.