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跨声速抖振现象是由于非定常跨声速流动中激波的自激振荡而引起的结构强迫振荡,这种现象在跨声速飞行器中普遍存在,对飞机的结构强度和疲劳寿命有不利影响。基于模态分解的分析方法是进一步发展抖振控制手段的有效工具。本文通过两类典型模态分析方法(本征正交分解(POD)和动态模态分解(DMD))对OAT15A翼型的跨声速抖振现象进行分析,通过对模态频率、翼面压力分布、流场重构误差等方面的研究,将两种模态分解方法进行对比。发现基于频率特征的DMD方法能够准确捕捉抖振的临界稳定特征和抖振主频的典型模态,同时能够更准确反映流场变量在激波间断附近随时间的变化过程;而POD方法尽管在流场重构时具有较小的总体误差,但对激波附近压强随时间的变化历程拟合较差。
Transonic chattering is a structural forced oscillation induced by the self-excited oscillations of shock waves in unsteady transonic flows, a phenomenon that is common in transonic aircraft and adversely affects the structural strength and fatigue life of the aircraft. The analysis method based on modal decomposition is an effective tool to further develop the chattering control method. In this paper, we analyze the transonic chattering of OAT15A airfoil by two typical modal analysis methods (POD and DMD). By analyzing the modal frequencies, the airfoil pressure distribution , Flow field reconstruction error and other aspects of the study, the two modal decomposition method for comparison. It is found that the DMD method based on frequency characteristics can accurately capture the critical stability characteristics of chattering and the typical mode of chattering dominant frequency and can more accurately reflect the variation of flow field variables with time near the shock discontinuity. The flow field reconstruction has a smaller overall error, but the fitting of the pressure near the shock wave over time is poor.