基于气/固耦合非定常流动的叶栅颤振分析

Cascade flutter investigation based on flow-structure coupling unsteady flow

采用二维N-S方程/结构振动方程组耦合数值方法,分析计算了二维非定常气动力强迫振动条件下振动能量及气动力对叶栅所做的功,分别根据振动能量和气动力做功分析了叶栅的颤振特性。NACA0012和PROF叶栅在不同折合频率下气动参数随时间的变化表明,折合频率是影响叶栅颤振的重要因素。气固耦合方法得到的NA-CA0012叶栅颤振折合频率比非耦合的结果高,而对PROF叶栅则相反。这表明叶栅结构动力参数对其发生颤振时的折合频率影响很大且很复杂,要准确预测颤振应该考虑叶栅结构动力与气动力的耦合因素。

The vibration energy and aerodynamic work of unsteady aerodynamic force on cascade in forced vibration were investigated using numerical solution of 2-D Navier-Stokes/structure coupled equations, and the flutter characteristic was analyzed according to the vibration energy and aerodynamic work. The variation of aerodynamic parameters of cascade NACA0012 and PROF under different reduced frequency shows that the reduced frequency is an important factor that influences the flutter, The reduced flutter frequency of cascade NACA0012 obtained from flow/structure coupling analysis is higher than that from uncoupling analysis, but it is opposite for cascade PROF. This shows that the structure dynamic parameters of the cascade have large influence on the reduced flutter frequency. Thus structure dynamic factors must be taken into account of flutter analysis.