大厚度翼型弹性振动中的分叉现象分析

Bifurcation analysis of the vibrating airfoils with large thickness at high incidences

基于SST两方程湍流模型,求解了雷诺平均Navier-Stokes方程获得非定常气动力,耦合翼型弹性振动方程,在时间域内模拟了大厚度对称翼型的振动过程,探讨了大迎角下大厚度翼型的流场和气动弹性的分叉现象。研究发现,在百万雷诺数条件下,厚度大于20%的对称翼型在一定大迎角范围内,会出现气动弹性振动过程的分叉现象,通过跟踪流场的变化发现,引起翼型振动分叉的原因在于翼型分离涡平衡态的转化。

The unsteady flows are computed based on the Reynolds-Averaged Navier-Stokes equations with SST turbulence model.Coupled with the equations of motion for elastic supported airfoils,the aeroelastic responses of airfoils with large thickness are simulated in time domain.Especially,the bifurcation responses of thick airfoils at certain range incidences are comprehensively investigated.Results indicate that the aeroelastic response at high incidence is significantly influenced by the separation flow.For the given Reynolds numbers and structure parameters considered in paper,the bifurcation phenomena appear in the aeroelastic responses of the airfoils with thickness larger than 20%.By analyzing the unsteady flow fields,it is found that transition of the equilibrium of separation flow results in the bifurcation responses.