非线性壁板颤振分析

利用一种改进的计算流体力学与计算结构动力学(CFD/CSD)耦合方法研究了由气动和结构几何非线性引起的壁板颤振问题。在非定常气动力计算中,考虑了通量分裂格式、隐式时间推进方法和几何守恒律;二维和三维壁板的结构几何非线性建模则采用了有限元的协同旋转理论,并利用一种近似能量守恒算法求解结构的非线性响应。流场和结构求解器采用二阶松耦合方法联立求解,并将其应用于壁板在超声速、跨声速和亚声速的颤振计算中。当考虑结构几何非线性和气动非线性时,出现了典型的极限环振荡现象,并对颤振边界和极限环振荡幅度进行了对比分析。

Analysis of nonlinear panel flutter

Nonlinear panel flutter caused by the interaction between nonlinear fluid and geometrically nonlinear structure is studied by an improved computational fluid dynamics and computatienal structural dynamics (CFD/CSD) coupled program. A flux splitting scheme combined with implicit time marching technology and geometric conservation law is utilized to solve unsteady aerodynamic pressure; the finite element corotational theory is applied to modeling the geometric nonlinear two-dimensional and three-dimensional panels, and an approximate energy conservation algorithm is developed to obtain nonlinear structure response. The two solvers are connected by a second-order loosely coupled method and applied to the solution of panel flutter problems for supersonic, transonic and subsonic Mach numbers. A representative limited cycle oscillation appears when geometric nonlinearity and aerodynamic nonlinearity are considered. The flutter boundary and amplitude of limit cycle oscillation are discussed.