基于近似边界条件的三维机翼气动弹性数值模拟研究

Faster but Still Accurate Calculation of Wing Flutter Using Unsteady Transonic Euler Equations with Approximate Boundary Conditions

物面边界条件采用一阶近似边界条件,计算网格采用静止的笛卡尔网格;通过求解Euler方程,得到三维机翼的非定常气动力,耦合机翼运动方程进行气动弹性的计算;流场和结构之间的数据通过无限平板样条法(IPS)进行交换。使用文中方法计算了三维气动弹性标准模型AGARD 445.6机翼的颤振边界,计算结果与实验结果吻合,表明该方法可以准确高效地求解三维机翼的气动弹性问题。

Aim. Our review of past researches at the beginning of this paper shows, we believe, that faster but still accurate calculation is much needed. Our faster calculation possesses three distinct advantages： （1） easy generation of grid, （2） no moving of grid, （3） less computing time and memory needed. The unsteady Euler flow solver is based on the finite volume method. Wall boundary conditions are implemented on non-moving mean wall positions; the first-order approximate boundary conditions are used in Euler equations on stationary Cartesian grids. For the structural displacements, a modal approach is applied. The solution of the flow and the structural dynamics are in time domain. IPS （infinite plate spline ） method is used for data interaction between CFD （computational fluid dynamics） and CSD （computational structural dynamics）. A flutter analysis of the AGARD 445.6 wing is performed. The calculated flutter speed boundary and flutter frequency boundary, given respectively in Fig. 2 and Fig. 3 of the full paper, are in good agreement with experimental data and known calculated results.