Fourier伪谱方法在不可压缩平板边界层研究中的应用

以三维不可压缩平板边界层为研究对象,扰动形式N-S方程为控制方程,从空间模式的角度,直接数值模拟了三维不稳定T-S波传播的过程.时间离散采用三阶精度混合显隐分裂格式,空间离散则结合Fourier伪谱方法及高精度紧致有限差分逼近,法向采用非等间距网格坐标变换,出口边界条件采用嵌边函数法,程序采用MPI(Message passing interface)并行方法编写.实例验证,该方法计算结果与流动稳定性分析的结果一致. 

Application of fourier pseudo-spectral method in the incompressible boundary layer on a flat plate

Three-dimensional incompressible boundary layer on a flat plate was studied where disturbance N-S equation was taken as governing equation.The evolution of three-dimensional instability T-S wave was simulated by spatial DNS(direct numerical simulation) in which third-order precision mixed explicit-implicit scheme was employed for temporal discretization while a method combining Fourier pseudo-spectral method with high precision compact finite difference was implemented for spatial discretization.A coordinate transform of nonuniform meshes was applied in normal direction,fringe method was adopted as exit boundary condition and MPI method was used in programming.Through a simple case,the results obtained by this method were tested to be in consistence with the ones obtained with stability theory.