中文摘要：

利用不同格式模拟扰动波在平板边界层中的传播，考察了格式对T-S波传播过程计算结果的影响。研究了不同计算格式对自由剪切层扰动波增长的影响，结果表明：对于二维扰动波模型，采用二阶精度格式，扰动波在平板边界层中只能出现衰减的结果；在自由剪切层中，虽然能模拟出扰动波在传播过程中幅值的增长，但却在相当长的计算范围内看不见三维波的出现。但对于同样的扰动模型，如果采用高精度格式，在边界层中能出现增长的T-S波，并与线性理论非常吻合；在自由剪切层中，扰动波不仅迅速增长，并能在不很长的距离内，明显的看到三维波的出现，并激发出了三维结构。

英文摘要：

The influence of the different finite difference schemes on the transmission of T-S waves in flat plate boundary layers and free shear flow was studied. The results show that if 2nd order scheme is used,the T-S waves always decay in the flat plate boundary layer. Although the T-S wave grows in the free shear flow,no three dimensional structures appear. If high order scheme is used,the T-S wave grows in the plate boundary layer. The results obtained by DNS agree well with linear stability theory. In the free shear layer,not only the T-S wave grows quickly in the free shear flow, but also three dimensional waves appears evidently and three dimensional structures are excited.