说明：  用谱方法计算流体力学一些流动现象的整体稳定性,针对EMD方法的不足,FIR 底通和带通滤波器和IIR 底通和带通滤波器。
( Spectral methods of computational fluid dynamics flow of some of the overall stability of the phenomenon, For lack of EMD, Bottom-pass and band-pass FIR and IIR filter bottom pass and band-pass filter.)