Short wave lengths correspond with high frequencies,and long wave lengths to low frequencies. 短波波长和高频相对应，长波波长与低频相对应。
As a qualitative analysis,finite element method gets a more satisfactory result in describing the propagation of the long wave of open channel unconstant flow. 作为一种定性分析，有限单元法对描述明渠非恒定流长波的传播给出了满意的结果。
