Basic characters about bore

The basic characteristics of bore and dambreak wave are analyzed. Although the flux mass and momentum of flow remain conservational when a flow goes through a bore, there is certain loss of mechanical energy, so SaintVenant equations cannot be used to describe the flow near the bore. Microcosmically, if dissipation and dispersion are taken into account, which are caused by component of vertical velocity and nonuniformity of horizontal velocity, the attenuated high frequency wave occurs in the back of bore, and wave steepness increases rapidly, causing water surface unstable, and then forming roller. The analysis shows that Froude number is the ratio of dispersion to dissipation, which controls the local shape of bore, and the results are close to the experimental data. Because of the complexity of configuration of river, the source item of controlling equations should be handled when numerical simulation executed, in order to further understand the characterstics of bore.