Rapidly Varied Flow

Abstract

In non-uniform channel flow the longitudinal position of the resulting surface profile is fixed by the hydraulic properties of a particular section in the channel called a control section. In some cases the position is determined by two control sections, one upstream and the other down. The determinate nature of control sections enables the depth of flow there to be found as well as the surface profile to be positioned. In order for the depth to be determined, either a simple relationship must exist there between the depth and the discharge or else the depth must be imposed by external factors and be independent of the flow.