Scrutinization of Flow in the Immediate Vicinity of a Brink in a Tilting Flume

The flow characteristics of the subcritical and supercritical flows over an unconfined free overfall in a rectangular channel are presented with experimental data available in the literature. The experimental observations cover a wide range of flow rate on mild, steep and adverse slopes. The dependence of the ratio of the brink depth to the critical depth according to several flow parameters is examined. The relation between the flow rate and the brink depth ratio is both explicitly and implicitly demonstrated. The location of the critical depth for subcritical flows upstream of the brink is also investigated. It is concluded that the location of the critical depth for subcritical flows depends on the Froude number, the channel bed slope and the Manning roughness coefficient. Furthermore, it is observed that there is a significant similarity of the water surface profiles in the immediate upstream vicinity of the brink of the subcritical and supercritical flows.