Hydrodynamic Analysis for High-Head Leaf Gates

By separate analyses of the effects of flow and geometry on the hydraulic downpull on gates, a basis is provided for the generalization of experimental downpull data. Although applied only to high-head leaf gates, the analyses also should prove adaptable to other types of closure devices. In a simple downpull equation, the flow effects are considered in terms of the discharge, for which an expression is derived by the one-dimensional method of analysis. The effects of the boundary geometry are considered with the aid of form coefficients and are evaluated for various common lip shapes from two-dimensional air-tunnel experiments. The susceptibility of the lip shapes to unstable flow separation and the development of subatmospheric pressures is examined. The test results contribute to generalized design information that permits the prediction of downpull, as well as the synthesis of the most favorable composite form of conduit and gate. Bibliographic material on the hydraulics of high-head gates is included.