Hydraulics of Closed Conduit Spillways Part X. The Hood Inlet

Comprehensive experiments on the hood inlet for closed conduit spillways are reported. The capacity and performance of the spillway for variations of the hood inlet length, the conduit slope, the wall thickness and the approach conditions are described. The great effect of vortices on the spillway capacity is shown and anti-vortex devices are developed. Scour in the vicinity of the hood inlet is determined for various sizes of stone and equations for the scour hole dimensions are presented. A few special inlets were tested, the effect of rounding the entering edge being the principal variation.