SUPERCRITICAL BEND FLOW

Supercritical dow in chute bends is considered both theoretically and experimentally. The conventional approach is found to apply to small r elative curvature only. The knowledge is extended to large bend number s, and a design procedure is presented. Supercritical bend flow in the smooth horizontal and rectangular channel is considered. It is found that the maximum standing wave heights are influenced by the bend numb er, that is, the approach Froude number times the square root of the a verage relative curvature. Current models are demonstrated to apply fo r relatively small bend numbers. For modest and large bend numbers, ho wever, the flow pattern is modified. Besides the extreme wave lengths, the generalized surface profiles along either bend wall, the typical velocity fields, and the separation mechanism are experimentally studi ed. Also, a model for separated bend how is developed. Photographs are presented that illustrate the uneven distribution of separated bend h ow in regard to the cross-sectional area. This study allows a simple a nd straightforward design of chute bends.