Flow Fields in Lower Lock Approaches Induced by Hydro‐Plant Releases

Abstract

Flow fields and navigation conditions induced by hydro‐plant releases into lower lock approaches are investigated for hydro plants in typical riverine lock‐and‐dam installations and a wide range of flow conditions. Both steady‐state and transient tests are carried out. The effects of currents and surges on tows are determined by operating a scaled barge tow. Acquisition of flow field and navigation test data for a large combination of geometries and flow conditions is feasible using an image‐processing system. The size and upstream velocity along the lower guide lock wall of an eddy generated during steady state, and the heights of the surges developed during powerhouse start‐ups and shutdowns are the most critical flow parameters for evaluation of navigation impacts. Relationships are obtained for the prediction of these critical parameters in terms of geometric and flow variables. Based on the navigation tests, criteria for acceptable navigation conditions were developed. Amelioration of adverse navigation effects is achieved by installing flow‐training structures; a relationship is presented for the preliminary design of these structures.