Experimental study on the dam-break hydrographs at the gate location

Abstract

When studying the dam-break flow phenomenon, the basic hydrodynamic features of the dam-break flow at the gate location should be verified primarily. In this study, laboratory experiments were performed in a rectangular and horizontal flume with the same initial water head setting on the dry and wet downstream bed conditions. Water surface elevation was extracted through image analysis and validated by comparing with the data measured using a wave gauge. Temporal variation of the water surface elevation at the gate location, quantified in terms of high-speed video recorded images, can be divided into three stages, the sharp decreasing stage, the relatively steady stage, and the gradually decreasing stage. Applicability of several classic analytical solutions of the dam-break problem at the gate location was validated using present experimental data. Ritter’s solution is effective for the dry bed condition while Stoker’s solution could be applied to the wet bed case, and both are only applicable during the steady stage. Lin’ solution reproduces the gate-site hydrographs well during both the relatively steady and the gradually decreasing stages, especially for the condition under which the down-upstream water depth ratio is smaller than 0.138.