Experimental study of the dam-break waves in triangular channels with a sloped wet bed

Abstract

There has been little study on the impact of bottom slope on dam break wave propagating along a triangular wet channel. In this study, laboratory experiments are conducted in a large-scale triangular laboratory flume, covering a range of bed slope and rations of upstream over downstream water depth. Water surface and stage hydrograph wave height are collected using the non-intrusive measurement methods, which are used to obtain wave characteristics. Results show that for dry bed, the wavefront celerity increases with the increase of the slope; while for a wet bed, the wavefront celerity decreases as the slope increases and the decrease rate is significantly reduced. Moreover, the wavefront celerity decreases with the increase of water depth ratio. The maximum wave height at each measurement location decreases with the increase of water depth ratio. According to the arrival of the maximum wave height, the dam-break wave can be classified into two modes, namely Type A in which wave height gradually rises to the maximum when flow reaches and Type B in which the maximum wave height appears at the beginning of the dam failure. This study is useful for in-depth understanding of the dam-break wave evolution in sloping triangular wet rivers.