Experimental investigation of propagation and run-up of rockslide- generated impulse waves in a curved mountain reservoir

Propagation and run-up of impulse waves generated by rockslides in curved channels are investigated by carrying out three-dimensional laboratory tests. The objective is to study the effects of sharply curved river bends on the wave transmission and run-up features of breaking waves in a 90° channel bend. The slide characteristics were measured at impact by high speed cameras and the time series of the resulting changes in water surface elevation were measured by 26 wave probes along radial and angular direction. The experimental results indicate that in the straight channel the attenuation rate of radially propagating waves in different angular directions remains the same. As waves propagate to the channel bend, they are fully transmitted with little backward reflection, but the transmitted leading wave amplitude will no longer preserve an immobile attenuation law but will tilt outward against the outside bank with the centrifugal force. Therefore, the attenuation rate of wave amplitude in the curved channel is not only related to the propagation distance, but also related to the propagation direction. In addition, the existence of the bend significantly influences the wave run-up at the opposing hillslope. This paper demonstrates that the water jet-flow generated after wave breaking on the outer bank of channel bends causes the opposing hillslope maximum run-up to be greatly increased compared to the straight channel case. A predictive equation for breaking waves at the bend is derived and a method to predict the maximum run-up along the hillslope opposed to the wave generation is provided. Furthermore, characterizing the characteristics of the run-up along the coasts through experimental measurements provided valuable data about how such topographic feature contribute to the design of coastal structures.