Experimental investigation on interaction between extreme waves and a submerged barrier

Abstract

We present experimental results of a group of focused waves propagating over a submerged barrier positioned in various locations on the bottom of a flume. The study investigates the effect of the relative distance between the fixed focusing position and different barrier installation positions on the characteristics of the wave group. The surface elevation and skewness are observed to approach a crest just on top of the barrier's rear. It can be also suggested that the presence of the barrier may affect the evolution of the wave group for approximately two times of the barrier length, as indicated by the frequency component distribution. In the time domain, a small tail with mildly higher energy is generally observed when the gauge is fixed at the front surface of the barrier. It suggests that long waves at lower frequencies propagate at higher speeds, while short waves at higher frequencies are intercepted due to the barrier.