Experimental study on sandy beach profile changes by tsunami waves under effect of submerged breakwater

A series of two-dimensional experiments were performed to investigate whether or not submerged breakwater could effectively reduce the tsunami scouring on the sandy beach.The incident wave was solitary wave.The different location of submerged breakwater and depth of submergence were considered respectively in this study.The comparative study was also carried out to make a comparison with sandy beach profile changes by tsunami waves without submerged breakwater.The free surface elevations,flow velocity,processes of wave uprush and back wash,the change of cross-shore beach profile were measured and recorded.The experimental result showed that the submerged breakwater could not effectively reduce the tsunami scouring on the sandy beach and could influence the height and position of deposition sand bar.At same time,there was a deposition on the off-shore side of submerged breakwater and a scouring on the onshore side.The effect of reducing the deposition sand bar could be obvious when the submerged breakwater located in the hydraulic jump took place.The maximum local tsunami scour depth could decrease,as depth of submergence kept and offshore distance of submerged breakwater decreased.