Previous studies have shown that high-frequency(HF)waves,low-frequency(LF)waves and wave set-up coexist on shallow coral reef-flat and jointly contribute to potential floods and subsequent damages of infrastructures a...Previous studies have shown that high-frequency(HF)waves,low-frequency(LF)waves and wave set-up coexist on shallow coral reef-flat and jointly contribute to potential floods and subsequent damages of infrastructures and islands on it.To better understand the reef-flat wave dynamics with incident waves and still water level,a wave-flume experiment was performed based on an idealized platform reef composed of a steep reef-face(1:4),a relatively mild reef-rim(1:14)and a horizontal reef-flat.Also,the non-hydrostatic phase-resolving model SWASH was validated against the experiment and then applied to further numerically investigate the effects of reef-rim topographic features on the reef-flat wave motions.The results show that incident waves of a larger wave height and a longer wave period can generate larger LF waves and wave set-up,thereby inducing greater HF waves on the reef-flat.Higher still water level can lead to larger HF waves but result in smaller wave set-up.In contrast to HF waves and wave set-up,LF waves are minimally affected by the still water level.A rim of milder slope and larger edge depth will induce smaller HF and LF waves and set-up on the reef-flat,and thus provide better protection for the reef-flat region.Furthermore,on the reef-flat,the ratio of HF significant wave height to water depth H_(s_h)/(h_(r)+η^(-))is approximately constant;the dimensionless LF significant wave height Hs_l/H_(s0) and the dimensionless wave set-upη^(-)/[T_(p)(gH_(s0))1/2]can be related to the inverse wave steepness parameter gT_(p)^(2)/H_(s0) and the relative reef-flat submergence(h_(r)+η^(-))/H_(s0) respectively.展开更多
基金supported by the Fundamental Research Funds for the Central Universities(Grant No.2018B13314)the Science and Technology Project on Transportation Construction(Grant No.2015328521280).
文摘Previous studies have shown that high-frequency(HF)waves,low-frequency(LF)waves and wave set-up coexist on shallow coral reef-flat and jointly contribute to potential floods and subsequent damages of infrastructures and islands on it.To better understand the reef-flat wave dynamics with incident waves and still water level,a wave-flume experiment was performed based on an idealized platform reef composed of a steep reef-face(1:4),a relatively mild reef-rim(1:14)and a horizontal reef-flat.Also,the non-hydrostatic phase-resolving model SWASH was validated against the experiment and then applied to further numerically investigate the effects of reef-rim topographic features on the reef-flat wave motions.The results show that incident waves of a larger wave height and a longer wave period can generate larger LF waves and wave set-up,thereby inducing greater HF waves on the reef-flat.Higher still water level can lead to larger HF waves but result in smaller wave set-up.In contrast to HF waves and wave set-up,LF waves are minimally affected by the still water level.A rim of milder slope and larger edge depth will induce smaller HF and LF waves and set-up on the reef-flat,and thus provide better protection for the reef-flat region.Furthermore,on the reef-flat,the ratio of HF significant wave height to water depth H_(s_h)/(h_(r)+η^(-))is approximately constant;the dimensionless LF significant wave height Hs_l/H_(s0) and the dimensionless wave set-upη^(-)/[T_(p)(gH_(s0))1/2]can be related to the inverse wave steepness parameter gT_(p)^(2)/H_(s0) and the relative reef-flat submergence(h_(r)+η^(-))/H_(s0) respectively.
