Effects of bottom roughness on wave transmission across a submerged reef

This paper presents a laboratory study to investigate the effects of bottom roughness on wave transmission across submerged coral reef that has steep fore-reef slope. Experimented models were carried out in flumes for four different bed levels: including smooth and three heights. Our investigations showed there is significant dissipation energy short-period waves (SS-waves), owing friction, compared with infra-gravity (IG-waves). In addition, found IG-wave heights are increased slightly as propagate shoreward from reef-edge surfzone, indicating portion was transferred SS-waves IG-waves. Empirical formulae due friction non-linear transfer among SS- IG-waves have been derived; these allow straightforward determination periods reef. These local parameters can be used design offshore structures reefs.