Effect of hole shapes of perforated breakwaters on incident wave energy damping using numerical method

Perforated breakwaters are newer generation of vertical breakwaters in which some how the problems of high wave reflection and forces exerted to the structure have been solved. In this paper the effect of hole shapes of vertical perforated breakwaters on reflection of solitary waves was investigated using numerical method. A single and double walls vertical breakwater with four different hole shapes and four different front wall porosity were considered. The breakwater was modeled in 3D using FVM method of FLOW-3D software. The free surface was modeled using VOF method while RNG-k-ε was used to model turbulent effect. The results show that in single wall breakwater as porosity increases the wave reflection increases as well so that a 40% porous wall reflects 90% of incident waves. Furthermore the reflection coefficient has a fluctuating nature as non- dimensional ratio of B/L increases (B is width of caisson and L is incident wave length). Moreover double wall breakwater is able to damp wave energy up to 20 to 25% greater than that of the single wall.