Performance Analysis of a Semicircular Free Surface Breakwater

In the present study, the hydrodynamic performance of a semicircular free surface breakwater (SCB) has been investigated through a systematic experimental programme. Three semicircular breakwater models were tested: one with impermeable front and rear walls; a second with perforated front wall and impermeable rear wall; and a third with perforated front and rear walls. The models were tested for three submergence depths with reference to the still water level in a wave flume under irregular seas with different significant wave heights and peak periods. The performance of the breakwaters was evaluated in the form of coefficients of transmission (C_T), reflection (C_R) and energy dissipation (C_L). The measured wave modification in front of the structure and in the breakwater’s chamber were quantified and presented in the form of a ratio relative to the incident wave height, respectively. Also, the measured horizontal wave forces acting on the SCB were analysed and reported in a dimensionless form. Empirical equations were then developed using nonlinear multiple regression models to estimate the hydrodynamic characteristics of the SCB models.