Performance evaluation of a semicircular breakwater with truncated wave screens

A semicircular breakwater model with rectangular perforations and with truncated wave screen(s) of different porosities has been developed in this study which could act as an anti-reflection wave barrier, providing wave protection to coastal and marine infrastructures. The hydrodynamic performance of the breakwater model is evaluated through wave measurements in a wave flume under irregular waves. The experiments are undertaken with three setups; (i) a wave screen is attached to the front curved wall of the semicircular breakwater and none at the rear wall, (ii) a wave screen is attached at the rear curved wall of the semicircular breakwater and none at the front wall and (iii) wave screens one each is attached to the front and rear walls of the semicircular breakwater. The wave surface elevations are measured at different locations upstream and downstream of the breakwater model and the coefficients of wave transmission, reflection and energy dissipation are determined. Wave climate in the vicinity of the breakwater and the horizontal wave force on the model are also measured and analysed. The results show that the semicircular breakwater with double screens of 25% porosity is the most viable design that offers reasonably good hydraulic performance as this acts as an energy dissipater rather than a wave reflector. Further, empirical models developed using a multi-regression method for estimation of reflection, transmission and energy loss coefficients as well as the normalised wave force coefficients, correlates well with the experimental data.