Hydrodynamic performance of vertical porous structures under regular waves

Abstract

The hydrodynamic efficiency of the vertical porous structures is investigated under regular waves by use of physical models. The hydrodynamic efficiency of the breakwater is presented in terms of the wave transmission (k t), reflection (k r) and energy dissipation (k d) coefficients. Different wave and structural parameters affecting the breakwater efficiency are tested. It is found that, the transmission coefficient (k t) decreases with the increase of the relative water depth (h/L), the wave steepness (H i/L), the relative breakwater widths (B/L, B/h), the relative breakwater height (D/h), and the breakwater porosity (n). The reflection coefficient (k r) takes the opposite trend of k t when D/h=1.25 and it decreases with the increasing h/L, H i/L and B/L when D/h≤1.0. The dissipation coefficient (k d) increases with the increasing h/L, H i/L and B/L when D/h≤1.0 and it decreases when D/h=1.25. In which, it is possible to achieve values of k t smaller than 0.3, k r larger than 0.5, and k d larger than 0.6 when D/h=1.25, B/h=0.6, h/L≥0.22, B/L≥0.13, and H i/L ≥0.04. Empirical equations are developed for the estimation of the transmission and reflection coefficients. The results of these equations are compared with other experimental and theoretical results and a reasonable agreement is obtained.