Experimental investigation on the hydrodynamic performance of an inverted trapezoidal breakwater

The wave transmission, reflection, and dissipation characteristics of conventional (trapezoidal (TBs)) and non-conventional (inverted trapezoidal (ITBs) and rectangular (RB)) breakwaters with the same volume and porosity are evaluated under different submergence ratios, wave heights, and wave periods in regular and random waves. The experimental investigation revealed that the ITB shape is the most efficient cross section for reducing wave transmission coefficient (K-t) when the breakwater is submerged or the still water level (SWL) is at the crest of the breakwater, whereas the conventional TB is the least efficient. Compared to the conventional TB, the ITB reduced K-t by 10%-20% under submerged conditions and by 20%-30% when the SWL is at the breakwater crest. K-t < 0.2 is obtained for a relative water depth d/L-p > 0.2, which is suitable for most wave damping applications in the field when the ITB crest is at the SWL or when the crest emerges.