Experimental Investigation of Performance of Reef Breakwaters

Abstract

Reef breakwater is a low crested, rubble mound breakwater without a conventional multilayered cross section. It has been identified that transmission coefficient is one of the main parameters to quantify the performance of reef breakwaters and several parameters that influence transmission coefficient was identified. Accordingly, a comprehensive laboratory investigation was carried out and transmission of different reef breakwaters was studied by varying different influence parameters. It was observed that wave steepness, crest width and depth of crest submergence are the most influential parameters on transmission coefficient. Comparison between existing equations to calculate transmission coefficient was done using data from the present study. When using existing equations for the same input parameters, it can be seen that estimated transmission coefficient values differ from each other suggesting that their applicability to a real life problem is questionable. Therefore a new improved formula to estimate transmission coefficient was derived using dimensional analysis incorporating more influence parameters than existing equations. This formulation proved to be better than the previous equations.