Bulk Wave Dissipation in the Armor Layer of Slope Rock and Cube Armored Breakwaters

Abstract

The objective of this research is to analyze the interaction of the incident wave train with a mound breakwater (specifically, dissipation in the armor layer) and to quantify the performance of the structure built with different types and sizes of armor units. The generalized Π -Buckingham theorem is invoked to choose a complete set of independent variables that govern the principal interaction processes. The analysis is based on two sets of experimental data obtained in the wave flume of IISTA, University of Granada, and in the wave flume of Aalborg University. The bulk dissipation depends on the product of the relative water depth and the incident wave steepness, (h/L)(HI/L), the relative size of the armor diameter, Da/HI, the relative thickness, e/L, the shape and specific placement criterion, the characteristics of the porous core, B∗/L, D50,p/L, and the slope angle of the breakwater. For a given breakwater, the product of (h/L)(HI/L) can be used to identify and quantify three hydrodynamic performance regimes: reflective, dissipative and transitional, based on the prevalent interaction processes. Moreover, the dimensional analysis provides a functional relationship between the stability parameter and the bulk dissipation. For two mound breakwaters, one built with cubes of Da=49.6 mm and the other one with rocks of Da=44.0 mm, the bulk dissipation is almost similar over the entire range of (h/L)(HI/L). These results could be useful for the assimilation of data obtained in different wave flumes, the optimization of the breakwater design and to revise the notional permeability parameter.