DISCONTINUOUS COMPOSITE WAVE ABSORBER STUDIES

Abstract

An experimental study was conducted to determine the energy dissipation characteristics of a discontinuous wave absorber consisting of an impervious lower slope and a stone-filled upper slope. The purpose was to determine the wave energy absorption as a function of the incident wave parameters and the wave absorber geometry. Parameters varied were wavelength, wave height, lower and upper absorber slopes, berm depth and width, and stone size. For virtually all test conditions, a minimum wave reflection was found when the discontinuity (berm) depth was at one-quarter to one-half the water depth below the water surface. The overall wave absorption increased under the following conditions: an increase in horizontal berm width of up to five layers of stone; a decrease in the angle of the upper (stone-filled) slope when the berm depth is below one-fifth the water depth; and a decrease in the angle of the lower (impervious) slope when the berm depth is above one-half the water depth. The results should be useful where water wave reflections must be minimal and space is limited, such as in harbor walls or for hydraulic models.