Experimental and numerical analysis of the geometry of a laboratory-scale overtopping wave energy converter using constructal design

An experimental study is conducted to investigate the influence of the design of a laboratory-scale onshore overtopping device over the mass of water accumulated in its reservoir, and generate a database to validate computational models. The geometric evaluation is based on the constructal design, being investigated one degree of freedom (ratio between the height and length of the ramp, H1/L1) for various depths of free surface of the water (h1). Four geometric constraints delimit the ramps configurations. The exhaustive search is applied to obtain the ramp geometry that maximizes the amount of water that enters the device reservoir, represented by the water level accumulated in the reservoir (hR). For h1 = 0.392 m cases, a numerical model based on the finite volume method is also used for validation purposes. Results indicated that the lowest H1/L1 ratios of the ramp led to the best performances for all studied magnitudes of h1, which agreed with previous findings of literature for similar wave conditions. The proposed numerical model was validated for predicting wave propagation, instantaneous amount of water discharge, and prediction of the effect of H1/L1 over hR, with a maximum relative error (RE) of 3.92 %.