Evaluation of Wave Transmission Coefficient at Low Crested Structures in 3D Conditions Using Residual Analysis

Abstract

Systems of Low Crested Structures (LCS) are widely used for the protection and restoration of eroded shoreline due to their advantages especially in environmental aspects. Functional design of LCS requires an accurate crest level, provided by the estimation of wave transmission in the sheltered area. The wave transmission, defined by the transmission coefficient Kt, is estimated by formulae based on 2D experiments. In 3D conditions, other phenomena affect Kt and the predicted values for Kt differ. In the present paper, experimental results from two 3D series dealing with emerged LCS were analyzed and a new formula for Kt prediction, based on the recalculation of d’Agremond et al. (1998) formula, is presented. Experimental results were compared to four existing formulae of transmission coefficient - including the new one - and are evaluated using residual analysis. The new proposed formula has a very good agreement between measured and predicted values of Kt in 3D conditions, better than the predicted values by the other formulae based on 2D experiments, and can be used in the preliminary design of structures. The new proposed formula by the authors satisfies all the regression assumptions.