REFLECTION AND TRANSMISSION COEFFICIENTS FOR LOWCRESTED STRUCTURES. ASSESSMENT, UNCERTAINTIES ANDIMPLICATIONS

摘要

Low crested detached structures are commonly used for coastal engineering purposes. However the functional design presents a number of difficulties due to the large numbers of variables involved in the resulting coastal morphodynamics. Among these variables wave reflection and transmission play a key role in the resulting beach-structure interactions. Wave transmission controls the wave field behind the structure and therefore its sheltering effect. Wave reflection controls the sediment transport in front of the structure and, eventually, its own stability. This paper addresses the variability and uncertainties of reflection and transmission coefficients. It presents new data sets obtained at the large scale CIEM Wave Flume of the Maritime Engineering Laboratory (LIM/UPC) in Barcelona. It analyses critically the functional dependence of transmitted and reflected waves and it proposes and improved formulation. Finally it touches briefly upon the implications of such uncertainties and formulations.