STUDY OF THE REFLECTION COEFFICIENT OF A WAVE ON AN INCLINED PLANE

Abstract

This paper is intended to make a further contribution, based on laboratory experiments, to the many tests carried out to date on the problems of the reflecting capacity of an obstacle attacked by waves. Systematic measurements made in a wave flume at the Laboratoire Dauphinois d'Hydraulique, with obstacles formed by plane surfaces inclined between 0 and 90 degrees, have made it possible to plot a graph showing the variation of the reflection coefficient for a wave approaching these obstacles in a normal direction, in relation to the slope of the latter and the shape of the wave. It has also been possible to ascertain the effect of the wall roughness, because some tests were made with rock-filled breakwaters. A comparison has been made between the experimental curves obtained in this way and Miche's theoretical curves. This has shown that the latter appear satisfactory, and it has made it possible to investigate some points with Miche himself thought should be clarified by tests in a laboratory. A graph of this kind can be of great value for estimating the reinforcement of disturbance near sea structures. This disturbance often makes navigation and berthing difficult. But the full understanding of these curves can lead to the knowledge of whether a talus or a beach has a sufficiently gentle slope to efficiently protect a coastline by distributing the energy of waves before they reach the area which must be protected.