Development of an analytical model to studywave motion to through porough porous vertical to coastalstructures

Abstract

This study is concerned with the development of an analytical model to predict wave reflection and transmission characteristics of porous, vertical coastal structures. Because of the complexity of the problem the study was limited to non-breaking, small amplitude, long waves normally incident to the structure. The input data for the model are the incident wave characteristics and the properties of the porous media. The wave climate is identified by the wave height, the wave period and still water depth. The porous structure is characterised by its length, overall porosity and the laminar and turbulent flow coefficients (determined under steady flow conditions). The Forchheimer equation was used for the hydraulic gradient-velocity relationship. Continuity and momentum equations are linearised for the inclusion in the model. The model was verified with results obtained from hydraulic model investigations carried out at Imperial college, London and Lanka hydraulics institute, Sri Lanka. Satisfactory agreement was obtained between experimental and predicted values. 11