Physical Model Simulation: Influences the Shape of Breakwater Structures on the Coefficient of Transmission and Reflection

Abstract

Breakwater is used to break the wave energy that travels towards the beach. Part of the wave energy will be destroyed, transmitted, or reflected. The shape of breakwater affects the ability to break the wave energy. There are no researchers who have compared the effect of the shape of the breakwater structure on wave energy transmitted and reflected. This study aims to simulate the transmission coefficient (Kt) and reflection coefficient (Kr) of the breakwater in various forms. Physical models with a 1:100 scale model is used. A flap-type wave generator in a wave flume is used to generate the wave. Waves regularly move in one direction passed the model. The results showed an effect of the shape of the breakwater structure on Kt and Kr. By increasing the wave steepness (Hi/L), Kt's value will increase in the upright structure and decrease in the sloping structure. At the same time, the value of Kr tends to decrease when the wave steepness increases. The value of Kt is relatively smaller in upright structures than in sloping structures. By adding porosity to the structure, the Kt value will increase, followed by Kr's reduction. By increasing the crest B's width, Kt appears to increase, but the crest width does not significantly affect Kr. Kt and Kr are significantly smaller if the breakwater structure is inclined towards the sea or inverted trapezium. This type of breakwater has never been encountered in the field before.