Hydrodynamic Characteristics of Concave Front Pile-Supported Breakwaters with a Tubular Wave Screen

Abstract

Concave front pile-supported breakwaters, namely, Galveston wall-shaped pile-supported breakwater (GS-PSB) and circular cum parabola-shaped pile-supported breakwater (CPS-PSB), have proven to be more effective in dissipating incident wave energy compared with vertical front pile-supported breakwaters. However, the run-up and the dynamic pressures on the concave front are reported to be high. In the present experimental study, an attempt is made to improve the hydrodynamic performance of the GS-PSB and CPS-PSB by mounting tubular wave screens on their seaside as an additional energy dissipator. The tubular wave screen is comprised of horizontally aligned circular tube sections with diameter and spacing leading to a porosity of 25%. The models were subjected to the action of regular and random waves in a wave flume covering intermediate to deepwater conditions. It is found that the impact of tubular wave screen on the hydrodynamic performance of the both the models differs. While, the tubular wave screen marginally affects the transmission, the reduction in reflection is more for GS-PSB due to its steeper slope. The energy dissipation offered by GS-PSB in deepwater conditions is found to significantly improve due to the presence of the wave screen, which is not the case with the CPS-PSB model. The run-up and dynamic pressures over the concave profiles are found to reduce for both models. A qualitative assessment of overtopping for both the models is also reported herein.