Experimental and Numerical Study on the Hydrodynamic Performance of Suspended Curved Breakwaters

Abstract

The purpose of breakwaters is to protect the ports, beaches, or beach facilities from strong waves and storms, as they help establish calm inside the port and thus achieve safety for ships and ease of operation. This paper presents an experimental and numerical study of unconventional alternatives to the vertical breakwater in order to evaluate the hydrodynamic performance of the proposed models. Two proposed cases for a semi-submerged breakwater were selected in the form of a half-pipe section with an inside diameter of 20 cm and a thickness of 1 cm. Case (a) was of the concave type of semicircular breakwater, while case (b) was of the convex type. Numerical modeling FLOW 3D was used to construct numerous scenarios for numerical simulation of the proposed breakwaters. The obtained results indicates that, when comparing the wave transmission coefficient (Kt) and its reflection coefficient (Kr) with the relative water depth (h/L), the transmission coefficient decreased with the relative height of the wave, while the reflection coefficient was completely reversed. In case (a), Kt was less than in case (b) at a range of 10% to 15%, while Kr in case (a) was bigger than in case (b) at a range of 5% to 10%. When the wave hit the breakwater, it was reflected back as its energy is dissipated in less water depth and its speed decreases as it approaches the port. The velocity of the wave decreases as it approaches the bottom, which means that the wave is affected by the depth of the water, i.e. the lower the water depth, the lower the wave velocity. Case (a) was more efficient and effective in wave dissipation, current velocity, and bed stability than case (b), so it is recommended to use case (a) due to its efficiency in protecting coastal areas and generating electricity.