Numerical Modeling of Hydrodynamic Performance on Porous Slope Type Floating Breakwater

• Published in: NAŠE MORE Vol. 70; no. 2; pp. 77 - 87
• Main Authors: Sujantoko, Sujantoko, Djatmiko, Eko Budi, Wardhana, Wisnu, Gemilang Firmasyah, Is Naldi
• Format: Journal Article Paper
• Language: English
• Published: Dubrovnik Sveuiliste u Dubrovniku 01.06.2023; Sveučilište u Dubrovniku
• Subjects: Abrasion; breakwater; Breakwaters; CFD; Coastal structures; Coasts; Coefficients; Computational fluid dynamics; Construction costs; Dimensions; Energy; Floating; Floating breakwaters; Fluid dynamics; High tide; Hydrodynamics; Low tide; Mathematical models; Mooring; Mooring lines; Mooring systems; Numerical models; Porosity; porous slope type floating; Reflection; Regular waves; Sedimentation & deposition; Soil erosion; transmission; Water depth; Water level fluctuations; Water levels; Wave energy; Wave height; Wave period; Wave power; Wave reflection
• ISSN: 0469-6255; 1848-6320
• DOI: 10.17818/NM/2023/2.1

A breakwater is a coastal building that aims to break up or withstand wave energy that enters the beach so that the characteristics of the incoming waves are by calculations and can reduce abrasion on the shoreline. Designing a floating breakwater is very complicated because it depends on many aspects. These fundamental aspects depend on each other, so if one of these aspects changes, the integrity of the floating breakwater structure will also change. One of these aspects is the magnitude of the transmission and reflection coefficients generated by the floating breakwater. This research will study the hydrodynamic performance of floating breakwater due to variations in slope and porosity in reducing and reflecting waves with computational fluid dynamics (CFD). The slope-porous floating breakwater dimension is based on previous experimental data, including a constant water depth of 0.75 m, a wave height of 0.05 - 0.125 m, and a wave period of 1.1 - 2 sec on regular waves. The results of the numerical model validation and experiments on all variations of the floating breakwater model are quite good, which is less than 10% for both wave transmission and reflection. Analysis of the influence of changes in the mooring line angle, the simulation is carried out at an angle of 30 deg to 90 deg and produces an average transmission coefficient of 0.79 and a reflection of 0.21. While the effect of changes in water level elevation (0.85 m, 0.75 m, and 0.65 m) gives a reasonably significant average transmission coefficient of 0.85 and a reflection of 0.13. The mooring line angle will be gentler at high tide, and the transmission and reflection coefficients will be higher. However, the mooring line will loosen at low tide, causing the structure to move more freely and eliminating the function of the floating breakwater itself so that the tidal phenomenon becomes a challenge for coastal experts in designing structures to produce effective and efficient hydrodynamic performance.