Study on the effect of the triangular cogged floor of floating breakwaters on wave transmission coefficient

Abstract Floating breakwaters are commonly utilized in certain marine areas where conventional breakwaters are not viable, such as locations with temporary requirements for installation (i.e., seasonal ports), environmental considerations, and significant tidal ranges, etc. The operation of floating breakwaters in deep waters with short-crested waves is generally diagnosed correctly. The transmission coefficient, which measures the fraction of radiation transferred by a floating breakwater, is typically used to determine the efficiency of these structures. This key parameter may be calculated using physical and/or numerical models. This study investigated thirteen different geometries in two groups of the same volume and draft on a laboratory scale using the FLOW-3D software. Then, the impact of the wave number, wave steepness, the breakwater’s weight, and draft were investigated using FLOW-3D. The numerical results for a model were first verified against experimental data from a pontoon breakwater, and having established the model’s accuracy, a systematic parametric study was carried out to compare wave‐attenuation performance across a range of geometries. Subsequently, several triangular cogs were formed at the bottom of the floating structures. The numerical results show that creating these variations can improve the efficiency of these structures by up to 45.32% compared to simple flat-bottomed. In terms of the transmission coefficients, the results of the first group (same volume) rendered the breakwater more effective than those of the second group (same draft). Furthermore, the findings of this study will provide insights into the engineering principles underlying the design of a floating breakwater for spectral (random) waves.