Hydrodynamic characteristics and wave attenuation on the double-row tri-leg floating breakwater

The present research focuses on the hydrodynamic characteristics and wave attenuation capabilities of double-row tri-leg floating breakwater (FB) systems with varying side leg angles. Regarding the dynamic response of the FB, the boundary element method (BEM) based on potential flow theory is employed. Numerical simulations were conducted to analyze response amplitude operator (RAO). The results are carried out under different parameters included wave periods, side leg angles, and distances between two FBs. The results of the added mass, radiation coefficient, wave force, three motions of sway, heave and roll RAO, wave transmission coefficient are presented and discussed. The 50^°and 60^°configurations show the highest RAOs in sway and heave motions, particularly at intermediate wave periods (1.4-1.7s), indicating strong wave energy absorption. Increasing the spacing from 1.5m to 2.5m generally reduces RAOs for the 50^°-60^°FBs, highlighting diminished hydrodynamic coupling at wider spacings. The 50^°and 60^°configurations also demonstrate superior wave attenuation, particularly at intermediate spacings (1.75 m- 2.25 m), with transmission coefficients generally decreasing as spacing increases. The side leg angle of 90 is consistently underperforms regarding wave interaction, damping, and attenuation.