Wave Interactions with Multiple Semi-Immersed Jarlan-Type Perforated Breakwaters  

作　　者：Moussa S. ELBISY 

机构地区：[1]Civil Engineering Department, College of Engineering and Islamic Architecture, Umm A1-Qura University, Makkah 22195, Saudi Arabia

出　　处：《China Ocean Engineering》2017年第3期341-349,共9页中国海洋工程（英文版）

摘　　要：This study examines wave interactions with multiple semi-immersed Jarlan-type perforated breakwaters. A numerical model based on linear wave theory and an eigenfunction expansion method has been developed to study the hydrodynamic characteristics of breakwaters. The numerical results show a good agreement with previous analytical results and experimental data for limiting cases of double partially immersed impermeable walls and double and triple Jarlan-type breakwaters. The wave transmission coefficient Cv; reflection coefficient CR, and energy dissipation coefficient CE coefficients and the horizontal wave force exerted on the front and rear walls are examined. The results show that CR reaches the maximum value when B/L = 0.46n while it is smallest when B/L=0.46n＋0.24 （n=0, 1, 2,...）. An economical triple semi-immersed Jarlan-type perforated breakwater can be designed with B/L = 0.25 and CR and CT ranging from 0.25 to 0.32 by choosing a relative draft d/h of 0.35 and a permeability parameter of the perforated front walls being 0.5 for an incident wave number kh nearly equal to 2.0. The triple semi-immersed Jarlan-type perforated breakwaters with significantly reduced CR, will enhance the structure＇s wave absorption ability, and lead to smaller wave forces compared with the double one. The proposed model may be used to predict the response of a structure in the preliminary design stage for practical engineering.This study examines wave interactions with multiple semi-immersed Jarlan-type perforated breakwaters. A numerical model based on linear wave theory and an eigenfunction expansion method has been developed to study the hydrodynamic characteristics of breakwaters. The numerical results show a good agreement with previous analytical results and experimental data for limiting cases of double partially immersed impermeable walls and double and triple Jarlan-type breakwaters. The wave transmission coefficient Cv; reflection coefficient CR, and energy dissipation coefficient CE coefficients and the horizontal wave force exerted on the front and rear walls are examined. The results show that CR reaches the maximum value when B/L = 0.46n while it is smallest when B/L=0.46n＋0.24 （n=0, 1, 2,...）. An economical triple semi-immersed Jarlan-type perforated breakwater can be designed with B/L = 0.25 and CR and CT ranging from 0.25 to 0.32 by choosing a relative draft d/h of 0.35 and a permeability parameter of the perforated front walls being 0.5 for an incident wave number kh nearly equal to 2.0. The triple semi-immersed Jarlan-type perforated breakwaters with significantly reduced CR, will enhance the structure＇s wave absorption ability, and lead to smaller wave forces compared with the double one. The proposed model may be used to predict the response of a structure in the preliminary design stage for practical engineering.

关 键 词：Jarlan-type perforated breakwaters analytical solution eigenfimction least squares technique 

分 类 号：U656.2[交通运输工程—港口、海岸及近海工程]