The effect of the coastal reflection on the performance of a floating breakwater-WEC system

• Published in: Applied ocean research 2020-07, Vol.100, p.102117-9, Article 102117
• Main Authors: Zhang, Yang, Li, Mingwei, Zhao, Xuanlie, Chen, Lifen
• Format: Article
• Language: English
• Subjects: Analytical study; Breakwater; Breakwaters; Coastal reflection; Efficiency; Energy conservation; Energy transfer; Floating; Hydrodynamics; Irregular waves; Potential flow; Reflection; Regular waves; Standing waves; Water conservation; Wave attenuation; Wave energy; Wave energy converter; Wave power; Wave resonance
• ISSN: 0141-1187; 1879-1549
• DOI: 10.1016/j.apor.2020.102117

•The underlying physics involved in the effect of the coastal reflection considering different clearances was described.•A significant increment of the efficiency can be observed, accompanying the occurrence of the piston mode or sloshing mode resonance.•The wave attenuation performance of the floating system is modified significantly due to the presence of the coastal wall.•The valley values of the efficiency are found when the device is located at nodes of the waves. This is also corresponding to the null radiation damping of the body.•The performance of the breakwater-WEC system with the coastal wall in irregular waves was analyzed. In this paper, the hydrodynamic performance of a floating breakwater-Wave Energy Converter (WEC) integrated system was investigated under the framework of the linear potential flow theory, with a focus on the effect of the coastal reflection. The reflection coefficient and capture width ratio were verified using the rule of wave energy flux conservation. The water wave resonances, including the piston- and sloshing-mode, between the device and the coastal wall, were excited. By comparing to the cases without the coastal wall, the presence of the coastal wall led to the significant modifications of the hydrodynamic characteristics, efficiency and wave attenuation performance of the system. Specifically, the occurrence of the piston- and sloshing-mode resonance accompanies the increment of the efficiency of the system. The null efficiency was found when the device was located at the node of standing waves, which was formed due to the presence of the coastal wall. The effect of the coastal wall in irregular waves was found to be relatively milder when compared to that in regular waves.