Propagation of incident modulated waves past impermeable semi-infinite breakwaters

A possible source of resonant problems in a harbor is the long waves genera ted due to incident wave groups. For harbors protected by vertical breakwat ers the diffraction of the group could generate free long waves. Using a mu ltiple-scale perturbation method, the diffraction and reflection of a wave group past an impermeable semi-infinite vertical thin breakwater in horizon tal bottom is studied. The relationship between the incident wave group and the generated free and locked long waves is derived and an analytical solu tion is presented. It is shown that free long waves could be generated due to the wave group propagation past the breakwater and that the range of ang les for potential free long waves increases when the value of the relative depth decreases. (C) 2000 Elsevier Science Ltd. All rights reserved.