SHOALING AND REFRACTION OF SHIP WAVES

Waves generated by ship navigation become a subject of discussion from the viewpoints of various utilization and ecological environment preservation in a coast. In the present paper, the method of numerical simulation for ship waves was applied to open sea with a constant water depth and a coast with straight, parallel depth contours in order to investigate characteristics of propagation and transformation of ship waves. The ship length is 76m, the breadth is 11.5m, and the draft is 2.5m. The ship sails on a straight course of 12m deep with a constant speed. The ship speed is changed to cover so that the range of Froude number at the sailing depth is from 0.6 to 1.2. Transformations due to shoaling and refraction occur when the ship waves propagate on the sloping coast. The ship waves are greatly influenced by the depth Froude number. When the ship speed is near-critical at the sailing depth, the maximum wave height exceeds 1.5m at the water depth of 1m.