Offshore Breakwaters in Laboratory and Field

Small‐scale model tests for single and multiple offshore breakwaters were performed in a spiral wave basin to examine the effects of their geometric parameters on the morphological change in their vicinity. The model results are compared with physical model studies reported by others and with offshore breakwaters in the field. All the horizontal lengths are nondimensionalized with respect to the offshore distance of the breakwater from the original shoreline, XB. Three dimensionless variables, Xb*(=Xb/XB),LB*(=LB/XB), and GB*(=GB/XB), are found to be important, in which Xb,LB, and GB are the surf zone width, the length of breakwater, and the gap spacing between adjacent breakwaters, respectively.