Laboratory tests on the interaction between non-linear long waves and submerged breakwaters

This paper deals with the use of submerged detached breakwaters as beach protection, a use that today has become quite popular. This type of structure has been largely studied both theoretically and through experimental analysis in recent years, however its behavior has not been completely understood, specially if related to the real irregular wave attacks. In particular some laboratory studies carried out by the authors have pointed out some interesting phenomena associated with the interaction between the nonlinearities of wave transformations in shallow water and submerged breakwaters. Aiming at discerning between the phenomena related to the structure (beach and breakwater) and flume geometry, a new series of laboratory tests have been carried out in a 50 m long wave flume; these tests and the results obtained are described in this work. Besides the study of the behavior of submerged structures related to the bounded-long-waves, some current velocities have also been measured during this research through directional micro-propeller fluid meters.