Energy evolution generated by waves propagate over submerged breakwater on a sloping bed

Submerged breakwaters have become increasingly popular due to their multiple functions, which are to protect shoreline or harbor and to prevent beach erosion in the coastal zones. In this paper submerged breakwater in the coastal zones was modeled in a wave flume. The experiment was outfitted with a servo-hydraulically actuated wave-maker at one end and a sloping bottom (slope=1:20) at other end for modeling water motion in the coastal region. Wave elevation measurements were made by using capacitance-type wave probes. Basic experiments are conducted on linear waves, nonlinear waves and irregular waves propagating over trapezoidal-type submerged breakwater on a sloping bed in the wave-flume. Based on wave spectrum analysis, the evolution of the wave energy through the submerged breakwater was investigated. Analyzing the relation between the depth of submergence and the characteristics of wave energy, the results of that fundamental energy decreases as the depth of submergence increases, the wave profile becomes strongly asymmetry and wave energy in lower harmonic is transferred into higher harmonic are presented. Under the linear and nonlinear waves, the changes of wave energy between before and after the submerged breakwater are shown that harmonic waves exhibit different.