EXPERIMENTAL STUDY OF NEAR SEABED FLOW FIELD AND WAVEPROPAGATION OVER SUBMERGED BREAKWATER ON THE SLOPE

摘要

Submerged breakwaters have become increasingly popular due to theirmultiple functions, which are to protect shoreline or harbor and to prevent beacherosion in the coastal zones. In this paper trapezoidal submerged breakwater in thecoastal zones was modeled using a wave flume. Based on the experimental datacollected, characteristics of changing wave profile, energy spectrum, statistic andspectrum parameters of regular waves and flow were calculated and analyzed,including 3D instantaneous velocities, turbulence intensity, Reynolds stress, turbulentkinetic and power spectrum of turbulent flow velocity. The result shows that the waveprofile becomes strongly asymmetry and wave energy in lower harmonic is transferredinto higher harmonic. At the back of submerged breakwater the wave energy rapidlydecreases. The fluid motion near the bed is turbulent and the pulsating velocity showsthat the turbulence intensity near the bed is larger than the turbulence intensity faraway from the bed. The higher harmonics generate and intensify near the bottom orwhen the water depth decreases. Especially on the top of submerged breakwater, theturbulence intensity, Reynolds stress and turbulent kinetic energy becomeextraordinarily strong.