The variation of the velocity and turbulent kinetic energy field in the wave in the vicinity of the breaking point

Abstract

The paper describes experimental investigation of the flow and turbulent kinetic energy under the weakly plunging breaking wave in the outer surf zone. Experiments for the present study were carried out on a surf zone model with a constant slope of 1 : 17 in the vicinity of the wave breaking point. Experimental results show that the kinetic energy is largest under the wave crest and decreases rapidly after the wave crest has passed. Visualization of the flow proved that the velocity profile during backflow phases resembles the steady open channel flow, but during the onflow phases the velocity profile is unlike any other flow situation.

An experimental investigation of the oscillatory boundary layer around the breaking point

“…This phase shift is initiated by the hydrodynamic processes in the wave. The same phase lag was also noticed in [ 24 ].…”

“…The following results on experimental investigation of oscillatory flow were obtained during experiments, described in [ 24 ]. The goal was to compare the measured velocity distribution in the boundary layer with velocity distributions, used in mathematical models.…”

“…The total number of wave cycles, sampled at each measuring point, was 151. The data processing procedures and main results of investigations are described in [ 24 ]. The main attention in the study was focused on the determination of the velocity field inside the breaking wave, especially in the area close to the bottom of the surf zone, where data was collected with the vertical step of 1 mm.…”

“…The data processing smoothened the curve and also got rid of drop-outs between 360 t ω = and 720 t ω = deg. Data processing is described in detail in [ 24 ].…”