Laboratory investigation of short wind wave breaking modulation in the long surface wave field

摘要

Both the modulation of short wind wave breaking in the long surface wave field and the occurrence of breaking in the presence of a long wave were investigated in wind-wave tank. Short wind waves were generated by the air flow at various speeds, the long surface wave at various frequency and amplitude were generated by wave maker. Data of X- and Ka-band scatterometers, string wave recorder placed in the probing area, and web camera making video records of the probing area were synchronously recorded in the experiment. Also precision measurements using laser-optics system based on the high-speed video recording, laser illumination, and special algorithms of video processing allowed us to obtain a large ensemble of the wave profiles. It is shown that at relatively weak wind long surface wave causes short wind wave breaking, and at high wind speeds - breaking intensification. Wind wave breaking is mainly observed on the front slope of the long wave, the breaking observation area extends with increasing wind speed.