Acoustic noise generation under plunging breaking waves*

The paper presents results of investigations performed in a wave channel in order to determine associations between the dissipation of surface wave energy during breaking and acoustic noise emission.The experiments were carried out in fresh water in the Large Wave Flume (GWK) at the Forschungszentrum Küste (FZK) in Hanover (Germany). Relationships between the acoustic noise energy and losses of surface wave energy were estimated over the broad acoustic frequency band from 350 to 12500 Hz, and the characteristic temporal changes of the spectral properties of noise in the breaking process were demonstrated.It was found that the ratio of acoustic noise energy generated during wave breaking to the energy dissipation of single plunging breakers with heights of 1.6–2.8 m were in the 10−9–10−8 range and found to be in reasonable agreement with the results of some previous experiments performed for smaller scales of breaking wave.The study contributes to the development of a passive acoustic method for the parameterization of sea surface dynamic processes.