Quantitatively study on wave-turbulence interactions by laboratory experiments

Ocean turbulent mixing influences the air-sea exchanges of heat, momentum and mass. The surface gravity waves play a key role in turbulence generation in the upper ocean. How wave energy is transferred to ocean turbulence through the wave-turbulence interactions remains an open question. In order to study this question, laboratory experiments were carried out in a wave tank to investigate the wave-turbulence interactions. Based on their power spectra, the turbulence intensities before and after the wave-turbulence interactions were compared quantitatively, and the experimental results indicate that the background turbulence energy among 7 and 20 Hz of its power spectrum increased approximately by 23.3% through wave-turbulence interaction. Using the Holo-Hilbert spectral analysis method, the results clearly show that the turbulence was modulated by surface waves and then enhanced through the wave-turbulence interaction process. When the surface wave is strong with a wave height of 7 cm, the modulation occurs in both the wave trough and crest phases. In addition, the intensity of the wave-turbulence interaction increases with the wave height and is proportional toHs(2).