A LABORATORY EXPERIMENT ON SURFACE WAVE ATTENUATION DUE TO UNDERWATER TURBULENCE.
NAVAL POSTGRADUATE SCHOOL MONTEREY CALIF
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The attenuation of surface waves caused by underwater turbulence was investigated in a wave-tank experiment. The waves studied frequencies ranging from 1.2 to 12.3 Hertz were strongly attenuated by a zone of grid-generated turbulence. This attenuation depended on the length of the turbulent region, and on the frequency of the incident wave. The equation governing attenuation was h h sub 0 exp-ax where h is wave height, h sub 0 is undisturbed wave height, x is the length of the turbulent region, and a is an attenuation coefficient proportional to the cube root of frequency. It was also noted that the waves were shifted in phase as they passed through the turbulence, and that the magnitude of this shift increased with frequency. The quantitative results of the experiment were obtained from measurements of nearly sinusoidal waves. They were confirmed, qualitatively, for a continuous spectrum of waves by measurement of wind-generated model sea surface. Author
- Physical and Dynamic Oceanography