Accession Number : ADA260892


Title :   Experimental Inquiries into Collective Sea State Modes in Deep Water Surface Gravity Waves


Descriptive Note : Master's thesis


Corporate Author : NAVAL POSTGRADUATE SCHOOL MONTEREY CA


Personal Author(s) : Lawrence, Richard T


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a260892.pdf


Report Date : Dec 1992


Pagination or Media Count : 58


Abstract : An experiment designed to find collective sea state modes in deep water surface gravity waves was performed. The experiment was conducted in a large water tank with fans to create a wind driven background sea state. This background sea state may be more precisely referred to as a condition of wave turbulence. The background sea state was perturbed with an additional burst of waves created at one end of the tank by a computer controlled mechanical paddle. Different wind speeds and input burst waveforms were used. The wave height was measured with a four wire probe, with integrated circuit implementation. Data acquisition, manipulation, and averaging were automated. The probable collective mode can be seen in spectral density versus time images as a nondispersive decrease in background spectral density. It was estimated that this decrease in spectral density propagated independently of the input wave burst by examining its arrival time relative to burst energy arrival time for different probe to paddle distances. More importantly, it was determined that the propagation speed was a function of the background spectral peak frequency. Additionally, input burst energy at frequencies above the background spectral peak was not observed to propagate.


Descriptors :   *OCEAN WAVES , *SURFACE WAVES , *WIND , *SEA STATES , *AIR WATER INTERACTIONS , VELOCITY , FREQUENCY , ACOUSTIC WAVES , THESES , INTEGRATED CIRCUITS , IMAGES , WATER TANKS , GRAVITY WAVES , HEIGHT , DEEP WATER , OCEANS , SPECTRAL ENERGY DISTRIBUTION , CIRCUITS , DATA ACQUISITION , WAVE PROPAGATION , TURBULENCE , WAVEFORMS , ENERGY , COMPUTERS , DENSITY , PROBES


Subject Categories : Meteorology
      Physical and Dynamic Oceanography


Distribution Statement : APPROVED FOR PUBLIC RELEASE