Experimental Inquiries Into Collective Sea State Modes In Deep Water Surface Gravity Waves

Experimental Inquiries Into Collective Sea State Modes in Deep Water Surface Gravity Waves

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.

Masters Theses in the Pure and Applied Sciences

Masters Theses in the Pure and Applied Sciences was first conceived, published, and disseminated by the Center for Information and Numerical Data Analysis and Synthesis (CINDAS)* at Purdue University in 1957, starting its coverage of theses with the academic year 1955. Beginning with Volume 13, the printing and dis semination phases of the activity were transferred to University Microfilms/Xerox of Ann Arbor, Michigan, with the thought that such an arrangement would be more beneficial to the academic and general scientific and technical community. After five years of this joint undertaking we had concluded that it was in the interest of all concerned if the printing and distribution of the volumes were handled by an international publishing house to assure improved service and broader dissemination. Hence, starting with Volume 18, Masters Theses in the Pure and Applied Sciences has been disseminated on a worldwide basis by Plenum Publishing Corporation of New York, and in the same year the coverage was broadened to include Canadian universities. All back issues can also be ordered from Plenum. We have reported in Volume 38 (thesis year 1993) a total of 13,787 thesis titles from 22 Canadian and 164 United States universities. We are sure that this broader base for these titles reported will greatly enhance the value of this impor tant annual reference work. While Volume 38 reports theses submitted in 1993, on occasion, certain uni versities do report theses submitted in previous years but not reported at the time.

Experimental Inquires Into Collective Sea State Modes in Deep Water Surface Gravity Waves