Title page for etd-0829108-152831


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URN etd-0829108-152831
Author Yi-wei Lin
Author's Email Address No Public.
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Department IAMPUT
Year 2007
Semester 2
Degree Master
Type of Document
Language zh-TW.Big5 Chinese
Title Effects of Waveguide Properties on Surface-Generated Ambient Noise: Simulation and Analyzed
Date of Defense 2008-07-26
Page Count 77
Keyword
  • Random Sources
  • Ambient Noise
  • Gaussian
  • Waveguide
  • Abstract Ambient noise generated by surface random processes is the primary contribution to the noise-field energy in the intermediate frequency band, and thus is important in many applications of underwater sound. In this study, the noise field is analyzed with respect to the effects of random source spectrum, waveguide structure of the water column, and seabed stratifica¬tion upon the noise-field intensity as well as spatial correlation. Based upon a noise-generation model due to continuous random sources, incorporating several analytical models for seabed stratification, a formulation may then be derived to facilitate the numerical implementation. Many results shall be generated and analyzed. In this study considers the noise field generated by wave in an oceanic environment with a sediment layer possessing a constant density and sound-speed profile. This model closely resembles the oceanic waveguide environment and therefore enables the simulation of surface noise generation. Many results of the noise field were generated, in¬cluding the noise intensity distribution, vertical and horizontal correlations. It is demonstrated that the noise intensity may be affected by the strat¬ification mainly through the continuous spectrum, in that the continuous spectrum is equally important as the normal modes in the present analysis. Moreover, the results for the correlations show that the noise field in the horizontal direction becomes more coherent when the noise sources are more correlated, while in the vertical direction, the results tend to reverse. The horizontal correlations of the noise field due to surface random sources with non-isotropic power spectrum, such as non-isotropic Gaussian and, were generated and analyzed.
    Advisory Committee
  • Bin-bing Ma - chair
  • Chen-fen Huang - co-chair
  • Jin-yuan Liu - advisor
  • Files
  • etd-0829108-152831.pdf
  • indicate access worldwide
    Date of Submission 2008-08-29

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