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Estimates of water turbine noise levels

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Date Issued:
2011
Summary:
This work seeks to understand water turbine noise generation and to make preliminary estimations of the noise levels. Any structure attached to a turbine upstream its blades will generate unsteady fluctuating loads on the blade's surface, which are proportional to the radiated acoustic pressure. The noise levels of a simplified turbine based on existing designs surpass the ambient noise levels of the ocean at low frequencies (< 20 Hz) by approximately 50 dB ref 1 μPa and stay under the ambient noise levels at higher frequencies for a blade-passing frequency of 0.83 Hz and point of observation (100 m, 45 degrees, 45 degrees) from the hub. Streamlining the cross-section of the upstream structure as well as reducing its width decrease the noise levels by approximately 40 dB ref 1 μPa, at low frequencies and moderately increase them at higher frequencies. Increasing the structure-rotor distance decreases the noise levels with increasing frequencies (> 30 Hz).
Title: Estimates of water turbine noise levels.
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Name(s): Guerra, Julian.
College of Engineering and Computer Science
Department of Ocean and Mechanical Engineering
Type of Resource: text
Genre: Electronic Thesis Or Dissertation
Date Issued: 2011
Publisher: Florida Atlantic University
Physical Form: electronic
Extent: x, 82 p. : ill. (some col.)
Language(s): English
Summary: This work seeks to understand water turbine noise generation and to make preliminary estimations of the noise levels. Any structure attached to a turbine upstream its blades will generate unsteady fluctuating loads on the blade's surface, which are proportional to the radiated acoustic pressure. The noise levels of a simplified turbine based on existing designs surpass the ambient noise levels of the ocean at low frequencies (< 20 Hz) by approximately 50 dB ref 1 μPa and stay under the ambient noise levels at higher frequencies for a blade-passing frequency of 0.83 Hz and point of observation (100 m, 45 degrees, 45 degrees) from the hub. Streamlining the cross-section of the upstream structure as well as reducing its width decrease the noise levels by approximately 40 dB ref 1 μPa, at low frequencies and moderately increase them at higher frequencies. Increasing the structure-rotor distance decreases the noise levels with increasing frequencies (> 30 Hz).
Identifier: 729581411 (oclc), 3170958 (digitool), FADT3170958 (IID), fau:3633 (fedora)
Note(s): by Julian Guerra.
Thesis (M.S.C.S.)--Florida Atlantic University, 2011.
Includes bibliography.
Electronic reproduction. Boca Raton, Fla., 2011. Mode of access: World Wide Web.
Subject(s): Turbines -- Vibration -- Testing
Underwater acoustics
Fluid dynamics
Persistent Link to This Record: http://purl.flvc.org/FAU/3170958
Use and Reproduction: http://rightsstatements.org/vocab/InC/1.0/
Host Institution: FAU