DocumentCode :
1451289
Title :
Degradation of some mechanical current meter measurements by high-frequency mooring or wave motion
Author :
Loder, John W. ; Hamilton, James M.
Author_Institution :
Dept. of Fisheries & Oceans, Bedford Inst. of Oceanogr., Dartmouth, NS, Canada
Volume :
16
Issue :
4
fYear :
1991
fDate :
10/1/1991 12:00:00 AM
Firstpage :
343
Lastpage :
349
Abstract :
Comparison of current measurements from moored (paddle-wheel rotor) Aanderaa current meters and acoustic Doppler current profilers in a strong tidal flow on Georges Bank indicates rate under-reading by the Aanderaa meters at some vertical positions. The under-reading may arise from mooring-line vibrations induced by vortex shedding from spherical buoyancy packages, and shielding of the paddle-wheel rotors due to the meters´ inability to remain aligned with the fluctuating relative water velocity. Field tests and a simple model are used to investigate this explanation. The authors briefly review the Georges Bank observations that instigated this investigation. An explanation for the degradation of the Aanderaa measurements is proposed, observational information from field tests is discussed, and the model and its implications are presented. The model results support the hypothesis that high-frequency mooring-line vibration causes the degradation of the Aanderaa measurements
Keywords :
geophysical fluid dynamics; measurement errors; ocean waves; oceanographic equipment; oceanographic regions; oceanographic techniques; 12 to 64 m; AD 1988; Aanderaa current meters; Georges Bank; NW Atlantic Ocean; acoustic Doppler current profilers; continental shelf dynamics; fluctuating relative water velocity; high-frequency mooring motion; high-frequency mooring-line vibration; mechanical current meter measurements; meters misalignment; moored current meters; ocean currents measurements degradation; paddle-wheel rotors shielding; rate under-reading; spherical buoyancy packages; strong tidal flow; vertical positions; vortex shedding; wave motion; Acoustic measurements; Current measurement; Degradation; Mechanical variables measurement; Motion measurement; Pollution measurement; Sea measurements; Testing; Velocity measurement; Vibration measurement;
fLanguage :
English
Journal_Title :
Oceanic Engineering, IEEE Journal of
Publisher :
ieee
ISSN :
0364-9059
Type :
jour
DOI :
10.1109/48.90897
Filename :
90897
Link To Document :
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