Degradation of paddle-wheel Aanderaa current measurements by mooring vibration in a strong tidal flow

Author

Loder, John ; Hamilton, James

Author_Institution

Dept. of Fisheries & Oceans, Bedford Inst. of Oceanogr., Dartmouth, NS, Canada

fYear

1990

fDate

3-5 Apr 1990

Firstpage

107

Lastpage

119

Abstract

Currents measured with modified (paddle-wheel rotor) Aanderaa current meters on subsurface moorings in a strong tidal flow are compared to those measured with a ship-mounted acoustic Doppler current profiler (ADCP), a bottom-mounted ADCP, and InterOcean S4 electromagnetic current meters. Significant discrepancies among the rate measurements at some vertical levels are found. The rates measured by the Aanderaas at interior mooring positions are up to 20% lower than the acoustic rates, particularly for speeds greater than 0.8 m/s. Field tests and a simple model suggest that this discrepancy arises from shielding of the Aanderaa rotors due to instrument misalignment (with the relative water velocity) during periods of mooring vibration, induced by vortex shedding from in-line backup buoyancy packages

Keywords

flow measurement; oceanographic techniques; current meter; instrument misalignment; measurement; mooring vibration; ocean; paddle-wheel Aanderaa current measurements; strong tidal flow; technique; Acoustic measurements; Acoustic testing; Current measurement; Degradation; Electromagnetic measurements; Fluid flow measurement; Instruments; Particle measurements; Position measurement; Velocity measurement;

fLanguage

English

Publisher

ieee

Conference_Titel

Current Measurement, 1990., Proceedings of the IEEE Fourth Working Conference on

Conference_Location

Clinton, MD

Type

conf

DOI

10.1109/CURM.1990.110897

Filename

110897