DocumentCode :
823957
Title :
Moored fish cage dynamics in waves and currents
Author :
Fredriksson, David W. ; Swift, M. Robinson ; Eroshkin, Oleg ; Tsukrov, Igor ; Irish, James D. ; Celikkol, Barbaros
Author_Institution :
Center for Ocean Eng., Univ. of New Hampshire, Durham, NH, USA
Volume :
30
Issue :
1
fYear :
2005
Firstpage :
28
Lastpage :
36
Abstract :
Recent work in the area of open ocean aquaculture system dynamics has focused separately upon either the response of fish cages in waves or the steady drag response due to ocean currents. In reality, however, forcing on these open ocean structures is a nonlinear, multidirectional combination of both wave and current profiles. At the University of New Hampshire-operated Open Ocean Aquaculture site, data were collected from a wave measurement buoy and a downward-looking Acoustic Doppler Current Profiler to characterize the surface elevation and water velocity profiles during an extreme northeast storm event. In addition to waves and currents, fish cage motion response in heave, surge, and pitch was inferred from accelerometer measurements during the same storm. The environmental data sets obtained during the peak of the storm were processed, analyzed, and used as input to a dynamic finite-element model. Simulations were performed using three load case scenarios: 1) in both waves and currents; 2) in waves only; and 3) in currents only. Model motion response results in both the time and frequency domain were compared with data obtained in situ . In addition to the motion response tests, the wave and current forcing influencing the mooring line tension response was also investigated. Analysis shows that in this case, the currents do not severely influence the oscillatory motion response, but do cause the cage to tilt, layback, and sink. The wave and current interaction effect did, however, influence the anchor line loads with a portion being attributed to nonlinear effects.
Keywords :
aquaculture; computational fluid dynamics; finite element analysis; flow simulation; ocean waves; oceanographic equipment; current profile; dynamic finite-element model; finite-element modeling; fish cage dynamics; fish cage motion response; frequency domain; model motion response; mooring systems; ocean currents; ocean waves; open ocean aquaculture system dynamics; open ocean structures; surface elevation profile; time domain; water velocity profile; wave profile; wave-current forcing; Acoustic measurements; Aquaculture; Current measurement; Marine animals; Nonlinear dynamical systems; Oceans; Sea measurements; Storms; Surface acoustic waves; Velocity measurement; Field measurements; finite-element modeling; fish cage and mooring systems; wave-current forcing;
fLanguage :
English
Journal_Title :
Oceanic Engineering, IEEE Journal of
Publisher :
ieee
ISSN :
0364-9059
Type :
jour
DOI :
10.1109/JOE.2004.841412
Filename :
1435574
Link To Document :
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