High porosity net drag at a low angle of attack in application to a representative prawn trawl
The presented work investigated the extent by which Reynolds number determines the drag coefficient for high porosity nets at a low angle of attack. A simple prawn trawl model that incorporates the main design features of prawn trawls employed in Australia was developed. Four trawl models of various...
| Published in: | Volume 7: Ocean Space Utilization; Ocean Renewable Energy |
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| Main Authors: | , , , |
| Format: | Conference Object |
| Language: | English |
| Published: |
American Society for Mechanical Engineers (ASME)
2012
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| Subjects: | |
| Online Access: | https://doi.org/10.1115/OMAE2012-83083 http://ecite.utas.edu.au/79059 |
| Summary: | The presented work investigated the extent by which Reynolds number determines the drag coefficient for high porosity nets at a low angle of attack. A simple prawn trawl model that incorporates the main design features of prawn trawls employed in Australia was developed. Four trawl models of various high porosities were tested in a flume tank with respect to drag and shape over a range of flow velocities. The physical trawl model was analysed as a system of independent plane net sheets, each with an orientation to the flow estimated from analysis of stereo-vision data. The main finding was that the drag coefficient was weakly dependent on the Reynolds number in the range typical for prawn trawl operations, 1000 < Re < 1700 . These combined findings imply that trawler operators can approximately estimate prawn net drag from a function containing trawl twine area, towing speed and spread ratio. |
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