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Bouhoubeiny, Elkhadim; Germain, Gregory; Druault, Philippe. |
Flow field measurements past a fixed rigid cod-end structure and past a porous fishing net structure are conducted using Time-Resolved PIV method. The rigid cod-end is first used to characterize finely the wake flow. Proper Orthogonal Decomposition (POD) is then applied in order to extract the large scale energetic vortices of the flow from the measured velocity field. It is then observed that the first POD modes are associated to the Karman's type flow structure of vortex shedding. It is shown that the characteristics of the wake flow behind the rigid cod-end flow configuration compare quite well with previous ones obtained from bluff cylinder or sphere wake analyzes. Second, PIV measurements are performed around a non-rigid bottom trawl which is free to... |
Tipo: Text |
Palavras-chave: Fishing gear; PIV measurements; Vortex shedding; Proper Orthogonal Decomposition. |
Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00027/13820/11046.pdf |
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Druault, Philippe; Germain, Gregory. |
The coupled dynamics of the codend fluttering motion and its hydrodynamics behavior are investigated based on PIV measurements carried out around a 1/10 scaled model codend. The mean wake flow characteristics are firstly analyzed demonstrating the great effect of the codend motion. The differences in flow contour between fluttering motion and no-fluttering codend are highlighted by analyzing the classical mean characteristics of a body wake flow. In presence of fluttering motion, the classical results are recovered only if one considers the vertical extent of the codends oscillations as a reference length scale. Secondly, the frequency content of codend oscillations is analyzed and it is linked to the physical mechanisms. It is observed that the motion of... |
Tipo: Text |
Palavras-chave: PIV measurements; Fishing net structure; Wake hydrodynamics; Fluttering structure. |
Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00344/45503/45055.pdf |
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