Numéro : 2088 - Year : 1989
Modelling of trawl: case of an axi-symetrical net
M.C MOREL, Allocataire de Recherche ,
D. MARICHAL, Professeur,Laboratoire d'Hydrodynamique Navale, URA 1217 CNRS, ENSM.Nantes.
M. MEILLAT, IFREMER Centre de Lorient.
Fishing trawl are hydrodynamlcally studied, in order to Improve their still very empirical design. The goal of the study is the prediction of the fishlng device shape versus the working conditions and. If possible, the drag force evaluation .
The coupling between hydrodynamic forces and net shape is very Intricate and not easy to describe. Therefore. In a first time. we propose the results of computatlons on nets of very simplified shape ( axi-symotrical configuration) .
This work Includes a theoretical as well as an experimental part. Both results are compared In order to Identify the hydrodynamic coefficients of the system. The iterative calculation takes into account for the hydrodynamic forces on the mesh leg and determines the equilibrium characteristics of the net (shape. holding forces. ...) .The comparison is concerned by the measured meridians and the measured towing strains. which have been carried out on models studied in the IFREMER-Lorient Circulating Water Channel. The measured models and the calculated models hold the same plan: no similarly Interferes.
The proposed numerical scheme allows us to find again the measured shape of an axi-symetrial net.