Study of the manoeuvrability and security of a trawl gear

A complete method is presented for determining the static and dynamic behaviour of a fishing gear. The net, which is very flexible, is modelised by a set of rigid bars. The hydrodynamic forces, applied to each bar, are determined by combining and generalizing the Landweber and Morison hypothesis. A CFD method is used to calculate the forces on trawl doors. The fundamental principle of dynamics is completed with length equations expressing the elasticity of the bars. It leads to a set of second order non-linear differential equations, which is solved using a Runge-Kutta method. We will now present a few examples of the various applications of our works: the study of the trawl gear equilibrium in a uniform flow, an example of manoeuvrability (gyration of the trawl gear) and an application to security with the simulation of an obstruction