Liu Bie Ju Centre for Mathematical Sciences
City University of Hong Kong
Mathematical Analysis and its Applications
Colloquium

Organized by Prof. Philippe G. Ciarlet and Prof. Roderick Wong

Mathematical Modeling and Numerical Simulations of Cod-End
Fish Nets and of the Surrounding Flow

by
Prof Roger LEWANDOWSKI
University of Rennes - France

Date : November 9, 2005 (Wednesday)
Time : 5:15 pm to 6:15 pm
Venue : Room 6605 (Faculty Conference Room)
Blue Zone, Level 6, Academic Building
City University of Hong Kong

Abstract: The efforts made by the fishing industry to achieve a sustainable activity require an improvement of the knowledge of the behavior of the fishing gear at sea, especially that of the netting , as well as of the flow inside and outside. A cod-end fish net is first modelled by a discrete finite network. The nonlinear elastic energy for such a structure is defined and studied. Numerical simulations  of the equilibrium state are performed by minimizing the total energy. We also study the flow around a rigid net. The flow being turbulent, we use a first-order closure model of turbulence, which we adapt to the present case. The model uses a fictitous domain decomposition and the information related to the net is inserted in the equations by penalization terms thanks to Brinckman's law.  The boundary conditions are the so-called «ghost conditions» outside the computation box, so as to avoid eddy reflections in numerical simulations. We show that the resulting system of equations has a weak solution. Finally, we present numerical results and compare them with experimental data.

* Tea, coffee and cookies will be provided at the Faculty Common Room in B6501 before the colloquium from 5:00 p.m. to 5:15 p.m. Please come and join us!

** All interested are welcome **

For enquiry: 2788-9816

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