Numéro : 1955 - Year : 1984
Study of the wave action on floating structures by the boundary elements method comparison with the finite elements method.
S. GRILLI, Ingénieur Civil, Aspirant FNRS L.H.C.H. Université de Liège
In this paper, the boundary elements method is applied to the linearized tridimensional problem of the wave action on floating structures. The theoretical formulations developed as usual, lead to the diffraction-radiation problem equations which we use the Petrov-Galerkin minimization principle for.
The choice of the ponderation functions as particular solutions of a Dirac equation, allows to eliminate the volume integration, and to resolve the problem on the boundary.
This last is completely discretized by boundary elements of different types, (linear, quadratic, one or two dimensions) which allow, for instance, the treatment of finite depth or any bottom geometry cases.
The radiation condition is the Sommerfeld condition, first applied at finite distance, then, it's improved by the use of orthogonal eigenfunction expansions representing better the infinite.
Different numerical integration methods of the singularities are compared with their influences on the results accuracy.
At last, we present a numerical comparison in a simple bidimensional case, between the finite element and the boundary element solutions.