1.4.3. Mesh generation

Mesh requirements are different depending on wether, frequency or time domain analysis are used. Frequency domain analysis just require a body boundary mesh consistent on quadrilateral elements. Hence, it usually suffices to provide a global mesh size and mesh transition, since SeaFEM automatically sets the type of element required. Complicated geometries may require additional assignment of local mesh sizes.

On the other hand, in order to generate a good quality mesh for time domain analysis, it is advised to the user to follow these recommendations:

• The mesh size at the body and free surface in the analysis area must be small enough so that the geometry and the smaller wave can be represented accurately. The mesh size should be no larger than one fifth of the smallest wave length. Recommended value, at least, one tenth.

• Mesh size at the outlet should be no larger than one fifth of the distance to the reference point.

• Mesh size at the portion of the bottom located right below the body should be no larger than one fifth of the computational depth. Recommended value is one tenth when the computational depth is at least as large as the maximum wave length. Otherwise, the smaller the computational depth, the smaller the mesh size.

• Mesh size transition should be reasonable smooth around the analysis area.

• Lines should be assigned a mesh size corresponding to the minimum size assigned to the surfaces they belong to.

• Points should be assigned a mesh size corresponding to the minimum size assigned to the lines they belong to.