The simulation of interaction of nonlinear waves with structures has been investigated by several investigators adopting Boundary element Method (BEM) and Finite Element Method (FEM). In handling complex geometries using FEM, simulation with unstructured mesh is required. The two options that are available in handling unstructured mesh are: regenerating the mesh for each time step, requiring a higher computational cost and the mesh moving procedure widely used in solid mechanics. In this paper, the application of two different spring analogies (Vertex and Segment methods) on the simulation of nonlinear free surface waves and its interaction with a submerged structure is reported. The numerical method has been extended to generate solitary waves, the results of which have been compared with laboratory tests that include the wave kinematics using PIV measurements.
The simulation of nonlinear waves based on time-domain has gained tremendous momentum due to the recent improvements in numerical techniques and computational power. This has been modelled by using BEM and FEM. In modeling complex geometry or for the simulation in the presence of floating bodies, one needs to resort to an unstructured mesh simulation for FEM based codes. In the case of structured mesh, the regeneration of mesh at every time step is evaluated based on the new free surface nodes with the vertical elevation calculated using a simple formula as proposed by Wu and Eatock Taylor (1994). The computation is inexpensive and thus regeneration of mesh nodes can be done with ease. In the case of unstructured mesh, one has to resort to the external mesh generation code (First approach) or commercial CFD mesh generators (second approach). While using the first approach, regeneration of mesh is possible at every time step by invoking the external code from the source code, whereas, in the second approach, it is not possible to update at each of the time step automatically.
