| Simulations of overturning waves have been a challenging objective of many research efforts. To date, only one successful approach, the boundary integral scheme, exists. This method, which is based on the assumption of irrotationality, does not have the ability to describe many fluid phenomena of great industrial and academic interest, in which rotationality and/or viscosity is of significance. A new method which can handle such cases is needed.; In this thesis, a robust and efficient algorithm for unstructured meshes has been developed for steady and time-dependent computations of nonlinear free surface flow which is capable of treating breaking waves. The method uses the generalized artificial compressibility approach to couple the incompressible Euler equations and continuity equation in a hyperbolic manner, which allows several techniques for convergence acceleration to be implemented. Front tracking techniques, which include Lagrangian and Eulerian formulations, are utilized to describe the free surface location. The proposed generalized Eulerian formulation is proved to be more advantageous. Two mesh-adaptive strategies are used, namely the spring method and the adaptation method.The devised adaption method is based on the Delaunay triangulation method and will yield a more accurate result, especially for an unsteady calculation.; The method is validated versus analytical solutions for a solitary wave. Comparisons with experimental data are made for flows around a NACA 0012 hydrofoil placed in an initially calm sea and for a plunging breaker. |
