Computer Simulation of Violent Wave Overtopping
Specifically my work on the development of Numerical Models for the simulation of violent wave overtopping has been funded through several EPSRC and one EU grant. This work has entailed the development of Advanced Numerical Models in close co-operation with both physical modellers and design engineers. A current EPSRC grant (on which I am the Principal Investigator) is attempting to implement the solver on a national High Performance Computing facility in order to allow the simulation of the full 1000 wave duration of realistic storms. In many cases detailed knowledge and understanding of the overtopping processes requires a combination of numerical simulation and physical modelling. As a result much of this work has been done in close collaboration with others especially Bruce [IES, Edinburgh], Muller [Southampton], Allsop [HR-Wallingford], Causon [Manchester Met], Mingham [Manchester Met], Troch [Gent, Belgium] and Watanabe [Hokkaido, Japan].
Cartesian Cut Cell Methods
One of the first tasks to be faced in computational fluid dynamics (CFD) is the generation of a suitable computational mesh. Although a variety of mesh generation techniques are available, the generation of a suitable mesh for complex, multi-element, geometries is still a complex and tedious task. The two, traditional, approaches are: the use of a structured body-fitted mesh utilising a multi-block structure, in which the blocks may overlap and the use of a completely unstructured body-fitted mesh. Both of these approaches require significant efforts in mesh generation to ensure that the generated mesh is of sufficient quality to both accurately represent the geometry and provide a high quality solution. Even in cases where a detailed description of the geometry is available from a CAD system, mesh generation can still be a complex task, requiring much more time to generate the grid than to simulate the fluid flow. An alternative approach is the use of Cartesian cut cells. This conceptually simple approach "cuts" solid bodies out of a background Cartesian mesh. Although originally developed for potential flow, the method has been successfully applied to the Euler equations in two and three space dimensions, to the shallow water equations (SWE) and extended to deal with low speed incompressible flows and flows involving moving material interfaces. The technique is also particularly suited to problems involving moving solid boundaries whose motion is either driven externally or responding to the local fluid motion.