Computational modelling of free surface flows for offshore application

In this paper we discuss the fundamentals of techniques that can be applied to numerically model fluid flows with interfaces. Application of these methods is especially relevant to the impact of waves on offshore structures and ships, but they can more generally be used to model any situation including the effect of tsunamis on on-shore structures, the release of large volumes of gas from undersea pipelines etc. The first method is the traditional Volume-of-Fluid (VOF) method that has been used quite extensively in the area of offshore hydrodynamics. We also introduce a less common technique, Smoothed Particle Hydrodynamics (SPH), originally developed for compressible gas flows, but more recently being applied to a wide variety of applications where VOF techniques are traditionally used. The advantages of SPH are highlighted, and examples of its application presented.