A CFD solution of oil spill problems

Abstract

Over the past three decades simplified empirical formulae contributed greatly in a rapid evaluation of the oil slick spreading and drifting. Modern oil spill models can utilise more accurate and physically relevant mathematical formulations. The suggested Multiphase Oil Spill Model is an attempt to take advantage of recent developments in areas of Computational Fluid Dynamics (CFD) and Environmental Modelling. A consistent Eulerian approach is applied across the model, the slick thickness is computed using layer-averaged Navier–Stokes equations, and the advection–diffusion equation is employed to simulate oil dynamics in the water column. To match the observed balance between advection, diffusion and spreading phenomena, a high-order accuracy numerical scheme is developed. Vertical dynamics of oil droplets plays a major role in oil mass exchange between the slick and the water column. Oil mixing by breaking waves is parameterised using newly developed kinetic equations. Majority parameters of oil, water column and breaking waves are conveniently combined into a single “mixing factor”, quantifying partitioning of oil between the slick and the water column. The model is able to predict rate of oil entrainment for different scenarios of dispersant application with respect to the storm intensity and duration. Governing equations are verified using test cases, data and other models, and subsequently applied to Singapore Strait to simulate a hypothetical oil spill.