Numerical determination of oil spill areas in water bodies

This paper presents a new model to predict the evolution of oil spills based on the numerical solution of transport and mass conservation equations. With this model it is possible to estimate the area, geometry and trajectory of an oil spill. The model is capable of considering changes in main modeling parameters, such as hydrodynamic and meteorological conditions, bathymetry, physical processes in oil transformation, and changes in oil properties. A method was devised to estimate the evolution of the dark area of the slick based on the sum of the areas occupied by the oil on the computational grid mesh and a given normalized concentration limit. In the implementation of the model, the equations are discretized using the finite volume method, while the resolution of the equations is done via the SIMPLEST method, included in the PHOENICS code. The procedure used to define the conditions for a spillage simulation produced a good fit compared with the experimental results measured by Lehr et al. (1984a, 1984b) for the dark area of the slick in both the growth and dispersion phases. The main advantage of this model over other, more simplistic, spill models is that it can predict the evolution of the area of the slick taking into consideration the changes that can be wrought by natural obstacles, such as bathymetry, by maritime installations and by flow barriers placed to contain the spillage as well as changes in meteorological and hydrological conditions.