A fully Eulerian two-layer model for the simulation of oil spills spreading over coastal flows

Nowadays, the vast majority of coastal oil spill simulation models are based on Lagrangian methods focused on particle tracking algorithms to represent the oil slick fate. In this work, a fully Eulerian numerical model for the simulation of such environmentally significant disaster is implemented by means of a two-dimensional two-layer shallow water model. A very thin oil layer over a thicker water layer is considered in order to neglect the pressure term that the oil layer exerts over the water. Friction terms between layers are responsible for the layers coupling so that the oil layer flows over a moving water volume. To complete this dynamic model, the temperature transport and evolution under heat exchange for the oil upper layer is considered and the weathering process of evaporation is included. The numerical solution adopted is based on a finite volume upwind scheme with a Roe solver for both oil and water layers. Special care has been taken on the numerical treatment of the two-layer wet-dry boundaries (oil–water–land) and friction terms, since the objective of the model is to compute the oil slick front advancing near the coast.