Underwater spreading and surface drifting of oil spilled from a submarine pipeline under the combined action of wave and current

Tremendous economic loss and environmental damages are caused by oil-spilling accidents in sea. Accurate prediction of the underwater spreading and surface drifting of oil spills is important for the emergency response. In the present study, numerical investigation on the underwater spread and surface drift of oil spilled from a submarine pipeline under the combined action of wave and current was carried out to examine the effects of physical ocean environment, leaking flux and spilled oil density and viscosity. Reynolds-Averaged-Navier-Stokes (RANS) equations, realizable k-ε turbulence model and volume of fluid (VOF) model are employed to describe the multiphase flow, and velocity-boundary wave-making technique combined with the sponge layer damping absorber technique realizes the numerical wave flume. Oil spill experiments were conducted to validate the numerical model. The calculation results indicate that compared with the environmental conditions of still water, only current and only wave, a larger scope of underwater spreading and relatively slower rising rate and relatively faster drifting rate of oil droplets are observed under the combined action of wave and current. The leaking flux affects the floating time and dispersion concentration, while the ocean environment affects the horizontal migration and surface drifting. Under the specific conditions of present work, oil density has obvious effect on the underwater spread but limited effect on the surface drifting, while oil viscosity has little effect on both the two processes.