Turbulent Structure of Rotating Oil Plumes under Stratification

The overall fate and transport of oil after a deep-water blowout depends heavily on the vertical distribution of effluent, set predominantly by turbulent plume dynamics. Of primary modeling importance is understanding how long effluent parcels remain in the water column, what fraction reach the surface and what is the surface expression of individual effluent constituents. Previous laboratory experiments and numerical simulations of thermal and gas bubble plumes have shown, that system rotation significantly alters plume behavior even at oceanographic Rossby numbers. In the current study, we turn our attention to modelling liquid-liquid mixtures of water and oil allowing for weak slip of the oil phase relative to water. High-fidelity turbulence simulations employing high-order spectral-element methods (SEM) and a computational domain that includes fully turbulent effluent input from a resolved pipe, are used to study the evolving structure of the oil plumes in the presence of background stratification and rotation. The multiphase oil plume is modeled using a standard mixture model for the liquid phases in a Boussinesq, Eulerian-Eulerian framework while incorporating a non-linear model for the effective phase slip. We concentrate on the effects of varying both the Rossby number and slip speed on the overall level of sub-surface oil trapping of and on changing both the number and thickness of the multiple intrusion layers formed.