Immiscible Rayleigh-Taylor Turbulence: Implications for Bacterial Degradation in Oil Spills

Immiscible flows at density interfaces are central to many environmental processes, from oil spills in the ocean to contaminant transport in groundwater. A canonical case is the immiscible Rayleigh–Taylor turbulence (IRTT), which develops when heavier water initially overlays lighter oil, such as in deep water oil spills. Unlike classical miscible RT turbulence, where a single mixed phase is generated, IRTT involves the continual deformation, stretching, and fragmentation of fluid interfaces. In this seminar, I will present recent work on the fundamental mechanisms of IRTT and their implications for oil spills. Using laboratory experiments, direct numerical simulations, and theoretical modeling, we quantify how buoyancy driven turbulence fragments the oil-water interface. Our results show that the evolution of the interface follows distinct scaling regimes compared to miscible turbulence, with the development of a capillary wave turbulence cascade originating at the Hinze scale and sustained by Kolmogorov turbulence in the bulk. From an environmental perspective, these findings provide a mechanistic bridge between hydrodynamics and biodegradation, as the surface area made available by IRTT sets the rate at which bacteria can colonize and metabolize hydrocarbons. We demonstrate this link quantitatively, showing that, neglecting the eƯect of turbulence, can lead to an overestimation of the degradation rate by up to 400%.