Dissolution of oil in water in the viscous-gravity stage of oil spreading

Spreading of oil on water significantly enhances the water-oil interfacial area. The increase in the interfacial area and the hydrodynamics induced by the viscous oil in the water column underneath the oil affect the dynamics of dissolution of oil in water. The mass transfer dynamics is investigated in the viscous-gravity spreading regime where gravity, promoting spreading, is resisted by the viscous force exerted by the water on the spreading oil. Both unidirectional and axisymmetric spreading cases are considered. A model is developed using an integral boundary layer approach based on fundamentals. The similarity solution provides the time dependent average mass transfer coefficient, concentration boundary layer thickness, and mass transfer coefficient profiles as functions of Schmidt number, geometry and time. Taking into account the typical large oil to water viscosity ratio, the results are discussed based on physical grounds in the light of boundary layer theory to interpret the difference in the asymptotic behavior of the solution near, and sufficiently far from the leading edge of the oil spill.

Automated summary

The spreading of oil on water increases the interfacial area between the two phases and is affected by the hydrodynamics induced by the viscous oil in the water column. This study investigates the mass transfer dynamics of oil dissolution in water in the viscous-gravity spreading regime. The results provide insights into the behavior of oil spills near and far from the leading edge of the spill.