3-D Oil spill modelling. Natural dispersion and the spreading of oil-water emulsions in the water column

A 3-D hybrid turbulence model, simulating the transport and fate of oil spills in various waters, is
used to evaluate the influence of natural dispersion on the spreading of water-in-oil emulsions
formed in the water column. The model combines the Navier-Stokes equations for two-phase flows,
the RNG k-ε submodel, and parameterized expressions of the basic processes affecting the fate of
oil spills. The model also considers the presence of waves, the wind- and wave- induced surface
drifts, and the influence of surface wave breaking on the oil spills.
Using a stochastic probability model of breaking waves, the loss of surface wave energy into
turbulence, due to breaking, is derived and the rate of natural dispersion of oil mass and that of oilwater
emulsions formed in the water column is evaluated, under a variety of sea state conditions.
Results in the form of oil concentration profiles with depth, graphs showing the variation of the
fraction of water (mass) absorbed by the dispersed oil, at various depths and times, as well as
graphs showing the oil mass balance, at the sea surface, at various times are compared with
counterpart profiles, and graphs obtained from the literature, and useful conclusions are drawn.