Movement of Spilled Oil at Sea

Waves at sea play an important role in the dispersion of the oil slick in the water column. In the oil literature, the breakup of oil into small droplets is referred to as "dispersion". The variation of concentration in space due to velocity variation in space is referred to as "spreading". Such a terminology is used in this work). While such a role has been acknowledged in many studies and empirical formulae were developed to account for wave intensity and breaking frequency, there is no work investigating the transport of oil droplets due to the direct effects of waves. Some authors investigated the indirect effects of waves through the formation of Langmuir cells. Currently wave tanks are being used to investigate dispersant effectiveness. Hence, from both theoretical and experimental (or operational) points of view, there is an emerging interest in understanding how waves affect dispersed oil droplets.

Water velocity distributions in a deep wave. (Period=2 sec, wavelength=6.18 m shown, steepness=0.10)

Example of how oil particles disperse in the open sea.

 

 

Click the image above to view an animation of droplet movement in open water due to the combined effects of currents and tide. This is merely for illustration, as the current due to tide is negligible at a depth of 1200 m. In the movie, one notes that the larger droplets rise to the surface while the small ones remain essentially at the same depth as the "source".