SIMPLIFIED MODELS TO PREDICT THE BREAKUP OF OIL ON ROUGH SEAS

Abstract

ABSTRACT This study attempts to integrate existing theoretical models and experimental information on the behavior of oil spills in the ocean into a unified, sequential calculation procedure to predict the breakup of oil on rough seas. Major consideration has been given to developing the least sophisticated calculation procedures that maintain a reasonable description of the totality of the physical process. The principal phenomena included in the prediction of the spill behavior are as follows: combined spreading and evaporation; slick-sea interaction and formation of oil droplets; dispersion of droplets in the water column; and, finally, the formation and dispersion of slicklets caused by turbulence in the ocean. A multicomponent spreading-evaporation model was developed to predict the area, average density, and mass loss because of evaporation from the slick as a function of time for various environmental conditions. On the basis of the well-known Pierson-Moskowitz spectrum for a fully developed sea, models were developed to predict the size of oil droplets and their distribution in the water column. A horizontal diffusion model was developed on the basis of several experimental observations to determine the dispersion of slicklets and predict the total contaminated ocean surface area as a function of time. The integrated model is computerized and has been exercised for four different types of oils, namely, light crude, heavy crude, fuel oil No. 2, and fuel oil No. 6.