THE MOVEMENT OF OIL AT SEA DUE TO IRREGULAR WAVES

摘要

Our previous work investigated the transport of oil under regular waves at sea. This work considered irregular waves represented by a JONSWAP spectrum, which is a more realistic situation. Particle tracking was used in a Monte Carlo framework to evaluate the combined effects of wave kinematics and turbulent diffusion on the transport of oil droplets at sea. The centroids, variance and spreading coefficients of oil spills with various wave parameters were found in this study. Turbulent diffusion was assumed to be velocity-dependent, and an empirical formulation adopted from subsurface hydrology was adopted. Five hundred neutrally-buoyant oil "particles" were placed at the water surface and tracked for 1 hour. The vertical movement of the plume appeared to be comparable to the significant wave height (about one meter herein), and to decrease with depth. The increase in wind fetch caused an increase in transport and spreading of the plume. The results found in this study can be used by spill responders as a first approximation to the spread of a dispersed oil spill, or can be used as parameters as part of a more complex code used to model oil spills.