THE UNDERWATER TRAJECTORY BEHAVIOUR OF HEAVY OIL JET IN CROSS-FLOW FROM A BROKEN SURFACE PIPELINE

Abstract

Oil spill occurrences continue to raise varying questions and concerns about their impact on and behaviour in the marine environment as they have the potential to cause unfavourable environmental, economic and social impacts. Understanding the behaviour of oil interactions with the ocean and nearby coastal environments is crucial in maintaining a reasonable relationship between relevant stakeholders. For this purpose, oil spill numerical models are useful for predicting the movement and distribution of oil in any receiving marine environment. As a first attempt, this paper presents a very crude oil plume model to simulate the underwater behaviour of a heavy crude oil which originates from an injection point source protruding the water surface discharging heavy oil into a receiving water body of shallow water depth. Most of the existing surface oil spill models do not cater for spills that initially behave as a jet at the water surface which is an essential feature of this hypothetical oil spill scenario. The study sets a specific focus on simulating the underwater suspension and horizontal movement of an oil plume originating from a spill initially behaving as a positively buoyant jet. The model is based on a two-dimensional modified form of the classical Navier-Stokes equations and discretized using the Projection method. The model is applied in a rectangular domain with suitable boundary conditions and parameterizations to observe the underwater oil trajectory behaviour. The model is verified using a benchmark fluid flow problem and its results show reasonable relationship of specific gravity with depth. The ultimate contribution of the study can provide insights necessary for oil spill cleanup decisions as oil behaviour of this nature may pollute the underlying water.