Abstract: A 2D numerical model of oil spill accident involving oil particle was built on the basis of 2D tidal current model to investigate the spilled oil diffusion in the Yangtze River. Modifications were made to address the slow response of oil film expansion in horizontal diffusion mode and the insufficient response of oil spill. The model was applied to the simulation of oil spill accident in the reach between Zhenjiang and Yangzhou of the Yangtze River under assumed working conditions. Results demonstrated that the model could well reflect the characteristics of horizontal oil diffusion and the variation of oil spill thickness under the influences of flow field, wind field, self-weathering and complex terrain conditions. It could also accurately predict the persistent impact of oil spill diffusion on sensitive objects in the river channel. The research method offers powerful technical support for emergency treatment of oil spill accidents and water environment protection in the Yangtze River.

Key words: spilled oil pollution, oil particle model, horizontal diffusion features, numerical simulation, the Zhenjiang and Yangzhou reaches of Yangtze River