The smoothed particle hydrodynamics (SPH) method is applied to study the oil film diffusion in the water. By modifying the SPH equations of fluid dynamics, the multiphase flow SPH equations are obtained to establish the computational oil film diffusion model. By discussing three kinds of particle pairing schemes in the calculation of oil particle density, the redistribution mode of particle density is determined. The diffusion process of oil film is simulated, the effects of oil viscosity coefficient and particle density on oil film diffusion are analyzed, and the distribution of local pressure near oil particles in the process of oil film spreading is calculated. Finally, the calculated value of the oil film expansion diameter is compared with two other numerical models, and the calculated result shows a high coherence with the others.

This paper presents a simulation method for oil spills in a multi-island area. The simulation considers three parts, which consist of(1)the spreading of an oil slick on its edge as well as the diffusion and drift under dynamic actions,(2)the evaporation and spreading thickness of an oil slick in its interior, and(3)the adsorption and emulsification near shorelines and islands. The Euler-Lagrange method is adopted to track the spill location and particles positions on the edge of oil slicks. A mathematical model of marine oil spills is established for the Luanjiakou District of the Port of Yantai. The flow field verification shows that the BIAS of tidal level, flow velocity, and flow direction is below ±10 cm, 0.11 m/s, and ±2°, respectively, and the oil spill verification captures satisfactory results. Hence, the proposed model could reproduce the oil spill process in this region. Then, we simulate oil spills under various operating conditions. It is concluded that the transport of oil slicks is mainly influenced by flood/ebb currents, whereas the wind plays a major role in the drift and thickness of oil slicks. The study provides an important reference to controlling and handling of accidental oil spills.

This work aims at investigating the impact of different tidal turbine locations on hydrodynamics in near-field and far-field flow; thus, three- and two-dimensional (3- & 2-D) models were exploited in combination and applied in a case study of Putuo-Hulu Islands’ tidal farm. We present a method for the simplification of tidal turbine which, based on the energy equation, determines turbine’s equivalent roughness by calculating resistance loss in flow passage. A 3-D turbine model of near-field flow in the frame of Computational Fluid Dynamics was constructed, and the flow velocity distributions in 7 combinations of “impeller rotating speed - inflow velocity” were simulated. Also a 2-D tidal model of far-field flow was established, and Finite Element Method was adopted to solve the 2-D shallow water circulation equations; thus, the impact of tidal turbine could be simulated by utilizing different location’s compositive roughness. The results show that the impact of turbine location on hydrodynamics is depending on the open degree of sea area, channel trend, and bathymetric and geographic features and that the farther distance from the turbine, the less impact on the flow field. Overall, the impact of turbine location on far-field flow is not significant, and the flow velocity varies below 8% relative to the velocity prior to turbine installation.