A lattice Boltizmann method for submarine outfalls: the mixing zone calculation

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Zhuangming Zhao, Zhenren Guo, Xiao Zhao, Haijun Peng

Tuesday 30 june 2015

17:48 - 17:51h at Europe 1 & 2 (level 0)

Themes: (T) Water engineering, (ST) Computational methods, Poster pitches

Parallel session: Poster pitches: 7E. Engineering - Computional

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Long submarine outfalls with a multiport diffuser are an efficient discharge device avoiding pollutant accumulation and collapse of ecosystems by dispersing the treated effluents. The mixing zone of the effluents, within which the concentration of one or more pollutants may exceed the relevant environmental quality standards, is quite important for the outfalls. To accurately simulate the mixing zone, a new lattice Boltzmann method for the pollutant discharge from the submarine outfalls is developed. It based on the combination of the lattice Boltzmann equation (LBE) and the kinematic boundary condition (KBC) method to simulate the free surface. In the method, the flow field is modeled by LBE, whereas the free surface is explicitly tracked by the local height function, which is calculated by the KBC method. Interpolation-supplemented lattice Boltzmann (ISLB) method is introduced, which enables our approach to be applied on arbitrary, nonuniform mesh grids. The turbulence model was applied to meat the requirement of turbulent flow. Moreover, a lattice Boltzmann model for the advection and dispersion of pollutant is used. Several cases are simulated respectively to validate the proposed method. KEY WORDS: lattice Boltzmann equation (LBE), kinematic boundary condition (KBC), free surface, non-hydrostatic pressure, multi-relaxation-time (MRT) model