Author(s): X. Yan; A. Mohammadian

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Keywords: Numerical modeling; Vertical buoyant jets; Lateral confinement; Turbulence models

Abstract: Wastewater effluents that have a lower density than the ambient water body are often discharged into a marine environment in the form of turbulent buoyant jets. A submarine buoyant jet is often dynamically affected by boundaries, such as a jet from a submarine outfall pipeline that is laid in a dredged trench. Impact of wastewater effluents on environment is of significant concern, so the prediction of mixing of laterally confined turbulent buoyant jets is necessary for outfall design and environmental impact assessment. The near-field flow and mixing properties of vertical buoyant jets subjected to lateral confinement is studied numerically for different cases, including different confinement indexes (ratio of height to diameter of the confinement) and jet densimetric Froude numbers (ratio of inertia to buoyancy force). The performance of different turbulence models are investigated, such as the standard k-ε turbulence model and buoyancy-modified k-ε model (GGDH). The simulated results are compared to previous and the present experimental data. It is found that the buoyancy-modified turbulence models can produce better results than the standard turbulence models. Furthermore, various numerical experiments are conducted, and simple relations for predicting the flow and mixing characteristics of a laterally confined jet are provided.

DOI:

Year: 2016