Numerical simulation of vertical buoyant wall jet discharged into a linearly stratified environment

Abstract

Results are presented from a numerical simulation to investigate the vertical buoyant wall jet discharged into a linearly stratified environment. A tracer transport model considering density variation is implemented. The standard k-ε model with the buoyancy effect is used to simulate the evolution of the buoyant jet in a stratified environment. Results show that the maximum jet velocity trend along vertical direction has two regions: acceleration region and deceleration region. In the deceleration region, jet velocity is reduced by the mixing taking place between jet fluid and ambient lighter fluid. Jet velocity is further decelerated by the upwards buoyant force when ambient fluid density is larger than jet fluid density. The normalized peak value of the cross sectional maximum jet velocity decreases with λ (the ratio between the characteristic momentum length and the buoyancy length). When λ<1, the dimensionless maximum penetration distance (normalized by the characteristic buoyancy length) does not vary much and has a value between 4.0 and 5.0, while it increases with increasing λ for λ≥1. General good agreements between the simulations and measurements are obtained, indicating that the model can be successfully applied to investigate the mixing of buoyant jet with ambient linearly stratified fluid.