Turbulent Flows with Heat and Mass Transport in Open Channels

Two approaches are tested and evaluated to reduce the effort and time required for computation of turbulent flows that plunge and travel as density currents in open channels. These approaches include: (1) Boussinesq approximation when solving the heat transport equation instead of describing the density as a function of temperature, and (2) equivalent excess density approach which combines the two equations of heat transfer and dissolved solids transport in one equation. The computational fluid dynamics solver FLUENT is utilized for testing and evaluation of such methods by applying to a negatively-buoyant flow in a diverging channel. The numerical results show that both the Boussienesq approximation and the equivalent excess density approaches give reasonably accurate solutions and in the same time reduce the computing time.