Scalar flux modeling of solute transport in open channel flows: Numerical tests and effects of secondary currents

Abstract

Numerical experiments involving various algebraic scalar flux models for solute transport in open channel flows are presented. Five algebraic scalar flux models including these of Daly and Harlow, Abe and Suga, Suga and Abe, Sommer and So, and Wikstrom et al. are tested. For the flow computation, a Reynolds stress model is used. The models are applied to laboratory experiments of solute transport in rectangular and compound open channel flows. The performance of each model is evaluated both qualitatively and quantitatively. It is found that Daly and Harlow's model, although simple, predicts the solute transport most accurately. Further, with reference to the simulation results, the roles of the Reynolds fluxes and secondary currents in the solute transport equation are investigated. It is found that the Reynolds fluxes and secondary currents reduce and move the peak concentration, respectively.

Keywords:

• Open channel flow
• Reynolds flux
• Scalar flux model
• Secondary currents
• Solute transport