Author(s): Adam M. Witt; John S. Gulliver
Keywords: Aerated flows; air–water interface interactions; bubble dynamics; flow–structure interactions; gas transfer; hydraulic jump; water quality
Abstract: An improved model for predicting oxygen transfer efficiency at gated sills is presented. An analysis of field measurements from eight gated sill structures is used to develop a dimensionless relationship between inflow conditions, dam geometry and oxygen transfer efficiency. The oxygen transfer coefficient is estimated from scaled formulations of the liquid film coefficient, mean bubble diameter, air entrainment rate and turbulent energy dissipation rate. The model is validated with additional field measurements adjusted for temperature and effective saturation concentration. A design parameter for gated sill dams is introduced giving a relationship between gate opening and oxygen transfer efficiency. Improved prediction of oxygen transfer in the field is a tool that can be used to successfully operate gated structures to meet oxygen concentration requirements and to assist in the design of remediation technologies.