Efficiency of Jet Mixing of Temperature‐Stratified Water

Abstract

This paper deals with artificial mixing of naturally temperature‐stratified water bodies, such as lakes, reservoirs, and ponds, by selective withdrawal and jet reinjection at a different depth. The effects of jet orientation and jet momentum on mixing processes and efficiency are investigated. A one‐dimensional simulation model, previously verified against experimental data for horizontal jets, is applied to experimental data for vertical jets in this paper. It is found that destratification by a vertical jet is slightly more efficient than by a horizontal jet. Destratification is measured by a stability parameter. More than 80% mixing is achieved when 20% or more of the water volume between withdrawal and reinjection points is recycled. Low‐momentum jets are found more efficient than high‐momentum jets. Efficiency was measured in terms of energy demand relative to change in potential energy. Basins of rectangular or parabolic shape are investigated.