Dynamics of Jets in Two‐Layer Stratified Fluids

Abstract

The results of experiments on nonbuoyant jets discharged horizontally into the lower layer of a stagnant two layer stratified fluid are presented. The stratification consists of a well‐mixed upper layer separated by a finite density jump from a linearly stratified lower layer. Similar flows occur in pumped‐storage reservoirs and Ocean Thermal Energy Conversion (OTEC) discharges in the ocean. The flow consists of a jet which entrains ambient fluid selectively from a layer of finite thickness before collapsing vertically and spreading sideways and forwards as a horizontal density current. Analysis is primarily based on dimensional analysis and length scale arguments, and results are presented to predict whether entrainment from the upper layer occurs, the widths and locations of the entrained flow and depth of the ambient mixed by the jet, the total jet volume flux, and the collapsed layer thickness. The results are applied to an OTEC design; predicted values of collapsed layer thickness, distance to collapse, and terminal dilution were in reasonable agreement with previously measured values.