Instability and Turbulence in a Stratified Shear Layer
Abstract
The results of an experimental investigation of shear instability and turbulent mixing in a stratified fluid are presented. Two parallel streams of water, moving at different velocities and having different densities (salinities) are produced in an open channel. Dye and shadowgraph techniques are used to visualize the flow, and quantitative measurements of velocity and density are made with hot films and conductivity probes. Two modes of instability are possible, depending upon the initial value of the Richardson number. For small Richardson numbers, large scale vortices are observed Initially, as in the unstratified case, but they are eventually destroyed by the stable stratification. Flow field measurements give a maximum thickness of the mixing region which agree with recent theoretical predictions. The amount of permanent vertical solute transport produced by the turbulent event varies inversely with the Initial Richardson number. As the Initial Richardson number increases, a transition to interfacial wave-breaking occurs which has no unstratified counterpart. These waves eventually decay, and the net effect on the vertical solute transport becomes vanishingly small at sufficiently high initial Richardson numbers.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1976
- Accession Number
- ADA026634
Entities
People
- C. G. Koop
Organizations
- University of Southern California