Buoyant mixing of unstably stratified fluids in a vertical square tube

Michael D Patterson, C P Caulfield, S B Dalziel

Research output: Chapter or section in a book/report/conference proceedingChapter or section


Quantitative time dependent measurements of irreversible mixing caused by the development of Rayleigh-Taylor instability on an initially unstable two-layer stratification of miscible fluids are taken from a series of laboratory experiments. The experiments are conducted by overturning a stable stratification in a high-aspect ratio tank with square cross-section, and are observed until the flow is quiescent.

Using a light attenuation technique we obtain detailed time-dependent measures of the irreversible mixing, and its efficiency during flow evolution. We find that the flow passes through a number of distinct phases, beginning with classical t2 grow of the instability before a rapid (but gradually slowing) growth of the instability along the entire length of the tube. The still statically unstable mean stratification continues to drive turbulent mixing along the tube, ultimately leading to a weakly stably stratified final state with a gradual exponential decay of the remaining disturbances.
Original languageEnglish
Title of host publicationProceedings of the 6th International Symposium on Stratified Flows
EditorsG Ivery
Number of pages6
Publication statusPublished - 2006
Event6th International Symposium on Stratified Flows - Perth, Australia
Duration: 11 Dec 200614 Dec 2006


Conference6th International Symposium on Stratified Flows


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