Turbulent Mixing in Transverse Jets
- Creators
- Shan, Jerry
- Dimotakis, Paul
Abstract
Turbulent mixing is studied in liquid-phase transverse jets. Jet-fluid concentration fields were measured using laser-induced fluorescence and digital-imaging techniques, for jets in the Reynolds number range 1000 <= Re <= 20,000, at a jet-to-freestream velocity ratio of 10. Analysis of the measured scalar fields indicates that turbulent mixing is Reynolds-number dependent, as manifest in the evolving probability density functions of jet-fluid concentration. Enhanced homogenization is found with increasing Reynolds number. Turbulent mixing is also seen to be flow dependent, based on differences between jets discharging into a crossflow and jets into a quiescent reservoir. A novel technique for whole-field measurement of scalar increments was used to study the distribution of difference (scalar increments) of the scalar field. These scalar increments are found to tend toward exponential-tailed distributions with decreasing separation distance. Finally, the scalar field is found to be anisotropic, particularly at small length scales. This is seen in power spectra, directional scalar microscales, and directional PDFs of scalar increments. The local anisotropy of the scalar field is explained in terms of the global dynamics and large-scale strain field of the transverse jet.
Attached Files
Published - ppr137_CaltechGalcitFM2001.006.pdf
Files
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Additional details
- Eprint ID
- 25812
- Resolver ID
- CaltechGALCITFM:2001.006
- Created
-
2001-10-18Created from EPrint's datestamp field
- Updated
-
2021-11-22Created from EPrint's last_modified field
- Caltech groups
- Graduate Aeronautical Laboratories (Fluid Mechanics), GALCIT
- Other Numbering System Name
- GALCIT Report FM
- Other Numbering System Identifier
- 2001.006