Abstract
A square jet with four vortex-generating tabs has been investigated by flow visualizations using Laser Induced Fluorescence technique and by velocity measurements using a Laser Doppler Anemometer. The tabs, which are triangular in shape, are tilted into the jet at either ? = 45° or 135° with respect to the main flow direction. The flow visualization results illustrate that with the addition of fourtabs, the cross-section of the jet core is bifurcated into a four-"finger" structure. For ? = 135° in particular, there is an additional "mushroom" structure between two neighboring fingers. Secondary velocities show that a pair of streamwise vortices is generated by each tab. These streamwise vortices tend to spread the jet fluids "outward" along the diagonal direction, resulting in a four-finger structure of the jet core. In the case of ? = 135°, the additional third pair of streamwise vortices previously proposed by other researchers is confirmed in the present study, which is responsible for the unique mushroom structure. The tab effects on the jet spreading and on the axis-switching phenomenon are also discussed. © 2003 Published by The Japan Society of Fluid Mechanics and Elsevier Science B.V. All rights reserved.
| Original language | English |
|---|---|
| Pages (from-to) | 99-117 |
| Number of pages | 19 |
| Journal | Fluid Dynamics Research |
| Volume | 32 |
| Issue number | 3 |
| DOIs | |
| Publication status | Published - 1 Jan 2003 |
| Externally published | Yes |
Keywords
- Laser Doppler Anemometer
- Laser Induced Fluorescence
- Square jet
- Vortex-generating tab
ASJC Scopus subject areas
- Mechanical Engineering
- Physics and Astronomy(all)
- Fluid Flow and Transfer Processes