Hostname: page-component-78c5997874-xbtfd Total loading time: 0 Render date: 2024-11-11T04:14:19.693Z Has data issue: false hasContentIssue false
  • English
  • Français

Comparisons of Flow and Mixing Characteristics between Unforced and Excited Elevated Transverse Jets

Published online by Cambridge University Press:  14 November 2013

C. M. Hsu  and
R. F. Huang
C. M. Hsu
Affiliation:
Graduate Institute of Applied Science and Technology, National Taiwan University of Scienceand Technology, Taipei, Taiwan 10607, R.O.C.
R. F. Huang*
Affiliation:
Department of Mechanical Engineering, National Taiwan University of Scienceand Technology, Taipei, Taiwan 10607, R.O.C.
*
rfhuang@mail.ntust.edu.tw
Get access

Abstract

The influences of acoustic excitation on the velocity field and mixing characteristic of a jet in cross-flow were investigated in a wind tunnel. The acoustic excitation waves at resonance Strouhal number were generated by a loudspeaker. The time-averaged velocity field and streamlines of the excited elevated transverse jet in the symmetry plane were measured by a high-speed particle image velocimetry. The visual penetration height and spread width were obtained by using an image processing technique. The dispersion characteristics were obtained from the tracer-gas concentration measurement. The results showed that the streamline pattern of the non-excited transverse jet was significantly modified by the acoustic excitation—the bent streamlines evolved from the jet exit escalated and the vortex rings in the jet and tube wakes and the recirculation bubble in the jet wake disappeared. The time-averaged velocity distributions revealed that the excited transverse jet produces large momentum in the up-shooting direction so that the velocity trajectories were located at levels higher than those of the non-excited one. The mixing characteristics, which include the visual penetration height, spread width, and dispersion, were drastically improved by the acoustic excitation due to the changes in the flow structures. The excited transverse jet characterized at larger jet-to-crossflow momentum flux ratios presented larger improvement in the mixing characteristics than at lower jet-to-crossflow momentum flux ratios.

Keywords

Jet in crossflowAcoustic excitationPIVMixing
Type
Research Article
Information
Journal of Mechanics , Volume 30 , Issue 1 , February 2014 , pp. 87 - 96
Copyright
Copyright © The Society of Theoretical and Applied Mechanics, R.O.C. 2014 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1.Kamotani, Y. and Greber, I., “Experiments on a Turbulent Jet in a Crossflow,” AIAA Journal, 10, pp. 1425–1429 (1972).CrossRefGoogle Scholar
2.Pratte, B. D. and Baines, W. D., “Profiles of the Round Turbulent Jet in a Crossflow,” Journal of Hydraulics Division, ASCE, 93, pp. 53–64 (1967).CrossRefGoogle Scholar
3.Smith, S. H. and Mungal, M. G., “Mixing, Structure and Scaling of the Jet in Crossflow,” Journal of Fluid Mechanics, 357, pp. 83–122 (1998).Google Scholar
4.Eiff, O. S. and Keffer, J. F., “On the Structures in the Near-wake Region of an Elevated Turbulent Jet in a Crossflow,” Journal of Fluid Mechanics, 333, pp. 161–195 (1997).CrossRefGoogle Scholar
5.Huang, R. F. and Hsieh, R. H., “An Experimental Study of Elevated Round Jets Deflected in Crosswind,” Experimental Thermal and Fluid Science, 21, pp. 77–86 (2002).Google Scholar
6.Huang, R. F. and Lan, J., “Characteristic Modes and Evolution Processes of Shear-layer Vortices in an Elevated Transverse Jet,” Physics of Fluids, 11, pp. 1–13 (2005).Google Scholar
7.Vermeulen, P. J., Chin, C.-F. and Yu, W. K., “Mixing of an Acoustically Pulsed Air Jet with a Confined Crossflow,” Journal of Propulsion and Power, 6, pp. 777–783 (1990).Google Scholar
8.Gogineni, S., Goss, L. and Roquemore, M., “Manipulation of a Jet in Crossflow,” Experimental Thermal and Fluid Science, 16, pp. 209–219 (1998).Google Scholar
9.Johari, H., Pacheco-Tougas, M. and Hermanson, J. C., “Penetration and Mixing of Fully Modulated Turbulent Jets in Crossflow,” AIAA Journal, 31, pp. 842–850 (1999).Google Scholar
10.Eroglu, A. and Breidenthal, R. E., “Structure, Penetration, and Mixing of Pulsed Jets in Crossflow,” AIAA Journal, 39, pp. 417–423 (2001).CrossRefGoogle Scholar
11.Johari, H., “Scaling of Fully Pulsed Jets in Crossflow,” AIAA Journal, 44, pp. 2719–2725 (2006).CrossRefGoogle Scholar
12.M'Clockey, R. T., King, J. M., Cortelezzi, L. and Karagozian, A. R., “The Actively Controlled Jet in Crossflow,” Journal of Fluid Mechanics, 452, pp. 325–335 (2002).Google Scholar
13.Shapiro, S. R., King, J. M., M'Closkey, R. T. and Karagozian, A. R., “Optimization of Controlled Jets in Crossflow,” AIAA Journal, 44, pp. 1292–1298 (2006).Google Scholar
14.Davitian, J., Hendrickson, C., Getsinger, D.M'Closkey, R. T. and Karagozian, A. R., “Strategic Control of Transverse Jet Shear Layer Instabilities,” AIAA Journal, 48, pp. 2145–2156 (2010).Google Scholar
15.Ginevsky, A. S., Vlasov, Y. V. and Karavosov, R. K., Acoustic Control of Turbulent Jets, Springer-Verlag, Berlin (2004).Google Scholar
16.Keane, R. D. and Adrian, R. J., “Theory of Cross-correlation Analysis of PIV Images,” Applied Scientific Research, 49, pp. 191–215 (1992).Google Scholar
17.Keane, R. D. and Adrian, R. J., “Optimization of Particle Image Velocimeters Part I: Double Pulsed Systems,” Measurement Science and Technology, 1, pp. 1202–1215 (1990).CrossRefGoogle Scholar
18.Shapiro, L. G. and Stockman, G. C., Computer Vision, Prentice Hall, Upper Saddle River, New Jersey (2001).Google Scholar
19.Steele, W. G., Taylor, R. P., Burrell, R. E. and Coleman, H. W., “Use of Previous Experience to Estimate Precision Uncertainty of Small Sample Experiments,” AIAA Journal, 31, pp. 1891–1896 (1993).Google Scholar
20.Anchini, R., Liguori, C. and Paolillo, A., “Evolu-ation of Uncertainty of Edge-detector Algorithms,” IEEE Transaction on Instrumentation and Measurement, 56, pp. 681–688 (2007).CrossRefGoogle Scholar