Skip to main content Accessibility help
×
Home

Transverse-jet shear-layer instabilities. Part 1. Experimental studies

  • S. MEGERIAN (a1), J. DAVITIAN (a1), L. S. DE B. ALVES (a1) and A. R. KARAGOZIAN (a1)

Abstract

This study provides a detailed exploration of the near-field shear-layer instabilities associated with a gaseous jet injected normally into crossflow, also known as the transverse jet. Jet injection from nozzles which are flush as well as elevated with respect to the tunnel wall are explored experimentally in this study, for jet-to-crossflow velocity ratios R in the range 1 ≲ R ≤ 10 and with jet Reynolds numbers of 2000 and 3000. The results indicate that the nature of the transverse jet instability is significantly different from that of the free jet, and that the instability changes in character as the crossflow velocity is increased. Dominant instability modes are observed to be strengthened, to move closer to the jet orifice, and to increase in frequency as crossflow velocity increases for the regime 3.5 < R ≤ 10. The instabilities also exhibit mode shifting downstream along the jet shear layer for either nozzle configuration at these moderately high values of R. When R is reduced below 3.5 in the flush injection experiments, single-mode instabilities are dramatically strengthened, forming almost immediately within the shear layer in addition to harmonic and subharmonic modes, without any evidence of mode shifting. Under these conditions, the dominant and initial mode frequencies tend to decrease with increasing crossflow. In contrast, the instabilities in the elevated jet experiments are weakened as R is reduced below about 4, probably owing to an increase in the vertical coflow magnitude exterior to the elevated nozzle, until R falls below 1.25, at which point the elevated jet instabilities become remarkably similar to those for the flush injected jet. Low-level jet forcing has no appreciable influence on the shear-layer response when these strong modes are present, in contrast to the significant influence of low-level forcing otherwise. These studies suggest profound differences in transverse-jet shear-layer instabilities, depending on the flow regime, and help to explain differences previously observed in transverse jets controlled by strong forcing.

Copyright

Corresponding author

Author to whom correspondence should be addressed: ark@seas.ucla.edu.

References

Hide All
Alves, L., Kelly, R. E. & Karagozian, A. R. 2007 a Local stability analysis of an inviscid transverse jet. J. Fluid Mech. 581, 401418.
Alves, L., Kelly, R. E. & Karagozian, A. R. 2007 b Transverse jet shear layer instabilities. Part 2. Linear analysis for large jet-to-crossflow velocity ratio. J. Fluid Mech. (submitted).
Andreopoulos, J. 1985 On the structure of jets in a crossflow. J. Fluid Mech. 157, 163197.
Blanchard, J. N., Brunet, Y. & Merlen, A. 1999 Influence of a counter rotating vortex pair on the stability of a jet in crossflow: an experimental study by flow visualizations. Exps. Fluids 26, 6374.
Broadwell, J. E. & Breidenthal, R. E. 1984 Structure and mixing of a transverse jet in incompressible flow. J. Fluid Mech. 148, 405412.
Camussi, R., Guj, G. & Stella, A. 2002 Experimental study of a jet in a crossflow at very low Reynolds number. J. Fluid Mech. 454, 113144.
Cortelezzi, L. & Karagozian, A. R. 2001 On the formation of the counter-rotating vortex pair in transverse jets. J. Fluid Mech. 446, 347373.
Eroglu, A. & Breidenthal, R. E. 2001 Structure, penetration, and mixing of pulsed jets in crossflow. AIAA J. 39 (3), 417423.
Fric, T. F. & Roshko, A. 1994 Vortical structure in the wake of a transverse jet. J. Fluid Mech. 279, 147.
Gharib, M., Rambod, E. & Shariff, K. 1998 A universal time scale for vortex ring formation. J. Fluid Mech. 360, 121141.
Ho, C. M. & Huerre, P. 1984 Perturbed free shear layers. Annu. Rev. Fluid Mech. 16, 365424.
Holdeman, J. D. 1993 Mixing of multiple jets in a confined subsonic crossflow. Prog. Energy Combust. Sci. 19, 3170.
Huerre, P. & Monkewitz, P. A. 1990 Local and global instabilities in spatially developing flows. Annu. Rev. Fluid Mech. 22, 473537.
Johari, H., Pacheco-Tougas, M. & Hermanson, J. C. 1999 Penetration and mixing of fully modulated turbulent jets in crossflow. AIAA J. 37, 842850.
Kamotani, Y. & Greber, I. 1972 Experiments on a turbulent jet in a cross flow. AIAA J. 10, 14251429.
Karagozian, A. R. 1986 An analytical model for the vorticity associated with a transverse jet. AIAA J. 24, 429436.
Kelso, R. & Smits, A. 1995 Horseshoe vortex systems resulting from the interaction between a laminar boundary layer and a transverse jet. Phys. Fluids 7, 153158.
Kelso, R. M., Lim, T. T. & Perry, A. E. 1996 An experimental study of round jets in cross-flow. J. Fluid Mech. 306, 111144.
Kibens, V. 1981 The limit of initial shear layer influence on jet development. AIAA Paper 81-1960.
King, J. M. 2002 The actively controlled jet in crossflow. Master's thesis, University of California, Los Angeles, Department of Mechanical and Aerospace Engineering.
M'Closkey, R. T., King, J., Cortelezzi, L. & Karagozian, A. R. 2002 The actively controlled jet in crossflow. J. Fluid Mech. 452, 325335.
Margason, R. J. 1993 Fifty years of jet in cross flow research. AGARD CP 534 1, 1141.
Megerian, S. & Karagozian, A. R. 2005 Evolution of shear layer instabilities in the transverse jet. In 43rd AIAA Aerospace Sci. Conf. Paper 2005-0142.
Michalke, A. 1971 Instabilität eines kompressiblen runden freistrahls unter berücksichtigung des einflusses der strahlgrenzschichtdicke. Z. Flugwiss. 19 (8–9), 319328. In English: NASA TM 75190 (1977).
Michalke, A. & Hermann, G. 1982 On the inviscid instability of a circular jet with external flow. J. Fluid Mech. 114, 343359.
Monkewitz, P. A., Bechert, D. W., Barsikow, B. & Lehmann, B. 1990 Self-excited oscillations and mixing in a heated round jet. J. Fluid Mech. 213, 611639.
Moussa, Z. M., Trischka, J. W. & Eskinazi, S. 1977 The nearfield in the mixing of a round jet with a cross-stream. J. Fluid Mech. 80, 4980.
Narayanan, S., Barooah, P. & Cohen, J. M. 2003 Dynamics and control of an isolated jet in crossflow. AIAA J. 41, 23162330.
Petersen, R. A. & Samet, M. M. 1988 On the preferred mode of jet instability. J. Fluid Mech. 194, 153173.
Peterson, S. D. & Plesniak, M. W. 2004 Evolution of jets emanating from short holes into crossflow. J. Fluid Mech. 503, 5791.
Raman, G., Rice, E. J. & Reshotko, E. 1994 Mode spectra of natural disturbances in a circular jet and the effect of acoustic forcing. Exps Fluids 17, 415426.
Rudman, M. 1996 Simulation of the near field of a jet in cross flow. Expl Thermal Fluid Sci. 12, 134141.
Schuller, T., King, J., Majamaki, A. & Karagozian, A. R. 1999 An experimental study of acoustically controlled gas jets in crossflow. Bull. Am. Phys. Soc. 44, 111.
Shapiro, S. R. 2003 Optimization of controlled jets in crossflow. Master's thesis, University of California, Los Angeles, Department of Mechanical and Aerospace Engineering.
Shapiro, S., King, J., M'Closkey, R. T. & Karagozian, A. R. 2006 Optimization of controlled jets in crossflow. AIAA J. 44, 12921298.
Smith, S. H. & Mungal, M. G. 1998 Mixing, structure and scaling of the jet in crossflow. J. Fluid Mech. 357, 83122.
Strykowski, P. J. & Niccum, D. L. 1991 The stability of countercurrent mixing layers in circular jets. J. Fluid Mech. 227, 309343.
Vermeulen, P. J., Grabinski, P. & Ramesh, V. 1992 Mixing of an acoustically excited air jet J: with a confined hot crossflow. Trans. ASME J: Engng. Gas Turbines Power 114, 4654.
Xu, G. & Antonia, R. A. 2002 Effect of different initial conditions on a turbulent round free jet. Exps Fluids 33, 677683.
Yuan, L. L. & Street, R. L. 1998 Trajectory and entrainment of a round jet in crossflow. Phys. Fluids 10, 23232335.
MathJax
MathJax is a JavaScript display engine for mathematics. For more information see http://www.mathjax.org.

Transverse-jet shear-layer instabilities. Part 1. Experimental studies

  • S. MEGERIAN (a1), J. DAVITIAN (a1), L. S. DE B. ALVES (a1) and A. R. KARAGOZIAN (a1)

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed