Supersonic impinging jets produce a highly unsteady flowfield leading to very high dynamic pressure loads on nearby surfaces. In earlier studies, we conclusively demonstrated that arrays of supersonic microjet, 400 μm in diameter, effectively disrupted the feedback loop inherent in high-speed impinging jet flows. This feedback disruption results in significant reductions in the adverse effects associated with such flows. In this paper, by primarily using detailed velocity field measurements, we examine the role of streamwise vorticity in order to better understand the mechanisms behind this control scheme. The velocity field measurements clearly reveal the presence of well-organized, streamwise vortices with the activation of microjets. This increase in streamwise vorticity is concomitant with a reduction in the azimuthal vorticity of the primary jet. We propose that the streamwise vorticity is mainly a result of the redirection of the azimuthal vorticity, which leads to a weakening of the large-scale structures in the primary jet. The appearance of strong vortices in the shear layer near the nozzle exit due to microjets further weakens the spatial coherence of the coupling between the acoustic waves and shear layer instability, while thickening the jet shear layer. All these effects are thought to be collectively responsible for the efficient disruption of the feedback loop using microjets.
Skip Nav Destination
ASME/JSME 2003 4th Joint Fluids Summer Engineering Conference
July 6–10, 2003
Honolulu, Hawaii, USA
Conference Sponsors:
- Fluids Engineering Division
ISBN:
0-7918-3697-5
PROCEEDINGS PAPER
The Role of Streamwise Vorticity in the Control of Impinging Jets
F. S. Alvi,
F. S. Alvi
Florida A&M University - Florida State University, Tallahassee, FL
Search for other works by this author on:
H. Lou,
H. Lou
Florida A&M University - Florida State University, Tallahassee, FL
Search for other works by this author on:
C. Shih
C. Shih
Florida A&M University - Florida State University, Tallahassee, FL
Search for other works by this author on:
F. S. Alvi
Florida A&M University - Florida State University, Tallahassee, FL
H. Lou
Florida A&M University - Florida State University, Tallahassee, FL
C. Shih
Florida A&M University - Florida State University, Tallahassee, FL
Paper No:
FEDSM2003-45062, pp. 327-333; 7 pages
Published Online:
February 4, 2009
Citation
Alvi, FS, Lou, H, & Shih, C. "The Role of Streamwise Vorticity in the Control of Impinging Jets." Proceedings of the ASME/JSME 2003 4th Joint Fluids Summer Engineering Conference. Volume 2: Symposia, Parts A, B, and C. Honolulu, Hawaii, USA. July 6–10, 2003. pp. 327-333. ASME. https://doi.org/10.1115/FEDSM2003-45062
Download citation file:
5
Views
Related Articles
Effect of Jet Oscillation on the Maximum Impingement Plate Skin Friction
J. Fluids Eng (September,2018)
Buoyancy Dominated He – O 2 Separated Jet Mixing in a Tubular Reactor
J. Fluids Eng (September,2008)
Related Chapters
Cavitating Structures at Inception in Turbulent Shear Flow
Proceedings of the 10th International Symposium on Cavitation (CAV2018)
Pulsating Supercavities: Occurrence and Behavior
Proceedings of the 10th International Symposium on Cavitation (CAV2018)
A Simple Carburetor
Case Studies in Fluid Mechanics with Sensitivities to Governing Variables