THERMAL SCIENCE

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Ponnambalam Manivannan

,

B. T. N. Sridhar

CHARACTERISTIC STUDY OF NON-CIRCULAR INCOMPRESSIBLE FREE JET

ABSTRACT
This paper reports an experimental investigation of bulk properties of turbulent, which is three dimensional, incompressible, air jets issuing into still air surrounding from the nozzles. The jet orifices utilized included circular, hexagonal and cruciform geometries. Experimental results of pertinent mean flow properties such as axis velocity decay, half width growth, potential core and turbulence intensities are reported. Single Hotwire anemometer was used for measurements of the velocity field. The experiment for the three jets was conducted under the same nominal conditions with the exit Reynolds number of 15,400. Consistent with previous investigations of other non circular jets, the cruciform jet is found to have an overall superior mixing capability over the circular counter part. Immediately downstream of the nozzle exit, it entrains, and then mixes with, the surroundings at a higher rate. This jet has a shorter potential core with higher rates of decay and spread than the circular jet. This phenomenon of axis switching is also found to occur in this jet.
KEYWORDS
noncircular jets, cruciform, hexagon, half width, turbulence intensity
PAPER SUBMITTED: 2011-02-08
PAPER REVISED: 2011-09-07
PAPER ACCEPTED: 2011-10-08
DOI REFERENCE: https://doi.org/10.2298/TSCI110208116M
CITATION EXPORT: view in browser or download as text file
THERMAL SCIENCE YEAR 2013, VOLUME 17, ISSUE Issue 3, PAGES [787 - 800]
REFERENCES
  1. . Boersma, B.J., Brethouwer, G., Nieuwstadt, F.T.M., A Numerical Investigation on the Effect of the Inflow Conditions on the Self-similar Region of a Round Jet, Physics of Fluids,10 , pp. 899- 909.
  2. . Capp, S.P., Hussein, H.J., George, W.K., Velocity Measurements in a High Reynolds Number Momentum-conserving, Axisymmetric, Turbulent Jets, Technical Report. 123. Turbulence Research Laboratory, University at Buffalo, Suny .
  3. . Christopher, O. Iyogun., and Madjid Birouk., Effect of Sudden Expansion on Entrainment and Spreading Rates of a Jet Issuing from Asymmetric Nozzles, Journal of Flow Turbulence Combustion, 82 , 3, pp. 287-315.
  4. . Ferdman, E., Otugen, M.V., Kim, S., Effect of Initial Velocity Profile on the Development of Round jets, Journal of Propulsion Power, 16 , pp. 676-686.
  5. . Grinstein, F.F., Self-induced Vortex Ring Dynamics in Subsonic Rectangular Jets, Physics of Fluids, 7 , pp. 2519-2521.
  6. . Grinstein, F.F., Gutmark, E., Parr, T., Near Field Dynamics of Subsonic Free Square Jets, A Computational and Experimental Study, Physics of Fluids, 7 , pp. 1483-1497.
  7. . Gutmark, E., Grinstein, F.F., Flow Control with Noncircular Jets, Annual Review of Fluid Mechanics, 31 , pp. 239-272.
  8. . Gutmark, E., Schadow, K.C., Parr, T.P., Hanson-Parr, D.M., Wilson, K.J., Noncircular Jets in Combustion Systems, Experiments in Fluids, 7 , pp. 248-258.
  9. . Gutmark, E., Schadow, K.C., Wilson, K.J., Subsonic and Supersonic Combustion Using Noncircular Injectors, Journal of Propulsion Power, 27 , pp. 240-249.
  10. . Ho, C., Gutmark, E., Vortex Induction and Mass Entrainment in a Small-aspect-ratio Elliptic Jet, Journal of Fluid Mechanics, 179 , pp. 383-405.
  11. . Hussein, H.J., Capp, S.P., George, W.K., Velocity Measurements in a High-Reynolds-number, Momentum-Conserving, Axisymmetric, Turbulent Jet, Journal of Fluid Mechanics, 258 , pp. 31-75.
  12. . Koshigoe, S., Gutmark, E., Shadow, K., Initial Development of Non-circular Jet Leading to Axis Switching, AAIA Journal, 27 , pp. 439.
  13. . Mi,J., Nathan,G.J., Luxton,R.E., Centerline Mixing Characteristics of Jets from Nine Differently Shaped Nozzles, Experiments in Fluids, 28 , pp. 93-94.
  14. . Mi, J., Nathan, G.J., Nobes, D.S., Mixing Characteristics of Axisymmetric Free Jets from a Contoured Nozzle, an Orifice Plate and a Pipe, Journal of Fluids Engineering, 123 , pp. 878- 883.
  15. . Miler, R.S., Madnia, C.K., Givi.P., Numerical Simulations of Non-circular Jets, Journal of Computers & Fluids, 24 , pp. 1-25.
  16. . Panchapakesan, N.R., Lumley, J.L., Turbulence Measurements in Axisymmetric Jets of Air and Helium. 1. Air jet, Journal of Fluid Mechanics, 246 , pp. 197-223.
  17. . Quinn, W.R., On Mixing in an Elliptic Turbulent Free Jet, Physics of Fluids A 1 , pp. 1716-1722.
  18. . Quinn, W.R., Measurements in the Near Flow Field of an Isosceles Triangular Free Jet, Experiments of Fluids, 39 , pp. 111-126.
  19. . Rodi, W., A New Method of Analyzing Hot-wire Signals in Highly Turbulent Flow and its Evaluation in a Round Jet, DISA Inf. 17, [1975, Feb]
  20. . Sau, A., Vortex Dynamics and Mass Entrainment in a Rectangular Channel with a Suddenly Expanded and Contracted Part, Physics of Fluids, 14 , pp. 3280-3308.
  21. . Sau, A., Generation of Streamwise Vortices in Square Sudden-expansion Flows, Physics Review. E 69 , pp. 1-10. . Shigetaka Fujita., Hideo Osaka., Effect of Aspect Ratios on Potential Core Length for Cruciform Jet, Experimental Thermal and Fluid Science, 5 , pp. 332-337.
  22. . Vagt, J.D., Hotwire Probes in Low Speed Flow, Prog. Aerospace Science, 18 , pp. 271- 323.
  23. . Warda, H.A., Kassab, S.Z., Elshorbagy, K.A., Elsaadawy, E.A., An Experimental Investigation of the Near-field Region of Free Turbulent Round Central and Annular Jet, Journal of Flow Measurement and Instrumentation, 10 , pp. 1-14.
  24. . Wygnanski, I., Fiedler, H., Some Measurements in the Self-preserving Jets, Journal of Fluid Mechanics, 38 , pp. 577-612.
  25. . Xu, G., Antonia, R.A., Effect of Different Initial Conditions on a Turbulent Round Free Jet, Experiments of Fluids, 33 , pp. 677-683.
  26. . Zaman, K.B.M.Q., Spreading Characteristics of Compressible Jets from Nozzles of Various Geometries, Journal of Fluid mechanics, 383 , pp. 197-228.
  27. . Zaman, K.B.M.Q., Axis Switching and Spreading of an Asymmetric Jet: the Role of Coherent Structure Dynamics, Journal of Fluid Mechanics, 316 , pp. 1-27.
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Characteristic study of non-circular incompressible free jet

© 2024 Society of Thermal Engineers of Serbia. Published by the Vinča Institute of Nuclear Sciences, National Institute of the Republic of Serbia, Belgrade, Serbia. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International licence