THERMAL SCIENCE

International Scientific Journal

INFLUENCE OF UPSTREAM FLOW CHARACTERISTICS ON THE REATTACHMENT PHENOMENON IN SHALLOW CAVITIES

ABSTRACT
The influence of the upstream flow characteristics on the behavior of the flow over a shallow cavity and on the reattachment phenomenon is examined in this paper. Accordingly, a comparison of the cavity’s flow structure is performed for two different upstream flows: the wall jet flow and the boundary layer flow. The wall jet possesses a particular structure with two regions: an inner layer analogous to that of a boundary layer and an outer layer similar to that of a free jet; this layer is an additional source of turbulence production in addition to that of the inner shear layer. The present study interested to the effect of this external layer on the shallow cavity’s flow. The numerical approach is based on the low Reynolds stress-omega turbulence model. Fluent 6.3 and the pre-processor Gambit 2.3 are used for the computation. The numerical results indicate that the flow structure is very sensitive to the upstream flow’s characteristics. Indeed, for the same Reynolds number and the same boundary layer thickness at the cavity leading edge, the cavity flow structure in a wall jet upstream flow case differs considerably from that of a boundary layer upstream flow. The most important finding is the earlier reattachment process in the wall jet inflow case, where an important reduction of the reattachment length is observed compared to that of a cavity under a boundary layer flow.
KEYWORDS
PAPER SUBMITTED: 2010-12-03
PAPER REVISED: 2010-01-27
PAPER ACCEPTED: 2011-02-15
DOI REFERENCE: https://doi.org/10.2298/TSCI101203019M
CITATION EXPORT: view in browser or download as text file
THERMAL SCIENCE YEAR 2011, VOLUME 15, ISSUE Issue 3, PAGES [721 - 734]
REFERENCES
  1. Mehrez, Z., Bouterra, M., El Cafsi, A., Belghith, A., Le Quere, P., Mass transfer control of a backward facing step flow by local forcing effect of Reynolds number, Thermal Science Journal,(2010), doi: 10.2298/Tsc 09102704M.
  2. Mushatet Khudheyer, S., Simulation of turbulent flow and heat transfer over a backward facing step with ribs turbulators, Thermal Science Journal,(2010), doi:10.2298/TSCI 090926044M.
  3. Logan, E., Prapoj, P., Chang, J., A comparison of wake characteristics of model and prototype buildings in transverse winds, NASA contractor report N° 3008, 1978.
  4. Oka, S., Kostic, Z., Flow field past a single roughness element in channel of rectangular cross section, in Heat and mass transfer in a boundary layer, (Afgan, N.H., Zaric, Z. and Anastasiyevic, P.), Pergamon Press, Vol. 1, pp. 425-435, 1972.
  5. Oka, S., Flow Field Between two Roughness Elements in Developed Turbulent Chanel Flow, in Heat and Mass Transfer in Flows with Separated Regions and Measurement Techniques, Pergamon press, 1972
  6. Mudgal, B.V. and Pani, B.S., Flow around obstacles in plane turbulent wall jets, Journal of Wind Engineering and Industrial Aerodynamics, 73 (1998), pp. 193-213.
  7. Kanna, R. P. and Das, M. K., Numerical simulation of two-dimensional laminar Incompressible offset jet flows, International journal for numerical methods in fluids, 49 (2005), pp. 439-464.
  8. Bajura, R. A. and Szewczyk, A. A., Experimental Investigation of a Laminar Two- Dimensional Plane Wall Jet, Phys. Fluids, 13 (1970), pp. 1653-1664.
  9. Eriksson, J., Karlsson, R. I., Persson, J. An experimental study of a two -dimensional plane turbulent wall jet, Experiments in Fluids, 25 (1998), pp. 50-60.
  10. Badri, K., Étude expérimentale d'un écoulement turbulent en aval d'une marche descendante: cas d'un jet pariétal et de la couche limite, doctoral thesis, École doctorale Sciences pour l'ingénieur de Nantes, 1993.
  11. Jacob, M. C., Louisot, A., Juve, D. and Guerrand, S., Experimental study of sound generated by backward facing steps under wall jet. AIAA Journal, 392(2001), 7, pp. 1254-1260.
  12. Nait Bouda, N., Schiestel, R., Amielh, M., Rey, C. and Benabid, T., Experimental approach and numerical prediction of turbulent wall jet over a backward facing step, International Journal of Heat and Fluids Flow, 29 (2008), 4, pp. 927-944.
  13. Ganesh, R., Edmane, E., Timoty, J. B, Tone noise and nearfield pressure produced by jet-cavity interaction, Nasa Technical Report No. TM- 20883, 1998.
  14. Gloerfelt, X., Bailly, C. and Juvé, D., Direct computational of the noise radiation by a subsonic cavity flow and application of integral methods, Journal of sound and vibration, 266 (2003), pp. 119-146.
  15. Ahuja, K. K., Mendoza, J., Effects of cavity dimensions, boundary layer and temperature on cavity noise with emphasis on benchmark data to validate computational aeroacoustic codes, NASA Contractor Report No. 4653, 1995.
  16. Colonius, T., Basu, A. J., Rowley, C. W., Numerical investigation of flow past a cavity, AIAA paper, 99 (1912), 5th AIAA/CEAS Aeroacoustics conference, Greater Seattle, Washington, 1999.
  17. Zdanski, P. S. B, Ortega, M. A., Nide, G. C. R., Fico, Tr., On the flow over cavities of large
  18. aspect ratio: a physical analysis, International Communications in Heat and Mass Transfer, 33 (2006), 4, pp. 458-466.
  19. Alammar, K. N., Effect of cavity aspect ratio on flow and heat transfer characteristics in pipes: a numerical study, Heat and mass transfer, 42 (2006), 9, pp. 861-866.
  20. Wilcox, D. C., Turbulence Modelling for CFD, DCW Industries, Inc., La Canada, California, Second edition,1998.
  21. Patankar, S.V., Numerical heat transfer and fluid flow, Series in computational methods in mechanics and thermal sciences, hemisphere Publishing Corporation, 1980.
  22. Abrahamsson, H., Johansson, B. and Löfdahl, L., A turbulent plane two-dimensional wall-jet in a quiescent surrounding, European journal of mechanics. B, Fluids, (1994), 13, pp. 533-556.
  23. Karlsson, R., Eriksson, J. and Persson, J., An experimental study of a two-dimensional plane turbulent wall jet, Technical report No.VU-S93-B3, Vattenfall Utveckling AB, Älvkarleby Laboratory, Sweden , 1993.
  24. Wygnanski, I., Katz, Y. and Horev, E., On the applicability of various scaling laws to the turbulent wall jet, Journal of. Fluid Mechanics, 234 (1992), pp. 669- 690.
  25. Roshko, A., Some measurements of flow in a rectangular cutout. NACA Technical Note, No. 3448, 1955.
  26. Plentovich, E. B, Stallings, Jr. R. L. and Tracy, M. B., Experimental cavity pressure measurements at subsonic speeds, Nasa Technical Paper, No. 3358, 1993.
  27. Avelar, A. C., Fico, N. G C R, and Mello, O. A. F., Three-dimensional flow over shallow cavities, 37 th AIAA Fluid Dynamics Conference and Exhibit, 4234, 2007.
  28. Zdanski, P. S. B, Ortega, M. A., Nide, G. C. R. And Fico, Tr., Numerical study of the flow over shallow cavities, Computers & Fluids, 32 (2003), 7, pp. 953-974.

© 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