Skip to main content
    • Aa
    • Aa

Thermal effects on the wake of a heated circular cylinder operating in mixed convection regime

  • H. Hu (a1) and M. M. Koochesfahani (a2)

The thermal effects on the wake flow behind a heated circular cylinder operating in the mixed convection regime were investigated experimentally in the present study. The experiments were conducted in a vertical water channel with the heated cylinder placed horizontally and the flow approaching the cylinder downwards. With such a flow arrangement, the direction of the thermally induced buoyancy force acting on the fluid surrounding the heated cylinder would be opposite to the approach flow. During the experiments, the temperature and Reynolds number of the approach flow were held constant. By adjusting the surface temperature of the heated cylinder, the corresponding Richardson number () was varied between 0.0 (unheated) and 1.04, resulting in a change in the heat transfer process from forced convection to mixed convection. A novel flow diagnostic technique, molecular tagging velocimetry and thermometry (MTV&T), was used for qualitative flow visualization of thermally induced flow structures and quantitative, simultaneous measurements of flow velocity and temperature distributions in the wake of the heated cylinder. With increasing temperature of the heated cylinder (i.e. Richardson number), significant modifications of the wake flow pattern and wake vortex shedding process were clearly revealed. When the Richardson number was relatively small (), the vortex shedding process in the wake of the heated cylinder was found to be quite similar to that of an unheated cylinder. As the Richardson number increased to , the wake vortex shedding process was found to be ‘delayed’, with the wake vortex structures beginning to shed much further downstream. As the Richardson number approached unity (), instead of having ‘Kármán’ vortices shedding alternately at the two sides of the heated cylinder, concurrent shedding of smaller vortex structures was observed in the near wake of the heated cylinder. The smaller vortex structures were found to behave more like ‘Kelvin–Helmholtz’ vortices than ‘Kármán’ vortices, and adjacent small vortices would merge to form larger vortex structures further downstream. It was also found that the shedding frequency of the wake vortex structures decreased with increasing Richardson number. The wake closure length and the drag coefficient of the heated cylinder were found initially to decrease slightly when the Richardson number was relatively small (), and then to increase monotonically with increasing Richardson number as the Richardson number became relatively large (). The average Nusselt number () of the heated cylinder was found to decrease almost linearly with increasing Richardson number.

Corresponding author
Email address for correspondence:
Linked references
Hide All

This list contains references from the content that can be linked to their source. For a full set of references and notes please see the PDF or HTML where available.

1. H. M. Badr 1983 A theoretical study of laminar mixed convection from a horizontal cylinder in a cross stream. Intl J. Heat Mass Transfer 26, 639653.

2. H. M. Badr 1984 Laminar combined convection a horizontal cylinder – parallel and contra flow regimes. Intl J. Heat Mass Transfer 27, 1527.

3. E. Berger & R. Wille 1972 Periodic flow phenomena. Annu. Rev. Fluid Mech. 4, 313.

4. D. Bohl & M. M. Koochesfahani 2009 MTV measurements of the vortical field in the wake of an aerofoil oscillating at high reduced frequency. J. Fluid Mech. 620, 6388.

5. K. S. Chang & J. Y. Sa 1990 The effect of buoyancy on vortex shedding in the near wake of a circular cylinder. J. Fluid Mech. 220, 253266.

8. C. P. Gendrich & M. M. Koochesfahani 1996 A spatial correlation technique for estimating velocity fields using molecular tagging velocimetry (MTV). Exp. Fluids 22 (1), 6777.

9. C. P. Gendrich , M. M. Koochesfahani & D. G. Nocera 1997 Molecular tagging velocimetry and other novel application of a new phosphorescent supramolecule. Exp. Fluids 23, 361372.

10. W. K. Hartmann , M. H. B. Gray , A. Ponce & D. G. Nocera 1996 Substrate induced phosphorescence from cyclodextrin–lumophore host–guest complex. Inorg. Chim. Acta 243, 239248.

11. A. P. Hatton , D. D. James & H. W. Swire 1970 Combined forced and nature convection with low speed air flow over horizontal cylinders. J. Fluid Mech. 42, 1731.

12. H. Hu , Z. Jin , D. Nocera , C. Lum & M. Koochesfahani 2010 Experimental investigations of micro-scale flow and heat transfer phenomena by using molecular tagging techniques. Meas. Sci. Technol. 21 (8) 085401(15pp).

13. H. Hu & M. M. Koochesfahani 2003 A novel technique for quantitative temperature mapping in liquid by measuring the lifetime of laser induced phosphorescence. J. Vis. 6 (2), 143153.

15. H. Hu & M. M. Koochesfahani 2006 Molecular tagging velocimetry and thermometry (MTV&T) technique and its application to the wake of a heated circular cylinder. Meas. Sci. Technol. 17 (6), 12691281.

16. H. Hu , C. Lum & M. M. Koochesfahani 2006 Molecular tagging thermometry with adjustable temperature sensitivity. Exp. Fluids 40 (5), 753763.

18. R. N. Kieft , C. C. M. Rindt & A. A. van Steenhoven 1999 The wake behaviour behind a heated horizontal cylinder. Exp. Therm. Fluid Sci. 19, 193193.

23. W. J. P. M. Maas , C. C. Rindt & A. A. van Steenhoven 2003 The influence of heat on the 3D-transition of von Kármán vortex street. Intl J. Heat Mass Transfer 46, 30693081.

24. N. Michaux-Leblond & M. Belorgey 1997 Near wake behaviour of a heated circular cylinder: viscosity–buoyancy duality. Exp. Therm. Fluid Sci. 15, 91100.

25. V. T. Morgan 1975 The overall heat transfer from smooth circular cylinders. Adv. Heat Transfer 11, 199264.

27. H. Oertel Jr 1990 Wakes behind blunt bodies. Annu. Rev. Fluid Mech. 22, 539564.

28. P. H. Oosthuizen & S. Madan 1970 Combined convective heat transfer from horizontal cylinders in air. J. Heat Transfer 92, 11941196.

29. P. H. Oosthuizen & S. Madan 1971 The effect of flow direction on combined convective heat transfer from cylinders to air. J. Heat Transfer 93, 240242.

30. H. G. Park , D. Dabiri & M. Gharib 2001 Digital particle image velocimetry/thermometry and application to the wake of a heated circular cylinder. Exp. Fluids 30, 327338.

31. A. Ponce , P. A. Wong , J. J. Way & D. G. Nocera 1993 Intense phosphorescence trigged by alcohol upon formation of a cyclodextrin ternary complex. J. Phys. Chem. 97, 1113711142.

35. M. B. Shafii , C. L. Lum & M. M. Koochesfahani 2010 In-situ LIF temperature measurements in aqueous ammonium chloride solution during uni-directional solidification. Exp. Fluids 48, 651662.

36. A. A. van Steenhoven & C. C. M. Rindt 2003 Flow transition behind a heated cylinder. Intl J. Heat Fluid Flow 24, 322333.

37. S. L. Thomson & D. Maynes 2001 Spatially resolved temperature measurement in a liquid using laser induced phosphorescence. J. Fluid Engng 123, 293302.

38. T. Vít , M. Ren , Z. Travnicek , F. Marsik & C. C. M. Rindt 2007 The influence of temperature gradient on the Strouhal–Reynolds number relationship for water and air. Exp. Therm. Fluid Sci. 31, 751760.

39. A. Wang , Z. Travnicek & K. Chia 2000 On the relationship of effective Reynolds number and Strouhal number for the laminar vortex shedding of a heated circular cylinder. Phys. Fluids 12 (6), 14011410.

40. C. H. K. Williamson 1988 Defining a universal and continuous Strouhal–Reynolds number relationship for the laminar vortex shedding of a circular cylinder. Phys. Fluids 31 (10), 27422744.

41. C. H. K. Williamson 1996 Vortex dynamics in the cylinder wake. Annu. Rev. Fluid Mech. 28, 477526.

Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Journal of Fluid Mechanics
  • ISSN: 0022-1120
  • EISSN: 1469-7645
  • URL: /core/journals/journal-of-fluid-mechanics
Please enter your name
Please enter a valid email address
Who would you like to send this to? *



Full text views

Total number of HTML views: 0
Total number of PDF views: 37 *
Loading metrics...

Abstract views

Total abstract views: 309 *
Loading metrics...

* Views captured on Cambridge Core between September 2016 - 23rd September 2017. This data will be updated every 24 hours.