- Physical Review Journals
All JournalsPhysics Magazine
Access Provided by Xinjiang University

Physical Review Fluids

Reuse & Permissions

It is not necessary to obtain permission to reuse this article or its components as it is available under the terms of the Creative Commons Attribution 4.0 International license. This license permits unrestricted use, distribution, and reproduction in any medium, provided attribution to the author(s) and the published article's title, journal citation, and DOI are maintained. Please note that some figures may have been included with permission from other third parties. It is your responsibility to obtain the proper permission from the rights holder directly for these figures.

Export citation

Export citation

Choose format for download:

Download Citation
  • Open Access
  • Access by Xinjiang University

Influence of freestream turbulence on the near-field growth of a turbulent cylinder wake: Turbulent entrainment and wake meandering

K. S. Kankanwadi and O. R. H. Buxton

  • Department of Aeronautics, Imperial College London SW7 2AZ, United Kingdom

PDF

Phys. Rev. Fluids 8, 034603 – Published 13 March, 2023

DOI: https://doi.org/10.1103/PhysRevFluids.8.034603

Abstract

The effect of freestream turbulence on the spreading of the near wake of a circular cylinder (<11 cylinder diameters from the rear face of the cylinder) is investigated through particle image velocimetry data. Different “flavors” of freestream turbulence, in which the turbulence intensity and integral length scale are independently varied, are subjected to the cylinder. The time-averaged spreading of the near wake is decoupled into the growth through entrainment of background fluid and the envelope of the spatial extent of the instantaneous wake due to wake “meandering,” induced by the presence of large-scale vortical coherent structures, i.e., the von Kármán vortex street. Unlike for the far-field of a turbulent wake, examined by Kankanwadi and Buxton [J. Fluid Mech. 905, A35 (2020)], it is shown that freestream turbulence enhances the entrainment rate into the wake in comparison to a nonturbulent background. Furthermore, both the turbulence intensity and the integral length scale of the background turbulence are important in this regard, further contrasting to the far wake where only the turbulence intensity is important. Additionally, wake meandering is enhanced by the presence of background turbulence, and here the integral length scale is the dominant parameter. Combining these findings yields the oft-reported result that background turbulence enhances the time-averaged near-wake growth rate. The influence of wake meandering is isolated by conducting similar experiments in which a splitter plate is mounted to the rear face of the cylinder, thereby eliminating the von Kármán vortex street. These results show that when large-scale vortices are not present within the turbulent wake then freestream turbulence actually suppresses the entrainment rate, relative to a nonturbulent background, in results that mirror Kankanwadi and Buxton [J. Fluid Mech. 905, A35 (2020)]. We therefore postulate that freestream turbulence has the effect to enhance large-scale entrainment via engulfment, but suppress entrainment via small-scale nibbling. Finally, we observe that the presence of freestream turbulence occasionally leads to a transient elimination of vortex shedding, an effect that is bound to have consequences on the instantaneous entrainment rate as outlined above.

View figure in article

Physics Subject Headings (PhySH)

Article Text

References (42)

  1. J. Meyers and C. Meneveau, Optimal turbine spacing in fully developed wind farm boundary layers, Wind Energy 15, 305 (2012).
  2. Z.-T. Xie, O. Coceal, and I. P. Castro, Large-eddy simulation of flows over random urban-like obstacles, Bound. Layer Meteorol. 129, 1 (2008).
  3. E. Aristodemou, L. M. Boganegra, L. Mottet, D. Pavlidis, A. Constantinou, C. Pain, A. Robins, and H. ApSimon, How tall buildings affect turbulent air flows and dispersion of pollution within a neighbourhood, Environ. Pollut. (Oxford, UK) 233, 782 (2018).
  4. C. H. K. Williamson, Vortex dynamics in the cylinder wake, Annu. Rev. Fluid Mech. 28, 477 (1996).
  5. P. W. Bearman and T. Morel, Effect of free stream turbulence on the flow around bluff bodies, Prog. Aerosp. Sci. 20, 97 (1983).
  6. I. Eames, C. Jonsson, and P. B. Johnson, The growth of a cylinder wake in turbulent flow, J. Turbul. 12, N39 (2011).
  7. C. B. da Silva, J. C. R. Hunt, I. Eames, and J. Westerweel, Interfacial layers between regions of different turbulence intensity, Annu. Rev. Fluid Mech. 46, 567 (2014).
  8. S. Corrsin and A. L. Kistler, Free-stream boundaries of turbulent flows, NACA technical report No. NACA-TR-1244, National Advisory Committee for Aeronautics, 1955, p. 1955.
  9. M. Holzner, A. Liberzon, N. Nikitin, W. Kinzelbach, and A. Tsinober, Small-scale aspects of flows in proximity of the turbulent/nonturbulent interface, Phys. Fluids 19, 071702 (2007).
  10. A. J. Yule, Large-scale structure in the mixing layer of a round jet, J. Fluid Mech. 89, 413 (1978).
  11. K. S. Kankanwadi and O. R. H. Buxton, Turbulent entrainment into a cylinder wake from a turbulent background, J. Fluid Mech. 905, A35 (2020).
  12. K. S. Kankanwadi and O. R. H. Buxton, On the physical nature of the turbulent/turbulent interface, J. Fluid Mech. 942, A31 (2022).
  13. A. Niayifar and F. Porté-Agel, Analytical modeling of wind farms: A new approach for power prediction, Energies (Basel, Switz) 9, 741 (2016).
  14. M. Bastankhah and F. Porté-Agel, A new analytical model for wind-turbine wakes, Renewable Energy 70, 116 (2014).
  15. W. K. George, The self-preservation of turbulent flows and its relation to initial conditions and coherent structures, Adv. Turbul. 3973 (1989).
  16. J. C. Vassilicos, Dissipation in turbulent flows, Annu. Rev. Fluid Mech. 47, 95 (2015).
  17. L. J. Vermeer, J. N. Sørensen, and A. Crespo, Wind turbine wake aerodynamics, Prog. Aerosp. Sci. 39, 467 (2003).
  18. C. Vanderwel and S. Tavoularis, On the accuracy of PLIF measurements in slender plumes, Exp. Fluids 55, 1801 (2014).
  19. C. Arcoumanis, J. J. McGuirk, and J. M. L. M. Palma, On the use of fluorescent dyes for concentration measurements in water flows, Exp. Fluids 10, 177 (1990).
  20. K. S. Kankanwadi, Ph.D. thesis, Imperial College London, 2022 (unpublished).
  21. P. Baj, P. J. K. Bruce, and O. R. H. Buxton, On a PLIF quantification methodology in a nonlinear dye response regime, Exp. Fluids 57, 106 (2016).
  22. W. J. A. Dahm and P. E. Dimotakis, Measurements of entrainment and mixing in turbulent jets, AIAA J. 25, 1216 (1987).
  23. W. J. A. Dahm and P. E. Dimotakis, Mixing at large schmidt number in the self-similar far field of turbulent jets, J. Fluid Mech. 217, 299 (1990).
  24. H. C. Burridge, D. A. Parker, and E. S. Kruger, Conditional sampling of a high Peclet number turbulent plume and the implications for entrainment, J. Fluid Mech. 823, 26 (2017).
  25. D. Mistry, J. Philip, J. R. Dawson, and I. Marusic, Entrainment at multi-scales across the turbulent/non-turbulent interface in an axisymmetric jet, J. Fluid Mech. 802, 690 (2016).
  26. W. C. Reynolds and A. K. M. F. Hussain, The mechanics of an organized wave in turbulent shear flow. Part 3. Theoretical models and comparisons with experiments, J. Fluid Mech. 54, 263 (1972).
  27. K. M. F. Hussain and W. C. Reynolds, The mechanics of an organized wave in turbulent shear flow, J. Fluid Mech. 41, 241 (1970).
  28. B. J. Cantwell and D. Coles, An experimental study of entrainment and transport in the turbulent near wake of a circular cylinder, J. Fluid Mech. 136, 321 (1983).
  29. P. Baj, P. J. K. Bruce, and O. R. H. Buxton, The triple decomposition of a fluctuating velocity field in a multiscale flow, Phys. Fluids 27, 075104 (2015).
  30. A. Wynn, D. S. Pearson, B. Ganapathisubramani, and P. J. Goulart, Optimal mode decomposition for unsteady flows, J. Fluid Mech. 733, 473 (2013).
  31. N. O. Jensen, A Note on Wind Turbine Interaction, Riso-M-2411 (Risoe National Laboratory, Roskilde 1983), p. 16.
  32. J. Westerweel, C. Fukushima, J. Pedersen, and J. C. R. Hunt, Mechanics of the Turbulent-Nonturbulent Interface of a Jet, Phys. Rev. Lett. 95, 174501 (2005).
  33. H. Vollmers, Detection of vortices and quantitative evaluation of their main parameters from experimental velocity data, Meas. Sci. Technol. 12, 1199 (2001).
  34. A. Prasad and C. H. K. Williamson, The instability of the shear layer separating from a bluff body, J. Fluid Mech. 333, 375 (1997).
  35. M. M. Cicolin, Ph.D. thesis, Universidade de São Paulo, 2020 (unpublished).
  36. C. Barbi, D. P. Favier, C. A. Maresca, and D. P. Telionis, Vortex shedding and lock-on of a circular-cylinder in oscillatory flow, J. Fluid Mech. 170, 527 (1986).
  37. E. Konstantinidis and S. Balabani, Symmetric vortex shedding in the near wake of a circular cylinder due to streamwise perturbations, J. Fluids Struct. 23, 1047 (2007).
  38. C. Norberg, Fluctuating lift on a circular cylinder: Review and new measurements, J. Fluids Struct. 17, 57 (2003).
  39. V. L. Okulov, I. V. Naumov, R. F. Mikkelsen, I. K. Kabardin, and J. N. Sørensen, A regular Strouhal number for large-scale instability in the far wake of a rotor, J. Fluid Mech. 747, 369 (2014).
  40. C. J. Apelt and G. S. West, The effects of wake splitter plates on the flow past a circular cylinder in the range 104<R<5×104. Part 2, J. Fluid Mech. 71, 145 (1975).
  41. P. W. Bearman, Investigation of the flow behind a two-dimensional model with a blunt trailing edge fitted with splitter plates, J. Fluid Mech. 21, 241 (1965).
  42. A. Roshko, Experiments on the flow past a circular cylinder at very high Reynolds number, J. Fluid Mech. 10, 345 (1961).

Outline

Information

Phys. Rev. Fluids 8, 034603– Published 13 March, 2023
  • Received 13 September 2022
  • Accepted 6 February 2023
Crossmark - Check for updates button
Creative Commons Logo

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

Published by the American Physical Society

Sign In to Your Journals Account

Filter

Filter

Article Lookup

Enter a citation