Uncovering large-scale coherent structures in natural and forced turbulent wakes by combining PIV, POD, and FTLE

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Planar velocity data of the unsteady separated flow in the turbulent wake of a circular cylinder obtained by particle image velocimetry (PIV) are analyzed in order to visualize the large-scale coherent structures associated with alternating vortex shedding at a Reynolds number of 2,150. Two different cases are examined: unforced vortex shedding in the natural wake and vortex lock-on incited by forced perturbations superimposed in the inflow velocity. Proper orthogonal decomposition (POD) is employed to reconstruct the low-order wake dynamics from randomly sampled snapshots of the velocity field. The reconstructed flow is subsequently used to determine the evolution of the finite-time Lyapunov exponent (FTLE) fields which identify the Lagrangian coherent structures. The results demonstrate that the combination of methods employed offers a powerful visualization tool to uncover large-scale coherent structures and to exemplify vortex dynamics in natural and forced bluff-body wakes.

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  1. Cantwell B, Coles D (1983) An experimental-study of entrainment and transport in the turbulent near wake of a circular-cylinder. J Fluid Mech 136:321–374

  2. Choi H, Jeon WP, Kim J (2008) Control of flow over a bluff body. Ann Rev Fluid Mech 40:113–139

  3. Cimbala JM, Nagib HM, Roshko A (1988) Large structure in the far wakes of two-dimensional bluff bodies. J Fluid Mech 190:265–298

  4. Epps BP, Techet AH (2010) An error threshold criterion for singular value decomposition modes extracted from PIV data. Exp Fluids 48:355–367

  5. Gerrard JH (1966) The mechanics of the formation region of the vortices behind bluff bodies. J Fluid Mech 25:401–413

  6. Griffin OM, Hall HS (1991) Review—vortex shedding lock-on and flow control in bluff body wakes. J Fluids Eng 113:283–291

  7. Griffin OM, Ramberg SE (1976) Vortex shedding from a cylinder vibrating in line with an incident uniform flow. J Fluid Mech 75:526–537

  8. Haller G (2002) Lagrangian coherent structures from approximate velocity data. Phys Fluids 14:1851–1861

  9. Huera-Huarte FJ, Vernet A (2010) Vortex modes in the wake of an oscillating long flexible cylinder combining POD and fuzzy clustering. Exp Fluids 48:999–1013

  10. Kim W, Yoo JY, Sung J (2006) Dynamics of vortex lock-on in a perturbed cylinder wake. Phys Fluids 18:074103

  11. Konstantinidis E, Balabani S (2008) Flow structure in the locked-on wake of a circular cylinder in pulsating flow: effect of forcing amplitude. Int J Heat Fluid Flow 29:1567–1576

  12. Konstantinidis E, Balabani S, Yianneskis M (2003) The effect of flow perturbations on the near wake characteristics of a circular cylinder. J Fluid Struct 18:367–386

  13. Konstantinidis E, Balabani S, Yianneskis M (2005) Conditional averaging of PIV plane wake data using a cross-correlation approach. Exp Fluids 39:38–47

  14. Konstantinids E, Balabani S, Yianneskis M (2007) Bimodal vortex shedding in a perturbed cylinder wake. Phys Fluids 19:011701

  15. Lekien F (2007) MANGEN. Accessed 25 Nov 2007

  16. Lin J-C, Vorobieff P, Rockwell D (1995) Three-dimensional patterns of streamwise vorticity in the turbulent near wake of a cylinder. J Fluids Struct 9:231–234

  17. Lourenco L, Subramanian S, Ding Z (1997) Time series velocity field reconstruction from PIV data. Meas Sci Technol 8:1533–1538

  18. Lyn DA, Einav S, Rodi W, Park J-H (1995) A laser-Doppler velocimetrystudy of ensemble-averaged characteristics of turbulent near wake of a square cylinder. J Fluid Mech 304:285–319

  19. Ma X, Karamanos GS, Karniadakis GE (2000) Dynamics and low dimensionality of a turbulent near wake. J Fluid Mech 410:29–65

  20. Ma X, Karniadakis GE, Park H, Gharib M (2003) DPIV-driven flow simulation: a new computational paradigm. Proc R Soc London (Ser A) 459:547–565

  21. Monkewitz PA, Huerre P, Chomaz JM (1993) Global linear-stability analysis of weakly nonparallel shear flows. J Fluid Mech 251:1–20

  22. Olcay AB, Krueger PS (2008) Measurement of ambient fluid entrainment during laminar vortex ring formation. Exp Fluids 44:235–247

  23. Perret L, Collin E, Deville J (2006) Polynomial identification of POD based low-order dynamical system. J Turb 7(17):1–15

  24. Perry AE, Chong MS, Lim TT (1982) The vortex-shedding process behind two-dimensional bluff bodies. J Fluid Mech 116:77–90

  25. Roushan P, Wu XL (2005) Universal wake structures of Kármán vortex streets in two-dimensional flows. Phys Fluids 17:073601

  26. Scarano F, Poelma C (2009) Three-dimensional vorticity patterns of cylinder wakes. Exp Fluids 47:69–83

  27. Shadden SC, Lekien F, Marsden JE (2005) Definition and properties of Lagrangian coherent structures from finite-time Lyapunov exponents in two-dimensional aperiodic flow. Physica D 212:271–304

  28. Shadden SC, Dabiri JO, Marsden JE (2006) Lagrangian analysis of fluid transport in empirical vortex ring flows. Phys Fluids 18:047105

  29. Sirovich L (1987) Turbulence and the dynamics of coherent structures. Q Appl Math 45:561–590

  30. Sung J, Yoo JY (2001) Three-dimensional phase averaging of time resolved PIV measurement data. Meas Sci Technol 12:655–662

  31. van Oudheusden BW, Scarano F, van Hinsberg NP, Watt DW (2005) Phase-resolved characterization of vortex shedding in the near wake of a square-section cylinder at incidence. Exp Fluids 39:86–98

  32. Williamson CHK (1996) Vortex dynamics in the cylinder wake. Ann Rev Fluid Mech 28:477–539

  33. Zdravkovich MM (1997) Flow around circular cylinders, vol 1: fundamentals. Oxford University Press, Oxford, UK, ISBN 0-19-856396-5

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Correspondence to E. Konstantinidis.

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Kourentis, L., Konstantinidis, E. Uncovering large-scale coherent structures in natural and forced turbulent wakes by combining PIV, POD, and FTLE. Exp Fluids 52, 749–763 (2012).

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  • Vortex
  • Particle Image Velocimetry
  • Coherent Structure
  • Proper Orthogonal Decomposition
  • Proper Orthogonal Decomposition Mode