Advertisement

Wake Dynamics of External Flow Past a Curved Circular Cylinder with the Free-Stream Aligned to the Plane of Curvature

  • A. de VecchiEmail author
  • S.J. Sherwin
  • J.M.R. Graham
Part of the IUTAM Bookseries book series (IUTAMBOOK, volume 14)

Abstract

The fundamental mechanism of vortex shedding past a curved cylinder has been investigated at a Reynolds number of 100 using three-dimensional spectral/hp computations. Two different configurations are presented herein:in both cases the main component of the geometry is a circular cylinder whose centreline is a quarter of a ring and the inflow direction is parallel to the plane of curvature.

In the first set of simulations the cylinder is forced to transversely oscillate at a fixed amplitude, while the oscillation frequency has been varied around the Strouhal value. Both geometries exhibit in-phase vortex shedding, with the vortex cores bent according to the body's curvature, although the wake topology is markedly different. In particular, the configuration that was found to suppress the vortex shedding in absence of forced motion exhibits now a primary instability in the near wake. A second set of simulations has been performed imposing an oscillatory roll to the curved cylinder, which is forced to rotate transversely around the axis of its bottom section. This case shows entirely different wake features from the previous one: the vortex shedding appears to be out-of-phase along the body's span, with straight cores that tend to twist after being shed and manifest a secondary spanwise instability. Further, the damping effect stemming from the transverse planar motion of the part of the cylinder parallel to the flow is no longer present, leading to a positive energy transfer from the fluid to the structure.

Keywords

Vortex shedding Bluff bodies Vortex-induced vibration 

Notes

Acknowledgments

A. de Vecchi would like to acknowledge the Engineering and Physical Sciences Research Council (UK) who supports her position. This work has been carried out in the research group on Vortex flows of the Department of Aeronautics at Imperial College on the basis of CPU allocations of the computer facilities in the ICT cluster of Imperial College.

References

  1. 1.
    Eisenlohr, H., Ecklemann, H., 1989. Vortex splitting and its consequences in the vortex street wake of cylinders at low reynolds number. Physics of Fluids A1, 189–192.Google Scholar
  2. 2.
    Williamson, C., 1989. Vortex shedding in the wake of a circular cylinder at low reynolds numbers. Journal of Fluid Mechanics 206, 579–627.CrossRefADSGoogle Scholar
  3. 3.
    Takamoto, M., Izumi, K., 1981. Experimental observation of stable arrangement of vortex rings. Physics of Fluids 24, 1582–1583.CrossRefADSGoogle Scholar
  4. 4.
    Leweke, T., Provansal, M., 1995. The flow behind rings — bluff-body wakes without end effects. Journal of Fluid Mechanics 288, 265–310.CrossRefADSGoogle Scholar
  5. 5.
    Miliou, A., Sherwin, S., Graham, J., 2003. Fluid dynamic loading on curved riser pipes. ASME Journal of Offshore Mechanics and Arctic Engineering 125, 176–182.CrossRefGoogle Scholar
  6. 6.
    Miliou, A., de Vecchi, A., Sherwin, S. J., Graham, J. M. R., 2007. Wake dynamics of external flow past a curved cylinder with the free-stream aligned to the plane of curvature. Journal of Fluid Mechanics 592, 89–115.zbMATHCrossRefADSGoogle Scholar
  7. 7.
    Darekar, R. M., Sherwin, S. J., 2001. Flow past a square-section cylinder with a wavy stagnation face. Journal of Fluid Mechanics 426, 263–295.zbMATHCrossRefADSGoogle Scholar
  8. 8.
    Bearman, P., Owen, J., 1998. Reduction of bluff-body drag and suppression of vortex shedding by the introduction of wavy separation lines. Journal of Fluid and Structures 12, 123–130.CrossRefADSGoogle Scholar
  9. 9.
    Bearman, P., Tombazis, N., 1997. A study of the three-dimesional aspects of vortex shedding from a bluff body with a mild geometric disturbance. Journal of Fluid Mechanics 330, 85–112.CrossRefADSGoogle Scholar
  10. 10.
    Williamson, C., Roshko, A., 1988. Vortex formation in the near wake of an oscillating cylinder. Journal of Fluids and Structures 2, 355–381.CrossRefADSGoogle Scholar
  11. 11.
    Leontini, J., Stewart, B., Thompson, M., Hourigan, K., 2006. Wake state and energy transitions of an oscillating cylinder at low reynolds number. Physics of Fluids 18, 067101, 1–9.MathSciNetGoogle Scholar
  12. 12.
    Kaiktsis, L., Triantafyllou, G., Ozbas, M., 2007. Excitation, inertia, and drag forces on a cylinder vibrating transversely to a steady flow. Journal of Fluids and Structures 23, 1–21.CrossRefADSGoogle Scholar
  13. 13.
    Carberry, J., Govardhan, R., Sheridan, J., Rockwell, D., Williamson, C., 2004. Wake states and response branches of forced and freely oscillating cylinders. European Journal of Mechanics, B23, 89–97.CrossRefADSGoogle Scholar
  14. 14.
    Carberry, J., Sheridan, J., Rockwell, D., 2005. Controlled oscillations of a cylinder: forces and wake modes. Journal of Fluid Mechanics 538, 31–69.zbMATHCrossRefADSGoogle Scholar
  15. 15.
    Meneghini, J., Bearman, P., 1995. Numerical simulations of high amplitude oscillatory flow about a circular cylinder. Journal of Fluids and Structures 9, 435–455.CrossRefADSGoogle Scholar
  16. 16.
    Blackburn, H., Henderson, R., 1999. A study of two-dimensional flow past an oscillating cylinder. Journal of Fluid Mechanics 385, 255–286.zbMATHCrossRefMathSciNetADSGoogle Scholar
  17. 17.
    Al Jamal, H., Dalton, C., 2005. The contrast in phase angles between forced and self-excited oscillations of a circular cylinde. Journal of Fluid and Structures 20, 467–482.CrossRefADSGoogle Scholar
  18. 18.
    Sherwin, S., Karniadakis, G., 1996. Tetrahedral hp finite elements: algorithms and flow simulations. Journal of Computational Physics 124, 14–45.zbMATHCrossRefMathSciNetADSGoogle Scholar
  19. 19.
    Karniadakis, G. E., Sherwin, S. J., 2005. Spectral/hp Element Methods for CFD. Oxford University Press, Oxford.CrossRefGoogle Scholar
  20. 20.
    Karniadakis, G. E., Israeli, M., Orszag, S. A., 1991. High-order splitting methods for the incompressible Navier—Stokes equations. Journal of Computational Physics 97, 414–443.zbMATHCrossRefMathSciNetADSGoogle Scholar
  21. 21.
    Bearman, P., Obasaju, E., 1982. An experimental study of pressure fluctuations on fixed and oscillating square-section cylinders. Journal of Fluid Mechanics 119, 297–321.CrossRefADSGoogle Scholar
  22. 22.
    Bearman, P., 1984. Vortex shedding from oscillating bluff bodies. Annual Review of Fluid Mechanics 16, 195–222.CrossRefADSGoogle Scholar

Copyright information

© Springer Science+Business Media B.V. 2009

Authors and Affiliations

  1. 1.Department of AeronauticsImperial College LondonLondonUK

Personalised recommendations