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Near and Far-Field Analysis of an Axisymmetric Fractal-Forced Turbulent Jet

  • Massimiliano BredaEmail author
  • Oliver R. H. Buxton
Conference paper
Part of the Springer Proceedings in Physics book series (SPPHY, volume 196)

Abstract

In this paper, the role of the initial conditions in affecting the flow physics in the near-field, and the evolution towards self-similarity, of an axisymmetric turbulent jet is examined. The near-field large scale coherent structures are manipulated with the aid of noncircular geometries, such as square and fractal exits. Planar PIV and hot-wire anemometry are deployed to study the flow both spatially and temporally. Despite the significant alteration of the near-field flow physics due to the different exit geometries, it is found that the evolution towards self-similarity is comparable between all jets. Moreover, non-equilibrium dissipation is found between 24 and 26 equivalent diameters \(D_e\) downstream of the jet exit where mean velocity and Reynolds stresses are self-similar, suggesting the microscales of the flow take much further than previously thought to regain the classical scaling laws.

References

  1. 1.
    R.A. Antonia, B. Pearson, Effect of initial conditions on the mean energy dissipation rate and the scaling exponent. Phys. Rev. E 62(6), 8086–8090 (2000)CrossRefGoogle Scholar
  2. 2.
    R.A. Antonia, Q. Zhao, Effect of initial conditions on a circular jet. Exp. Fluids 31(3), 319–323 (2001)CrossRefGoogle Scholar
  3. 3.
    W.K. George, The self-preservation of turbulent flows and its relation to initial conditions and coherent structures. Technical report, University at Buffalo, Buffalo, New York, USA (1989)Google Scholar
  4. 4.
    S. Goto, J.C. Vassilicos, Energy dissipation and flux laws for unsteady turbulence. Phys. Lett. Sect. A: Gen. At. Solid State Phys. 379(16–17), 1144–1148 (2015)CrossRefGoogle Scholar
  5. 5.
    E. Gutmark, F.F. Grinstein, Flow control with noncircular jets. Annu. Rev. Fluid Mech. 31, 239–272 (1999)CrossRefGoogle Scholar
  6. 6.
    R.J. Hearst, P. Lavoie, Decay of turbulence generated by a square-fractal-element grid. J. Fluid Mech. 741, 567–584 (2014)CrossRefGoogle Scholar
  7. 7.
    J. Nedić, O. Supponen, B. Ganapathisubramani, J.C. Vassilicos, Geometrical influence on vortex shedding in turbulent axisymmetric wakes. Phys. Fluids 27, 035103 (2015)CrossRefGoogle Scholar
  8. 8.
    J. Nedić, J.C. Vassilicos, B. Ganapathisubramani, Axisymmetric turbulent wakes with new nonequilibrium similarity scalings. Phys. Rev. Lett. 111, 144503 (2013)CrossRefGoogle Scholar
  9. 9.
    T. Shakouchi, S. Iriyama, Flow characteristics of submerged free jet flow from petal-shaped nozzle, in 4th International Conference on Jets, Wakes and Separated Flows (2013)Google Scholar
  10. 10.
    A.A.R. Townsend, The Structure of Turbulent Shear Flow, 2nd edn. (Cambridge University Press, New York, 1976)zbMATHGoogle Scholar
  11. 11.
    M. van Reeuwijk, J. Craske, Energy-consistent entrainment relations for jets and plumes. J. Fluid Mech. 782, 333–355 (2015)MathSciNetCrossRefGoogle Scholar
  12. 12.
    J.C. Vassilicos, Dissipation in turbulent flows. Annu. Rev. Fluid Mech. 47, 95–114 (2015)CrossRefGoogle Scholar

Copyright information

© Springer International Publishing AG 2017

Authors and Affiliations

  1. 1.Imperial College LondonLondonUK

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