Transitional and Turbulent Bent Pipes

  • Philipp SchlatterEmail author
  • Azad Noorani
  • Jacopo Canton
  • Lorenz Hufnagel
  • Ramis Örlü
  • Oana Marin
  • Elia Merzari
Conference paper
Part of the Springer Proceedings in Physics book series (SPPHY, volume 196)


We review a number of aspects of the transitional and turbulent flow in bent pipes, obtained at KTH using the spectral-element code Nek5000. This flow, sometimes also called Dean flow, is characterised by the appearance of Dean vortices, which arise due to the action of the centrifugal force in the bend. We start with reviewing recent stability analysis in the toroidal flow, and conclude that for all curvatures \(\delta >0\) an exponential instability is present at a bulk Reynolds number of about 4000. Further increasing the Reynolds number lets the flow go through a region with potential sub straight and sublaminar drag. An analysis using proper orthogonal decomposition (POD) reveals that wave-like motions are still present in the otherwise turbulent flow. Upon further increasing Re, the in-plane Dean vortices lead to a modulation of turbulence depending on the azimuthal position. The flow is then dominated by low-frequency so-called swirl-switching motion. This motion is studied in both a periodic and spatially developing framework. Finally, the effect of Dean vortices on Lagrangian inertial particles is studied.



Financial support by the Swedish Research Council (VR) and the Knut and Alice Wallenberg Foundation (KAW) is gratefully acknowledged. Most of the simulations were performed on resources provided by the Swedish National Infrastructure for Computing (SNIC) at the National Supercomputer Centre (NSC) and PDC (Stockholm). Additional simulations were performed within the DECI-project PIPETURB.


  1. 1.
    A. Noorani, P. Schlatter, Swirl-switching phenomenon in turbulent flow through toroidal pipes. Int. J. Heat Fluid Flow 61, 108–116 (2016)CrossRefGoogle Scholar
  2. 2.
    L. Hufnagel, On the swirl switching in developing bent pipe flow with direct numerical simulation, Master’s Thesis, KTH Mechanics, 2016Google Scholar
  3. 3.
    A. Kalpakli Vester, R. Örlü, P.H. Alfredsson, Turbulent flows in curved pipes: recent advances in experiments and simulations. Appl. Mech. Rev. 68(5), 050802 (2016)CrossRefGoogle Scholar
  4. 4.
    G.K. El Khoury, P. Schlatter, A. Noorani, P.F. Fischer, G. Brethouwer, A.V. Johansson, Direct numerical simulation of turbulent pipe flow at moderately high Reynolds number. Flow Turbul. Combust. 91, 475–495 (2013)CrossRefGoogle Scholar
  5. 5.
    P.F. Fischer, J.W. Lottes, S.G. Kerkemeier, Nek5000 Web page, 2008,
  6. 6.
    A. Noorani, G.K. El Khoury, P. Schlatter, Evolution of turbulence characteristics from straight to curved pipes. Int. J. Heat Fluid Flow 41, 16–26 (2013)CrossRefGoogle Scholar
  7. 7.
    J. Canton, Global linear stability of axisymmetric coaxial jets, Master’s Thesis, Politecnico di Milano, 2013Google Scholar
  8. 8.
    J. Canton, R. Örlü, P. Schlatter, Characterisation of the steady, laminar incompressible flow in toroidal pipes covering the entire curvature range, submitted (2017)Google Scholar
  9. 9.
    J. Canton, P. Schlatter, R. Örlü, Modal instability of the flow in a toroidal pipe. J. Fluid Mech. 792, 894–909 (2016)MathSciNetCrossRefGoogle Scholar
  10. 10.
    A. Noorani, G. Sardina, L. Brandt, P. Schlatter, Particle velocity and acceleration in turbulent bent pipe flows. Flow Turbul. Combust. 95(2), 539–559 (2015)CrossRefGoogle Scholar
  11. 11.
    A. Noorani, G. Sardina, L. Brandt, P. Schlatter, Particle transport in turbulent curved pipe flow. J. Fluid Mech. 793, 248–279 (2016)MathSciNetCrossRefGoogle Scholar
  12. 12.
    A. Noorani, P. Schlatter, Evidence of sublaminar drag naturally occurring in a curved pipe. Phys. Fluids 27, 035105 (2015)CrossRefGoogle Scholar
  13. 13.
    C. Brücker, A time-recording DPIV-study of the swirl switching effect in a 90\(^\circ \) bend flow. 8th International Symposium on Flow Visualization, Sorrento, Italy p. 171 (1998)Google Scholar
  14. 14.
    N. Jarrin, S. Benhamadouche, D. Laurence, R. Prosser, A synthetic eddy-method for generating inflow conditions for large-eddy simulations. Int. J. Heat Fluid Flow 27(4), 585–593 (2006)CrossRefzbMATHGoogle Scholar

Copyright information

© Springer International Publishing AG 2017

Authors and Affiliations

  • Philipp Schlatter
    • 1
    Email author
  • Azad Noorani
    • 1
  • Jacopo Canton
    • 1
  • Lorenz Hufnagel
    • 1
  • Ramis Örlü
    • 1
  • Oana Marin
    • 2
  • Elia Merzari
    • 2
  1. 1.Linné FLOW Centre, KTH MechanicsStockholmSweden
  2. 2.MCSArgonne National Laboratory LemontUSA

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