Transitional and turbulent bent pipes

Philipp Schlatter, Azad Noorani, Jacopo Canton, Lorenz Hufnagel, Ramis Örlü, Oana Marin, Elia Merzari

Research output: Chapter in Book/Report/Conference proceedingConference contribution


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 δ>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.

Original languageEnglish (US)
Title of host publicationProgress in Turbulence VII - Proceedings of the iTi Conference in Turbulence 2016
EditorsRamis Orlu, Alessandro Talamelli, Martin Oberlack, Joachim Peinke
PublisherSpringer Science and Business Media, LLC
Number of pages7
ISBN (Print)9783319579337
StatePublished - 2017
Event7th iTi Conference on Turbulence, 2016 - Bertinoro, Italy
Duration: Sep 7 2016Sep 9 2016

Publication series

NameSpringer Proceedings in Physics
ISSN (Print)0930-8989
ISSN (Electronic)1867-4941


Conference7th iTi Conference on Turbulence, 2016

All Science Journal Classification (ASJC) codes

  • General Physics and Astronomy


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