Transitional and turbulent bent pipes

Schlatter P, Noorani A, Canton J, Hufnagel L, Orlu R, Marin O, Merzari E (2017)


Publication Type: Conference contribution

Publication year: 2017

Publisher: Springer Science and Business Media, LLC

Book Volume: 196

Pages Range: 81-87

Conference Proceedings Title: Springer Proceedings in Physics

Event location: Bertinoro, ITA

ISBN: 9783319579337

DOI: 10.1007/978-3-319-57934-4_12

Abstract

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.

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APA:

Schlatter, P., Noorani, A., Canton, J., Hufnagel, L., Orlu, R., Marin, O., & Merzari, E. (2017). Transitional and turbulent bent pipes. In Ramis Orlu, Alessandro Talamelli, Martin Oberlack, Joachim Peinke (Eds.), Springer Proceedings in Physics (pp. 81-87). Bertinoro, ITA: Springer Science and Business Media, LLC.

MLA:

Schlatter, Philipp, et al. "Transitional and turbulent bent pipes." Proceedings of the 7th iTi Conference on Turbulence, 2016, Bertinoro, ITA Ed. Ramis Orlu, Alessandro Talamelli, Martin Oberlack, Joachim Peinke, Springer Science and Business Media, LLC, 2017. 81-87.

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