Periodically driven Taylor-Couette turbulence

Ruben A. Verschoof, Arne K. te Nijenhuis, Sander G. Huisman, Chao Sun* (Corresponding Author), Detlef Lohse

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

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Abstract

We study periodically driven Taylor-Couette turbulence, i.e. the flow confined between two concentric, independently rotating cylinders. Here, the inner cylinder is driven sinusoidally while the outer cylinder is kept at rest (time-averaged Reynolds number is Rei = 5 × 105). Using particle image velocimetry, we measure the velocity over a wide range of modulation periods, corresponding to a change in Womersley number in the range 15 ≤ Wo ≤ 114. To understand how the flow responds to a given modulation, we calculate the phase delay and amplitude response of the azimuthal velocity. In agreement with earlier theoretical and numerical work, we find that for large modulation periods the system follows the given modulation of the driving, i.e. the behaviour of the system is quasi-stationary. For smaller modulation periods, the flow cannot follow the modulation, and the flow velocity responds with a phase delay and a smaller amplitude response to the given modulation. If we compare our results with numerical and theoretical results for the laminar case, we find that the scalings of the phase delay and the amplitude response are similar. However, the local response in the bulk of the flow is independent of the distance to the modulated boundary. Apparently, the turbulent mixing is strong enough to prevent the flow from having radius-dependent responses to the given modulation.

Original languageEnglish
Pages (from-to)834-845
Number of pages12
JournalJournal of fluid mechanics
Volume846
DOIs
Publication statusPublished - 10 May 2018

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Keywords

  • UT-Hybrid-D
  • Taylor-Couette flow
  • Turbulent flows
  • Rotating turbulence

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