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12:00
15 mins
Bulk statistics of stable and decaying Taylor-Couette turbulence
Sander Huisman, Ruben Verschoof, Roeland van der Veen, Chao Sun, Detlef Lohse
Session: Intermittency and scaling 1
Session starts: Tuesday 25 August, 10:30
Presentation starts: 12:00
Room: Room H

Sander Huisman (University of Twente)
Ruben Verschoof (University of Twente)
Roeland van der Veen (University of Twente)
Chao Sun (University of Twente)
Detlef Lohse (University of Twente)

Abstract:
In this talk we focus on the velocity fluctuations in highly turbulent Taylor-Couette flow for the case of stable flow (constant rotation) and for decaying flow. Turbulent flows are generally characterized by the range of scales of their fluctuations, and a statistical description of the flow is often done by calculating the correlations of velocity fluctuations. These correlations are found to behave like power-laws over a range of scales, and their exponents characterize a certain geometry of flow. Many systems have been investigated carefully: Pipe-flow, Von K\'arm\'an flow, Rayleigh B\'enard convection, \textit{et cetera}. There are, however, few reports \cite{lew99,she01} quantifying the turbulent properties in Taylor-Couette flow. In the presented work \cite{huisman2013b} we measure the longitudinal structure functions using laser Doppler anemometry, which is a non-intrusive technique and is able to measure the components of the velocity, and thus ideal for obtaining structure functions and the local velocity. We present the statistics of the turbulent velocity fluctuations for counter rotation for varying $a=-\omega_o/\omega_i$.