spatial evolution of wall-imposed disturbance in pipe flow
DESCRIPTION
Spatial evolution of wall-imposed disturbance in pipe flow. Cas van Doorne, 1 Jerry Westerweel, 1 Frans Nieuwstadt ( †) , Tobias Schneider 2 & Bruno Eckhardt 2 1 Laboratory for Aero & Hydrodynamics, Delft University of Technology The Netherlands - PowerPoint PPT PresentationTRANSCRIPT
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Spatial evolution of wall-imposed disturbance in pipe flow
Cas van Doorne,1 Jerry Westerweel,1 Frans Nieuwstadt (†), Tobias Schneider2 & Bruno Eckhardt2
1Laboratory for Aero & Hydrodynamics, Delft University of TechnologyThe Netherlands2Fachbereich Physik, University of Marburg, Germany
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Motivation
• Transition in pipe flow has remained an unresolved problem (Reynolds 1883)
• Experimental validation of the transition scenario (e.g., DNS by Ma Bing et al. 1999)
• What is the nature of the boundary between laminar and turbulent flow? (Edge of Chaos, Skufka et al. 2006)
• Turbulence control?
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Laminar disturbance mechanism
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Stereo PIV: optical configuration
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Stereo PIV
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The edge of chaos
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Numerical edge trajectory
Skufka, Yorke, Eckhardt, PRL 96 (2006) 174101
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Edge state structure: off-center jet
Experiment Numerical simulation
Re = 2875Re = 3000
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LIF visualization
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z / D = 3.0
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z / D = 5.0
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z / D = 8.1
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z / D = 11.3
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z / D = 14.4
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Fully developed turbulence
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Reconstructed vorticity
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Spectral mode decomposition
DNS S-PIV
Re = 3000, 0.25 Hz
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Conclusions
• Flow transition induced by laminar disturbance mechanism
• High-precision S-PIV set-up for measuring cross-flow• Disturbance mimics the edge of chaos flow structure • Quantitative measurement of development of
streaks into packets of hairpin vortices
• Next: add second disturbance mechanism to achieve flow control in experimental configuration