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

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?

Laminar disturbance mechanism

Stereo PIV: optical configuration

Stereo PIV

The edge of chaos

Numerical edge trajectory

Skufka, Yorke, Eckhardt, PRL 96 (2006) 174101

Edge state structure: off-center jet

Experiment Numerical simulation

Re = 2875Re = 3000

LIF visualization

z / D = 3.0

z / D = 5.0

z / D = 8.1

z / D = 11.3

z / D = 14.4

Fully developed turbulence

Reconstructed vorticity

Spectral mode decomposition

DNS S-PIV

Re = 3000, 0.25 Hz

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