1. 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 Technology
The Netherlands
2Fachbereich Physik, University of Marburg, Germany

2. 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?

3. Laminar disturbance mechanism

4. Stereo PIV: optical configuration

5. Stereo PIV

6. The edge of chaos

7. Numerical edge trajectory
Skufka, Yorke, Eckhardt, PRL 96 (2006)

8. Edge state structure: off-center jet
Experiment Numerical simulation
Re = 3000
Re = 2875

9. LIF visualization

10. z / D = 3.0

11. z / D = 5.0

12. z / D = 8.1

13. z / D = 11.3

14. z / D = 14.4

15. Fully developed turbulence

16. Reconstructed vorticity

17. Spectral mode decomposition
Re = 3000, 0.25 Hz
DNS
S-PIV

18. 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