1. Water Drops and Cavitation Bubbles in Microgravity 56th International Astronautical Congress 17th October 2005, Fukuoka, Japan D. Obreschkow, P. Kobel, N. Dorsaz, A. de Bosset, C. Nicollier, and M. Farhat

3. About cavitation Cavitation bubbles Implosion phenomena Concerned technologies Damage

4. Goal Confined shockwave Observe all liquid jets Interaction with spherical free surface Water Drop Cavitation Bubble

5. Here we go !

6. Part I Water Drop

7. Drop Formation & Fixation

8. Drop Growth 10 mm

9. Drop Oscillations 1/e damp out time = 0.7s

10. Drop-Electrodes Interaction Negligible interaction Repulsion by electrodes Attraction by electrodes

11. Part II Cavitation Bubble

12. It’s really fast !

13. Close-up

14. Stability of Drop and Free Surface

15. Counterjet Geometry Planar free surface (ground experiment) Spherical free surface (microgravity experiment) bubble [Robinson et al. 01] Free Surface High pressure Numerical Simulation

16. Shockwave-Nuclei Interaction 0.0ms0.08ms0.16ms Shockwave Energy Potential Energy Evidence for “Hairjets” = 0.95 (± 0.1)

17. Implosion Process Modified Rayleigh-Plesset equation (empty bubble): R b (t) R d (t)

18. Conclusions Direct Observation of Jet-Pair Counterjet Geometry Change Shockwave Confinement Shockwave Energy Measurement Stable Water Drop Formation Damp Out Oscillations FOLLOW-UP IDEAS: Polarized Light (Schlieren) ! Higher time/space resolution Smaller area of support

19. FLASH & SPLASH !

20. Appendix

21. Flight Maneuver

22. Global Evolution

23. Bubble inside extended volume on ground Rayleigh-Plesset equation (empty bubble)