1. Turbulence in the system of two immiscible liquids Petr Denissenko, Sergei Lukaschuk, Sergei Poplavski Laboratory of Fluid Dynamics, The University of Hull

2. Suspensions of immiscible liquids We study Energy spectra of two flows: Flow 1: silicon oil ( =3, =0.88) Flow 2: 80% oil + 20% water-glycerol (60% water, 40% glycerol, =3, =1.1) Surface tension on the oil-mixture interface = 0.04 N/m. Water-glycerol is coloured by fluorescent dye Rhodamine 6G. Additional scale: capilary length Industrial applications: mixing, suspension formation The study was initiated by the work Misha Chertkov, Igor Kolokolov, Vladimir Lebedev, U. of Warwick, September 15, 2005

3. French Washing Machine 9×9×12 cm with Counter-rotating two-blade propellers. CCD camera 2048x2028 pixel adapted from PIV Nd YAG pulsed laser, Green, 532 nm LDA probe Blue, 476 nm LDA green Blue, 514 nm Water-Glycerol mixture visualized by fluorescent dye Rhodamine 6G (yellow) 2-point Velocity measurement by Laser Doppler Anemometer

4. Water-Glycerol (white) mixing with oil (black) image 27 x 27mm Pumping scale L = 60 mm Capillary scale l c = 10 mm Viscous scale = 0.3 mm

7. Same refractive index Same dynamic viscosity Same density (not yet) Refractive index and viscosity (3 10 -3 Pa s) are matched between Silicone Oil and Water-Glycerol phases by adjusting Water-to-Glycerol proportion (40% Glycerol) and the Temperature (37°C). Density may be matched by choosing the composition of Silicone Oil

9. French Washing Machine 9×9×12 cm with Counter-rotating two-blade propellers. CCD camera 2048x2028 pixel adapted from PIV Nd YAG pulsed laser, Green, 532 nm LDA probe Blue, 476 nm LDA green Blue, 514 nm Water-Glycerol mixture visualized by fluorescent dye Rhodamine 6G (yellow) 2-point Velocity measurement by Laser Doppler Anemometer

10. Camera image Droplets chosen for FFT analysis Measurement of droplet size and shape

13. Decomposition of the bubble shape by circular harmonics Mode energy Mode amplitude Mode number Note! We analyze a section, not the 3D shape.

14. 3 rps 4 rps 5 rps 6 rps 8 rps Distribution of droplets by diameter

15. 3 rps 4 rps 5 rps 6 rps 8 rps Distribution of WG volume by droplet diameter Position of maximum

16. Each harmonic at each droplet is assigned the Wavelength, the Frequency, the Energy.

17. E= d 2 Distribution of surface energy by droplet diameter

18. E= 4 n 2 a n 2 Distribution of oscillations energy by droplet diameter

19. Position of maximum in energy distribution by droplet size

20. 3 rps 4 rps 5 rps 6 rps 8 rps

21. Energy of oil droplets versus energy of fluid E 3/5

22. French Washing Machine 9×9×12 cm with Counter-rotating two-blade propellers. CCD camera 2048x2028 pixel adapted from PIV Nd YAG pulsed laser, Green, 532 nm LDA probe Blue, 476 nm LDA green Blue, 514 nm Water-Glycerol mixture visualized by fluorescent dye Rhodamine 6G (yellow) 2-point Velocity measurement by Laser Doppler Anemometer

23. Laser Doppler Anemometry Moving particle crosses the interference pattern on the intersection of laser beams. Modulation of reflected light gives the particle velocity...................... Problems: Laser beams are deflected Particles are leaving the fluid volume to the droplet surface.........

24. .......................

25. -4 6 rps 5 rps 4 rps 3 rps Thick lines: oil only Thin lines: oil and Water-Glycerol mixture LDA measurement of energy spectrum in single-phase and two-phase flows

26. LDA measurements: energy spectrum in pure oil and in oil + 20% Water-Glycerol mixture V/l c

27. Two-point measurements: velocity correlation in pure oil and with 20% of Water-Glycerol mixture Distance between probes, mm Correlation coefficient

28. Summary Suspension of two immiscible liquids of a similar viscosity is studied. Droplet shapes are resolved within the suspension. LDA measurements are conducted within the suspension. Distribution of droplet size and energy spectra of droplet oscillations are measured. Distorsion of energy spectra of fluid motion due to capillary effects is detected. Ratio of surface energy to kinetic energy is measured. Future plans Match the fluid densities. Resolve the spectra below capillary scale. Perform the two-point LDA measurement of structure functions.