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Turbulence in the system of two immiscible liquids

This study conducted by Petr Denissenko, Sergei Lukaschuk, and Sergei Poplavski at the Laboratory of Fluid Dynamics, University of Hull, focuses on suspensions of immiscible liquids and their energy spectra. The research includes visualizing the mixing process and measuring droplet sizes and shapes using advanced techniques.

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Turbulence in the system of two immiscible liquids

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

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

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

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

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

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

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

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

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

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

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

  12. Distribution of surface energy by droplet diameter E= spd2

  13. Distribution of oscillations energy by droplet diameter E= 4sp n2an2

  14. Position of maximum in energy distribution by droplet size

  15. 3 rps 4 rps 5 rps 6 rps 8 rps

  16. Energy of oil droplets versus energy of fluid E3/5

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

  18. . . . . . . . . . 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

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

  21. LDA measurements:energy spectrum in pure oil and in oil + 20% Water-Glycerol mixture dV/lc dV/lc

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

  23. 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.

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