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Experimental Analysis of Liquid Bridge Breakage in Microgravity

Investigating the breakage of a liquid bridge under microgravity conditions using experimental methods and image analysis. The study examines the stability and dynamics of liquid columns in space, presenting findings and challenges encountered during the research.

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Experimental Analysis of Liquid Bridge Breakage in Microgravity

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  1. Experimental analysis of the breakage of a liquid bridge under microgravity conditions I. Martínez, J.M. Perales Universidad Politécnica de Madrid, Spain COSPAR 2010 Thursday, 22ndJuly2010

  2. Spacelab-D2, Experiment“STACO”, Run 2

  3. Experimentdescription • ExperimentperformedonboardSpacelab D-2 (1993) with AFPM. • Fluid used: siliconeoil of n=10 cSt, r=920 kg/m3, s=0.020 N/m. • Supports: two 30 mm in diametercircular coaxial disks made of aluminiumblack-anodized, with a 30º dove-tailcut back. • Nominal shape: cylindricalliquidcolumnwithL=85 mm length. • Diffuse white background illumination (9·8 leds). • Ref.: • Martínez, I., Perales, J.M., Meseguer, J., Stability of long liquid columns (SL-D2-FPM-STACO), in Scientific Results of the German Spacelab Mission D-2, Ed. Sahm, P.R., Keller, M.H., Schiewe, B, WPF, pp. 220-231, 1995. • Martínez, I., http://webserver.dmt.upm.es/~isidoro/lc1/SL/ST2_118_13_30_41stretch_xvid.avi

  4. Automated image edging

  5. Stabilitydiagramforunloadedliquid bridgesStretchingevolution at constantvolumefrom A to B

  6. Experimental values (length, volume, stability)

  7. Non-dimensionalization

  8. Columnshapesand theirstability (nondimensional) • Equilibriumshapeswithv<<1 (linearized) and L~π • Dynamicshapes (firsteigenfunction) • Stabilitylimit

  9. Fittingtheliquidshapewith 1-, 2-, 3-terms

  10. Evolution of thefirstsine term (a) and cosineterm (b)

  11. Neckingdynamics

  12. Stabilitymargin

  13. Linear inviscid stable and unstable response

  14. Diverging amplitude (amphora-type deformation)

  15. Conclusions • Non-linear dynamic simulation of the breaking process has yield a perfect matching with experimental results, which linear theories did not achieve. • Many small details in the experimental results are still unexplained (e.g. the lack of decay in the small free oscillations; g-jitter?). • Automated image analysis has progressed a lot, but small problems remain (full image analysis helps a lot, but details of the discs are not visible). • Digital imaging nowadays would solve many of the old video problems. • Actual liquid column in space appear always oscillating (microgravity): • Around an equilibrium shape that is unexpected (a residual load shows up) • With a small but non-decaying amplitude (0.3 mm peak-to-peak) • With a frequency very close to the first natural frequency (axial, and lateral). • Useful experimental time in space is always very scarce (e.g. a couple of minutes in half an hour, here). • Unique experiments may have some unknown boundary conditions (repetition is a must, but these experiments have not been reproduced yet).

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