OSCILLATIONS OF LIQUID COLUMNS UNDER MICROGRAVITY

In the experiment LICOR (Liquid Columns' Resonances) performed during the D-2 mission axial oscillations of liquid columns under microgravity conditions were investigated. As fluids two types of silicon oil (vicosities 9 cSt and 5 cSt) were used. Cylindrical columns of 30 mm in diameter and a length of 39.7 mm, 41.7, and 49.1 mm respectively were supported by circular disks. In order to excite vibrations of the liquid column one of the disks was oscillated axially. The oscillations of the column were observed by recording their outer shape and by measuring the pressure exerted at the supporting disks. Moreover, terrestrial experiments on small liquid columns were performed. The experimental results were compared with calculations based on two types of theories: first the linearized Navier-Stokes equation combined with appropriate boundary conditions /1,2/ and second a Cosserat model /3-6/. At oscillations of large wavelength both theories and the experiments yield the same results on the resonance frequencies. At smaller wavelength, however, the predictions of both theories differ. The experimental results turned out to be closer to the solutions of the Navier-Stokes equation.