Dynamics of phase transition in H2 under high frequency vibrations
Résumé
Can vibrations act in space as an artificial gravity? We investigate here the role of high frequency vibrations to accelerate the dynamics of phase transition of gas and liquid in space. Hydrogen is studied near its critical point (Tc =33 K). Gravity effects are compensated in a high magnetic field gradient as provided by a 10 T superconducting coil. The experiments are performed in the temperature range [0.17 – 1.1] mK from Tc, at critical and off-critical densities. The pattern shows up as interconnected gas-liquid domains or bubbles. When the domain size becomes larger than the viscous boundary layer, growth is accelerated and the domains eventually elongate in the direction perpendicular to the vibration (interconnected pattern case) or align in periodic planes in the same direction perpendicular to vibration (bubble pattern case). We explain the experimental findings by the presence of inertial velocity gradients between the vapor and liquid domains, which favor coalescence and fast domain growth.