Gas Motion in a Vibrated Liquid-Filled Cantilevered Tube

When a closed tube containing liquid and gas is vibrated vertically, stable gas regions can form at the upper and lower ends. Acrylic tubes of 10 cm height and 1.27-2.54 cm diameter are filled with 20-cSt silicone oil and ~10% air and then vibrated vertically at 100-600 Hz and 20-40 G. Large lower gas regions are observed in experiments at conditions for which the downward vibration-induced Bjerknes force on bubbles is too small relative to the upward buoyancy force to allow these lower gas regions to form. The possibility that downward bubble motion is enhanced by lateral vibration caused by cantilever motion of the tube is assessed. This effect is shown to be small unless the driving frequency is close to the cantilever frequency. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-NA0003525. This paper describes objective technical results and analysis. Any subjective views or opinions that might be expressed in the paper do not necessarily represent the views of the U.S. Department of Energy or the United States Government.