Taylor bubble rising in a vertical pipe against laminar or turbulent downward flow: symmetric to asymmetric shape transition

摘要

The symmetry of Taylor bubbles moving in a vertical pipe is likely to break when the liquid flows downward at a velocity greater than some critical value. The present experiments performed in the inertial regime for Reynolds numbers in the range 100< Re < 10 000 show that bifurcation to an eccentric motion occurs, with a noticeable increase of the bubble velocity. The influence of the surface tension parameter (an inverse E?tv?s number), ∑, has been investigated for 0.0045< ∑ <0.067. It appears that the motion of an asymmetric bubble is much more sensitive to surface tension than that of a symmetric bubble. For any given ∑, the symmetry-breaking bifurcation occurs in both laminar and turbulent flow at the same vorticity-to-radius ratio (ω/r)_0 on the axis of the carrier fluid. This conclusion also applies to results obtained previously from numerical experiments in plane flows.