Motion Measurement of Rising Bubble Trains in Cylindrical Pipe

Instabilities of cylindrical bubble clusters.

Small bubbles in an experimental two-dimensional foam between glass plates regularly undergo a three-dimensional instability as the small bubbles shrink under diffusion or equivalently as the plate separation increases, and end up on one of the plates. The most recent experiments of Cox, Weaire, and Vaz are accompanied by Surface Evolver computer simulations and rough theoretical calculations. ...

Computational Simulation of Hydrodynamic Convection in Rising Bubble Under Microgravity Condition

In this work, rising of a single bubble in a quiescent liquid under microgravity condition was simulated. The related unsteady incompressible full Navier-Stokes equations were solved using a conventional finite difference method with a structured staggered grid. The interface was tracked explicitly by connected marker points via hybrid front capturing and tracking method. One field approximatio...

Slug genesis in cylindrical pipe flow

Transition to uniform turbulence in cylindrical pipe flow occurs experimentally via the spatial expansion of isolated coherent structures called ‘slugs’, triggered by localised finite-amplitude disturbances. We study this process numerically by examining the preferred route in phase space through which a critical disturbance initiates a ‘slug’. This entails first identifying the relative attrac...

A Bubble Rising in Viscous Fluid: Lagrange’s Equations for Motion at a High Reynolds Number

A gas bubble rising steadily in a pure liquid otherwise at rest at a moderate Weber number is, to a good approximation, of oblate spheroidal shape. Previous analytical calculations of that shape at high Reynolds numbers have ignored viscosity. This paper shows that if one includes viscosity by incorporating Rayleigh’s dissipation integral in Lagrange’s equations, then the speed of rise is that ...

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