Numerical study on the rising bubbles in a power-law fluid

In the present talk, a single rising bubble and 2 bubbles rising in a Non-Newtonian power-law fluid have been investigated through the direct numerical simulations. An interface capturing method with a continuous function is introduced and the three-dimensional model based on modified VOF method is used to study two-bubble interaction phenomena for both the Newtonian and Non-Newtonian Fluid.

For Newtonian Fluid, bubbles rising in side-by-side configurations are simulated for low and moderate Reynolds number and the results are compared with Legendre et al. (JFM, 2003).

For power-law fluid, shear thinning and shear thickening effects are analyzed. In the present model, the viscous stress is expressed as a function of shear rate. The simulations are conducted with the variation of effective viscosity and initial separations ranging from 3R to 11R, where R is the initial radius of bubbles. The numerical results give the information for the effect of Non-Newtonian characteristics to the lateral movement of bubbles due to the mutual interactions. The quantitative detail analysis will be given in the talk.