Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
4995518 | Journal of Non-Newtonian Fluid Mechanics | 2017 | 8 Pages |
Abstract
This work investigates the dynamics of a single bubble rising in a polymer solution confined in a vertical Hele-Shaw cell. Different mixtures of PEO (polyethylene oxide) in water have been used, which exhibit a Newtonian viscosity plateau, followed by a shear-thinning behavior above a shear rate of 0.1 to 1, typically. Depending on the bubble volume, different regimes are reported. When increasing the bubble volume, a transition is observed from a small, round bubble to a cusped bubble, which exhibits a singularity at the rear. Below a critical volume, the bubble rises vertically and does not exhibit any apparent shape deformation. However, above a critical volume, the cusped bubble develops a peculiar instability. Its front flattens at a given angle respect to the horizontal, leading to either a deflection in its trajectory, or its fragmentation. We characterize these two dynamics and interpret the fragmentation process in terms of a viscous fingering recalling the Saffman-Taylor instability. Interestingly, the finger growth is directly controlled by the bubble size.
Related Topics
Physical Sciences and Engineering
Chemical Engineering
Fluid Flow and Transfer Processes
Authors
Raphaël Poryles, Valérie Vidal,