ABSTRACT The present work aims at understanding the behaviors of bubbles in non-Newtonian fluids. Several experimental approaches: bubble rise velocity, rheological simulation and birefringence visualization reveal for the first time that in-line interactions are governed by a dynamical competition between the creation and relaxation of stresses in fluids. The chaos analysis applied to time series data of bubble passage at different heights in the bubble column corroborates the deterministic mechanism of the coalescence between bubbles. A cognitive model based on behavioral rules has been developed to describe collective behaviors of a group of bubbles. A theoretical model was developed for describing the non-spherical bubble formation at an orifice. Owing to the knowledge of the interactions, the present model is able to calculate the instantaneous shape of the bubble during its formation and determine the final size of detachment as well as the frequency of bubble formation. Finally, the lattice Boltzmann method was investigated to compute the flow field and stress distribution around a single bubble as well as the bubble’s shape in such complex fluids.
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