TY - JOUR
T1 - Negative wake and velocity of a bubble rising in a viscoelastic fluid
AU - Pillapakkam, Shriram B.
AU - Singh, Pushpendra
PY - 2003/1/1
Y1 - 2003/1/1
N2 - A three-dimensional finite element based numerical method is used to simulate the rise of a bubble in a viscoelastic fluid modeled by the Oldroyd-B model. The rise velocity is studied as a function of the bubble volume on a log-log plot. The dependence of rise velocity on the bubble shape and the viscoelastic properties of the ambient fluid are also investigated. In simulations, rather than a jump in the rise velocity at a critical volume as observed in experiments, we find that there is a steep, but continuous, change in the rise velocity over a very small range of bubble volumes. Interestingly, this steep increase in the rise velocity is exaggerated when a parameter, which is a measure of the polymer concentration, is increased, while keeping the zero-shear viscosity fixed. The wake is 'negative' in the sense that the direction of fluid velocity behind the bubble for this parameter range is the opposite of that for a Newtonian fluid.
AB - A three-dimensional finite element based numerical method is used to simulate the rise of a bubble in a viscoelastic fluid modeled by the Oldroyd-B model. The rise velocity is studied as a function of the bubble volume on a log-log plot. The dependence of rise velocity on the bubble shape and the viscoelastic properties of the ambient fluid are also investigated. In simulations, rather than a jump in the rise velocity at a critical volume as observed in experiments, we find that there is a steep, but continuous, change in the rise velocity over a very small range of bubble volumes. Interestingly, this steep increase in the rise velocity is exaggerated when a parameter, which is a measure of the polymer concentration, is increased, while keeping the zero-shear viscosity fixed. The wake is 'negative' in the sense that the direction of fluid velocity behind the bubble for this parameter range is the opposite of that for a Newtonian fluid.
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U2 - 10.1115/IMECE2003-41473
DO - 10.1115/IMECE2003-41473
M3 - Article
AN - SCOPUS:1842616164
SN - 0888-8116
VL - 259
SP - 709
EP - 714
JO - American Society of Mechanical Engineers, Fluids Engineering Division (Publication) FED
JF - American Society of Mechanical Engineers, Fluids Engineering Division (Publication) FED
ER -