Self-sustaining oscillations of a falling sphere through Johnson-Segalman fluids

2012/09/06 by Young-Ju Lee, Lee, Young-Ju, Chen-Song Zhang +1
Chemical Engineering · Medicine · Engineering · #Rheology and Fluid Dynamics Studies #Blood properties and coagulation #Fluid Dynamics and Turbulent Flows

paper · pdf · doi:10.48550/arxiv.1209.1328

Abstract

We confirm numerically that the Johnson-Segalman model is able to reproduce the continual oscillations of the falling sphere observed in some viscoelastic models. The empirical choice of parameters used in the Johnson-Segalman model is from the ones that show the non-monotone stress-strain relation of the steady shear flows of the model. The carefully chosen parameters yield continual, self-sustaining, (ir)regular and periodic oscillations of the speed for the falling sphere through the Johnson-Segalman fluids. In particular, our simulations reproduce the phenomena: the falling sphere settles slower and slower until a certain point at which the sphere suddenly accelerates and this pattern is repeated continually.

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