Oscillations of a solid sphere falling through a wormlike micellar fluid

Anandhan Jayaraman; Andrew Belmonte

doi:10.1103/physreve.67.065301

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Oscillations of a solid sphere falling through a wormlike micellar fluid

Anandhan Jayaraman·Andrew Belmonte

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Abstract

We present an experimental study of the motion of a solid sphere falling through a wormlike micellar fluid. While smaller or lighter spheres quickly reach a terminal velocity, larger or heavier spheres are found to oscillate in the direction of their falling motion. The onset of this instability correlates with a critical value of the velocity gradient scale $Γ_{c}\sim 1$ s$^{-1}$. We relate this condition to the known complex rheology of wormlike micellar fluids, and suggest that the unsteady motion of the sphere is caused by the formation and breaking of flow-induced structures.

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Anandhan Jayaraman, Andrew Belmonte. 2002-05-24. Oscillations of a solid sphere falling through a wormlike micellar fluid. https://doi.org/10.1103/physreve.67.065301

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