Experimental observation of shear thickening oscillation


We report experimental observation of the shear thickening oscillation, which is a spontaneous macroscopic oscillation in the shear flow of severe shear thickening fluid[1]. The shear thickening oscillation is caused by the interplay between the fluid dynamics and the shear thickening, and has been predicted theoretically by the present authors using a phenomenological fluid dynamics model for the dilatant fluid, but never been reported experimentally.
Using a density-matched starch-water mixture, in the cylindrical shear flow of a few centimeters flow width, we observed strong vibrations of the frequency around 20 Hz, which is consistent with our theoretical prediction. Two dimensional simulation of the cylindrical flow shows that a localized thickened band appears when the external stress exceeds a certain value, and the band governs the shear thickening oscillation.

[1] S. Nagahiro, H. Nakanishi and N. Mitarai, arXiv:1221.2886

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