Roll Formation in Shampoo Vibrated on a Plate

admin — Fri, 22 May 2009 00:06:21 +0000

Shampoo, a shear thinning fluid, is vibrated at several frequencies. Above a critical oscillation amplitude, rolls form. The fluid flow is similar to two adjacent Rayleigh-Bernard convection cells with the left one rotating CW and the right one CCW. This video documents the behavior and formation of these rolls.

Note: Apparently youtube doesn’t let you upload copyrighted music…ignore the bit at the end.

Duration : 0:4:43

Technorati Tags: Complex Fluids, Complexity, fluid dynamics, Fluids, Non-Newtonian, Patten Formation, shampoo, Shear-Thinning

Shampoo vibrated on a plate

admin — Mon, 04 May 2009 18:27:09 +0000

A layer of shampoo is vibrated in a petri dish at 60Hz. Depending on the oscillation amplitude, several phenomena are observed. Most interesting, is the formation of a stable rolling column, documented in this video. Column is made from two adjacent rolls, with fluid flowing down the center of the column and up at the edges. Circular flow cells can be formed if the column is not in contact with the dish’s walls.

I built this apparatus to investigate the vibration of shear-thickening particulate suspensions (high-mass fraction cornstarch solutions) but decided to try out shampoo because it was a shear thinning fluid. I think the explanation lies in the shampoo’s high-viscosity and shear-thinning property. I just observed this for the first time minutes ago, and haven’t come up with any explanation yet. Also, the shampoo gets opaque after vibration – I think it may even be forming a very soft foam.

Duration : 0:1:58

Technorati Tags: fluid dynamics, non-linear, oscillator, physics, science, shampoo, shear-thinning fluid

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Roll Formation in Shampoo Vibrated on a Plate

Shampoo vibrated on a plate