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Scientists of the University of Twente in The Netherlands won a prestigious place in the ‘Hall of Fame’ of videos about fluid-in-motion.
They have made a video of leaping shampoo, in which they explain the so-called Kaye effect.
A. Kaye in Nature magazine in 1963 wrote “I can offer no explanation for this behaviour.”
At high-speed recording of 1000 frames per second the following observations were made in 300ms interval:
1) a heap is formed, 2) a streamer ejects, 3) the outgoing jet rises, 4) hits the incoming jet, 5) ends the Kaye effect.
What causes the Kaye effect?
Streamer ejects through shear-thinning property of fluid. A dimple is formed in the viscous heap. Outgoing jet is thicker quantitatively following continuity. The dimple deepens through a vertical force acting on the viscous heap and the jet rises.
The scientists set up a simple energy balance model. It includes viscous dissipation and the sear-thinning behavior of the shampoo in the dimple structure. Elastic properties of the fluid play no role.
The model predicts the leap height of the shampoo as a function of the release height. It even predicts a critical release height as observed in experiment. (For details see: JSTAT / 2006 / P07007)
To prevent the outgoing jet from interfering with the incoming jet the surface was tilted, leading to a stable Kaye effect cascade.
Leaping shampoo may even act as a light guide for laser beams in multitude of colors.
The people who worked on this are: Michel Versluis, Cor Blom, Devaraj van Meer, Ko van der Weele, Detlef Lohse.
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Technorati Tags: balance, dimple, effect, energy, fluid, force, guide, heap, high, in, jet, kaye, laser, light, model, motion, netherlands, of, resolution, shampoo, streamer, twente, University
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.
23/6/08