Physics:Kaye effect
The Kaye effect is a property of complex liquids which was first described by the United Kingdom engineer Alan Kaye in 1963.[1]
While pouring one viscous mixture of an organic liquid onto a surface, the surface suddenly spouted an upcoming jet of liquid which merged with the downgoing one.
This phenomenon has since been discovered to be common in many non-Newtonian liquids (liquids with a shear stress dependent viscosity or viscoelastic properties). Common household liquids in this category are liquid hand soaps, shampoos and non-drip paint. The effect usually goes unnoticed, however, because it seldom lasts more than about 300 milliseconds. The effect can be sustained by pouring the liquid onto a slanted surface, preventing the outgoing jet from intersecting the downward one (which tends to end the effect).
Whilst it was long thought to occur due to a shear-thinning slip layer,[2] recent studies have shown through high-speed videos[3] and experiments in a vacuum chamber[4] that an extremely thin layer of air (approximately 1000 times thinner than the jet diameter) is entrained, which acts as a lubricant and supports the sliding jet.
The current theory is that viscoelasticity is key. In a jet viscoelastic fluid, a portion of the energy of deformation as the jet falls is recoverable, and this reduces the force required to support the leaping jet, enabling more air to be entrained.[4]
References
- ↑ Kaye, A. (1963). "A Bouncing Liquid Stream". Nature 197 (4871): 1001–1002. doi:10.1038/1971001a0. Bibcode: 1963Natur.197.1001K.
- ↑ Versluis, M; Blom, C et al. (2006). "Leaping shampoo and the stable Kaye effect". Journal of Statistical Mechanics: Theory and Experiment 2006 (7): P07007. doi:10.1088/1742-5468/2006/07/P07007.
- ↑ Lee, S; Li, E et al. (2013). "Leaping shampoo glides on a lubricating air layer". Physical Review E 87 (6): 061001. doi:10.1103/PhysRevE.87.061001. PMID 23848618. Bibcode: 2013PhRvE..87f1001L.
- ↑ 4.0 4.1 King, J; Lind, S (2019). "The Kaye effect: New experiments and a mechanistic explanation". Journal of Non-Newtonian Fluid Mechanics 273: 104165. doi:10.1016/j.jnnfm.2019.104165.
External links
- Bizarre liquid jets explained - the Kaye effect
- Puzzle of Leaping Liquid Solved.
- The Kaye effect using shampoo.
- The Kaye effect shot through a high speed camera.
 |  |
