Research Repository

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Magnetic levitation stabilized by streaming fluid flows (2018)
Journal Article
Baldwin, K., de Fouchier, J., Atkinson, P., Hill, R., Swift, M., & Fairhurst, D. (2018). Magnetic levitation stabilized by streaming fluid flows. Physical Review Letters, 121(6), (064502). doi:10.1103/PhysRevLett.121.064502. ISSN 0031-9007

We demonstrate that the ubiquitous laboratory magnetic stirrer provides a simple passive method of magnetic levitation, in which the so-called ‘flea’ levitates indefinitely. We study the onset of levitation and quantify the flea’s motion (a combinati... Read More

Shapes and fissility of highly charged and rapidly rotating levitated liquid drops (2017)
Journal Article
Liao, L., & Hill, R. J. (2017). Shapes and fissility of highly charged and rapidly rotating levitated liquid drops. Physical Review Letters, 119, doi:10.1103/PhysRevLett.119.114501. ISSN 0031-9007

We use diamagnetic levitation to investigate the shapes and the stability of free electrically charged and spinning liquid drops of volume ∼1 ml. In addition to binary fission and Taylor cone-jet fission modes observed at low and high charge density,... Read More

Magnetically-induced rotating Rayleigh-Taylor instability (2017)
Journal Article
Scase, M. M., Baldwin, K. A., & Hill, R. J. (2017). Magnetically-induced rotating Rayleigh-Taylor instability. Journal of Visualized Experiments, doi:10.3791/55088. ISSN 1940-087X

Classical techniques for investigating the Rayleigh-Taylor instability include using compressed gasses, rocketry or linear electric motors to reverse the effective direction of gravity, and accelerate the lighter fluid toward the denser fluid. Other... Read More

Rotating Rayleigh-Taylor instability (2017)
Journal Article
Scase, M. M., Baldwin, K. A., & Hill, R. J. (in press). Rotating Rayleigh-Taylor instability. Physical Review Fluids, 2(2), doi:10.1103/PhysRevFluids.2.024801. ISSN 2469-990X

The effect of rotation upon the classical Rayleigh-Taylor instability is considered. We consider a two-layer system with an axis of rotation that is perpendicular to the interface between the layers. In general we find that a wave mode’s growth rate... Read More

Propulsion of a two-sphere swimmer (2015)
Journal Article
Klotsa, D., Baldwin, K. A., Hill, R. J., Bowley, R., & Swift, M. R. (2015). Propulsion of a two-sphere swimmer. Physical Review Letters, 115(24), doi:10.1103/PhysRevLett.115.248102. ISSN 0031-9007

We describe experiments and simulations demonstrating the propulsion of a neutrally-buoyant swimmer that consists of a pair of spheres attached by a spring, immersed in a vibrating fluid. The vibration of the fluid induces relative motion of the sphe... Read More

The inhibition of the Rayleigh-Taylor instability by rotation (2015)
Journal Article
Baldwin, K. A., Scase, M. M., & Hill, R. J. (2015). The inhibition of the Rayleigh-Taylor instability by rotation. Scientific Reports, 5(11706), doi:10.1038/srep11706. ISSN 2045-2322

It is well-established that the Coriolis force that acts on fluid in a rotating system can act to stabilise otherwise unstable flows. Chandrasekhar considered theoretically the effect of the Coriolis force on the Rayleigh-Taylor instability, which oc... Read More

Artificial tektites: an experimental technique for capturing the shapes of spinning drops (2015)
Journal Article
Baldwin, K. A., Butler, S. L., & Hill, R. J. (in press). Artificial tektites: an experimental technique for capturing the shapes of spinning drops. Scientific Reports, 5, doi:10.1038/srep07660. ISSN 2045-2322

Determining the shapes of a rotating liquid droplet bound by surface tension is an archetypal problem in the study of the equilibrium shapes of a spinning and charged droplet, a problem that unites models of the stability of the atomic nucleus with t... Read More

Mechanical vibrations of magnetically levitatedviscoelastic droplets (2014)
Journal Article
Temperton, R. H., Hill, R. J., & Sharp, J. S. (2014). Mechanical vibrations of magnetically levitatedviscoelastic droplets. Soft Matter, 10(29), 5375-5379. doi:10.1039/c4sm00982g

The mechanical vibrations of magnetically levitated droplets were investigated using a simple optical deflection technique. Droplets of water and a water-based solution of poly(acrylamide-co-acrylic acid) were levitated in the bore of a superconducti... Read More