Observation of a Free-Shercliff-Layer Instability in Cylindrical Geometry

Abstract

We report on observations of a free-Shercliff-layer instability in a Taylor-Couette experiment using a liquid metal over a wide range of Reynolds numbers, $Re\sim 10^3-10^6$. The free Shercliff layer is formed by imposing a sufficiently strong axial magnetic field across a pair of differentially rotating axial endcap rings. This layer is destabilized by a hydrodynamic Kelvin-Helmholtz-type instability, characterized by velocity fluctuations in the $r-\theta$ plane. The instability appears with an Elsasser number above unity, and saturates with an azimuthal mode number $m$ which increases with the Elsasser number. Measurements of the structure agree well with 2D global linear mode analyses and 3D global nonlinear simulations. These observations have implications for a range of rotating MHD systems in which similar shear layers may be produced.

5 pages, 4 figures

References in corpus (4)

• Hydrodynamic turbulence cannot transport angular momentum effectively in astrophysical disks
• Experimental observation and characterization of the magnetorotational instability
• Experiments on the magnetorotational instability in helical magnetic fields
• Magnetized Ekman Layer and Stewartson Layer in a Magnetized Taylor-Couette Flow

Cited by in corpus (5)

• Numerical simulations of the Princeton magneto-rotational instability experiment with conducting axial boundaries
• Quasi-two-dimensional nonlinear evolution of helical magnetorotational instability in a magnetized Taylor-Couette flow
• Magnetic field dynamos and magnetically triggered flow instabilities
• Transition to turbulence in ferrofluids
• Laboratory experiments and numerical simulations on magnetic instabilities