Ekman-Hartmann layer in a magnetohydrodynamic Taylor-Couette flow
- Astrophysikalisches Institut Potsdam, An der Sternwarte 16, D-14482 Potsdam (Germany)
We study magnetic effects induced by rigidly rotating plates enclosing a cylindrical magnetohydrodynamic (MHD) Taylor-Couette flow at the finite aspect ratio H/D=10. The fluid confined between the cylinders is assumed to be liquid metal characterized by small magnetic Prandtl number, the cylinders are perfectly conducting, an axial magnetic field is imposed with Hartmann number Ha{approx_equal}10, and the rotation rates correspond to Reynolds numbers of order 10{sup 2}-10{sup 3}. We show that the end plates introduce, besides the well-known Ekman circulation, similar magnetic effects which arise for infinite, rotating plates, horizontally unbounded by any walls. In particular, there exists the Hartmann current, which penetrates the fluid, turns in the radial direction, and together with the applied magnetic field gives rise to a force. Consequently, the flow can be compared with a Taylor-Dean flow driven by an azimuthal pressure gradient. We analyze the stability of such flows and show that the currents induced by the plates can give rise to instability for the considered parameters. When designing a MHD Taylor-Couette experiment, special care must be taken concerning the vertical magnetic boundaries so that they do not significantly alter the rotational profile.
- OSTI ID:
- 21101960
- Journal Information:
- Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics (Print), Vol. 76, Issue 6; Other Information: DOI: 10.1103/PhysRevE.76.066308; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1539-3755
- Country of Publication:
- United States
- Language:
- English
Similar Records
Nonaxisymmetric MHD instabilities of Chandrasekhar states in Taylor-Couette geometry
Diffusive magnetohydrodynamic instabilities beyond the Chandrasekhar theorem