### Abstract

Shear layers in confined liquid metal magnetohydrodynamic (MHD) flow play an important role in geo- and astrophysical bodies as well as in engineering applications. We present an experimental and numerical study of liquid metal MHD flow in a modified cylindrical annulus that is driven by an azimuthal Lorentz force resulting from a forced electric current under an imposed axial magnetic field. Hartmann and Reynolds numbers reach M_{max} ≈ 2000 and Re_{max} ≈ 1.3 × 10^{4}, respectively, in the steady regime. The peculiarity of our model geometry is the protruding inner disk electrode which gives rise to a free Shercliff layer at its edge. The flow of liquid GaInSn in the experimental device ZUCCHINI (ZUrich Cylindrical CHannel INstability Investigation) is probed with ultrasound Doppler velocimetry. We establish the base flow in ZUCCHINI and study the scaling of velocities and the free Shercliff layer in both experiment and finite element simulations. Experiment and numerics agree well on the mean azimuthal velocity u_{ϕ}(r) following the prediction of a large-M theoretical model. The large-M limit, which is equivalent to neglecting inertial effects, appears to be reached for M ≳ 30 in our study. In the numerics, we recover the theoretical scaling of the free Shercliff layer δ_{S} ~ M^{-1/2} whereas δ_{S} appears to be largely independent of M in the experiment.

Original language | English |
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Article number | 077101 |

Journal | Physics of Fluids |

Volume | 27 |

Issue number | 7 |

DOIs | |

Publication status | Published - 2015 |

Externally published | Yes |

### Keywords

- Electrodes
- Magnetic Fields
- Electric Currents
- Megnetohydrodynamics
- Flow

### ASJC Scopus subject areas

- Condensed Matter Physics

## Fingerprint Dive into the research topics of 'Experimental and Numerical Study of Electrically Driven Magnetohydrodynamic Flow in a Modified Cylindrical Annulus. I. Base flow'. Together they form a unique fingerprint.

## Cite this

*Physics of Fluids*,

*27*(7), [077101]. https://doi.org/10.1063/1.4923746