### 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 |
---|---|

Article number | 077101 |

Journal | Physics of Fluids |

Volume | 27 |

Issue number | 7 |

DOIs | |

Publication status | Published - 2015 |

Externally published | Yes |

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### Keywords

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

### ASJC Scopus subject areas

- Condensed Matter Physics

### Cite this

*Physics of Fluids*,

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

**Experimental and Numerical Study of Electrically Driven Magnetohydrodynamic Flow in a Modified Cylindrical Annulus. I. Base flow.** / Stelzer, Zacharias; Cébron, David; Miralles, Sophie; Vantieghem, Stijn; Noir, Jérôme; Scarfe, Peter; Jackson, Andrew.

Research output: Contribution to journal › Article

*Physics of Fluids*, vol. 27, no. 7, 077101. https://doi.org/10.1063/1.4923746

}

TY - JOUR

T1 - Experimental and Numerical Study of Electrically Driven Magnetohydrodynamic Flow in a Modified Cylindrical Annulus. I. Base flow

AU - Stelzer, Zacharias

AU - Cébron, David

AU - Miralles, Sophie

AU - Vantieghem, Stijn

AU - Noir, Jérôme

AU - Scarfe, Peter

AU - Jackson, Andrew

PY - 2015

Y1 - 2015

N2 - 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 Mmax ≈ 2000 and Remax ≈ 1.3 × 104, 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 uϕ(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 δS ~ M-1/2 whereas δS appears to be largely independent of M in the experiment.

AB - 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 Mmax ≈ 2000 and Remax ≈ 1.3 × 104, 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 uϕ(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 δS ~ M-1/2 whereas δS appears to be largely independent of M in the experiment.

KW - Electrodes

KW - Magnetic Fields

KW - Electric Currents

KW - Megnetohydrodynamics

KW - Flow

UR - http://www.scopus.com/inward/record.url?scp=84937022273&partnerID=8YFLogxK

U2 - 10.1063/1.4923746

DO - 10.1063/1.4923746

M3 - Article

VL - 27

JO - Physics of Fluid

JF - Physics of Fluid

SN - 1070-6631

IS - 7

M1 - 077101

ER -