Hostname: page-component-586b7cd67f-2plfb Total loading time: 0 Render date: 2024-11-20T08:29:09.757Z Has data issue: false hasContentIssue false
  • English
  • Français

Experimental observation of swirl accumulation in a magnetically driven flow

Published online by Cambridge University Press:  10 December 2008

I. GRANTS ,
C. ZHANG ,
S. ECKERT  and
G. GERBETH
I. GRANTS
Affiliation:
Forschungszentrum Dresden–Rossendorf, PO Box 510119, 01314 Dresden, [email protected]
C. ZHANG
Affiliation:
Forschungszentrum Dresden–Rossendorf, PO Box 510119, 01314 Dresden, [email protected]
S. ECKERT
Affiliation:
Forschungszentrum Dresden–Rossendorf, PO Box 510119, 01314 Dresden, [email protected]
G. GERBETH
Affiliation:
Forschungszentrum Dresden–Rossendorf, PO Box 510119, 01314 Dresden, [email protected]
Get access Rights & Permissions [Opens in a new window]

Abstract

Independent poloidal and azimuthal body forces are induced in a liquid metal cylinder by travelling and rotating magnetic fields of different frequencies, respectively. The bulk axial and azimuthal velocities are measured by the ultrasound Doppler method. Particle image velocimetry is used to observe the upper free surface velocity distribution. The transition from the poloidal to the azimuthal body force governed regime occurs at a fixed ratio of the respective force magnitude of around 100. This transition is marked by the formation of a concentrated vortex revealing several similarities to intense atmospheric vortices. The vortex structure is controlled by a relatively weak azimuthal force while the maximum speed of the swirl is mainly governed by the poloidal one. Under a certain force ratio the average axial velocity changes its direction in the vortex core, resembling the subsidence in an eye of a tropical cyclone or a large tornado. Multiple moving vortices encircle the vortex core in this regime.

Type
Papers
Information
Journal of Fluid Mechanics , Volume 616 , 10 December 2008 , pp. 135 - 152
Copyright
Copyright © Cambridge University Press 2008

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Andersen, A., Bohr, T., Stenum, B., Juul Rasmussen, J. & Lautrup, B. 2006 The bathtub vortex in a rotating container. J. Fluid Mech. 556, 121–146.CrossRefGoogle Scholar
Bojarevičs, V., Freibergs, J., Shilova, E. I. & Scherbinin, E. V. 1989 Electrically Induced Vortical Flows. Kluwer.CrossRefGoogle Scholar
Bojarevičs, V. & Scherbinin, E. V. 1983 Azimuthal rotation in the axisymmetric meridional flow due to an electric-current source. J. Fluid Mech. 126, 413–430.CrossRefGoogle Scholar
Brown, G. L. & Lopez, J. M. 1990 Axisymmetric vortex breakdown Part 2. Physical mechanisms. J. Fluid Mech. 221, 553–576.CrossRefGoogle Scholar
Church, C. R., Snow, J. T., Baker, G. L. & Agee, E. M. 1979 Characteristics of tornado-like vortices as a function of swirl ratio: a laboratory investigation. J. Atmos. Sci. 36, 1755–1776.2.0.CO;2>CrossRefGoogle Scholar
Cramer, A., Pal, J. & Gerbeth, G. 2007 Experimental investigation of a flow driven by a combination of a rotating and a traveling magnetic field. Phys. Fluids 19, 118109.CrossRefGoogle Scholar
Cramer, A., Zhang, C. & Eckert, S. 2004 Local structures in liquid metals measured by ultrasonic Doppler velocimetry. Flow Meas. Instrum. 15, 145–153.CrossRefGoogle Scholar
Croxford, M. & Barnes, G. M. 2002 Inner core strength of Atlantic tropical cyclones. Mont. Weather Rev. 130, 127–139.2.0.CO;2>CrossRefGoogle Scholar
Davidson, P. A. 1992 Swirling flow in an axisymmetric cavity of arbitrary profile, driven by a rotating magnetic field. J. Fluid Mech. 245, 669–699.CrossRefGoogle Scholar
Davidson, P. A. 2001 An Introduction to Magnetohydrodynamics. Cambridge University Press.CrossRefGoogle Scholar
Davidson, P. A., Kinnear, D., Lingwood, R. J., Short, D. J. & He, X. 1999 The role of Ekman pumping and the dominance of swirl in confined flows driven by Lorentz forces. Eur. J. Mech. B/Fluids 18, 693–711.CrossRefGoogle Scholar
Emanuel, K. A. 1991 The theory of hurricanes. Annu. Rev. Fluid Mech. 23, 179–196.CrossRefGoogle Scholar
Emanuel, K. A. 2003 Tropical cyclones. Annu. Rev. Earth Planet. Sci. 31, 75–104.CrossRefGoogle Scholar
Gelfgat, A. Yu., Bar-Yoseph, P. Z. & Solan, A. 1996 Stability of confined swirling flow with or without vortex breakdown. J. Fluid Mech. 311, 1–36.CrossRefGoogle Scholar
Gelfgat, Yu., KrŪmiņš, J. & Abricka, M. 1999 Motion of an electrically conducting fluid in a cylindrical volume exposed to the influence of superimposed rotating and travelling magnetic fields. Magnitnaya Gidrodinamika 36, 3–16 (in Russian).Google Scholar
Gelfgat, Yu., Skopis, M. & Grabis, J. 2005 Electromagnetically driven vortex flow to introduce small solid particles into liquid metal. Magnetohydrodynamics 41, 249–254.Google Scholar
Gorbachev, L. P., Nikitin, N. V. & Ustinov, A. L. 1974 Magnetohydrodynamic rotation of an electrically conductive liquid in a cylindrical vessel of finite dimensions. Magnitnaya Gidrodinamika 10, 406–414 (in Russian).Google Scholar
Grants, I. & Gerbeth, G. 2004 Stability of melt flow due to a traveling magnetic field in a closed ampoule. J. Cryst. Growth 269, 630–638.CrossRefGoogle Scholar
Klemp, J. B. 1987 Dynamics of tornadic thunderstorms. Annu. Rev. Fluid Mech. 19, 369–402.CrossRefGoogle Scholar
Lantzsch, R., Galindo, V., Grants, I., Zhang, C., Pätzold, O., Gerbeth, G. & Stelter, M. 2007 Experimental and numerical results on the fluid flow driven by a traveling magnetic field. J. Cryst. Growth 305, 249–256.CrossRefGoogle Scholar
Lugt, H. J. 1989 Vortex breakdown in atmospheric columnar vortices. Bull. Am. Met. Soc. 70, 1526–1537.2.0.CO;2>CrossRefGoogle Scholar
Maxworthy, T. 1973 A vorticity source for large-scale dust devils and other comments on naturally occuring columnar vortices. J. Atmos. Sci. 30, 1717–1722.2.0.CO;2>CrossRefGoogle Scholar
Montgomery, M. T., Vladimirov, V. A & Denissenko, P. V. 2002 An experimental study on hurricane mesovortices. J. Fluid Mech. 471, 1–32.CrossRefGoogle Scholar
Nolan, D. S. & Farrell, B. F. 1999 The structure and dynamics of tornado-like vortices. J. Atmos. Sci. 56, 2908–2936.2.0.CO;2>CrossRefGoogle Scholar
Shapiro, A. H. 1962 Bath-tub vortex. Nature 196, 1080–1081.CrossRefGoogle Scholar
Sozou, C. & Pickering, W. M. 1976 Magnetohydrodynamic flow due to the discharge of an electric current in a hemispherical container. J. Fluid Mech. 73, 641–650.CrossRefGoogle Scholar
Stiller, J., Koal, K., Fraňa, K. & Grundmann, R. 2006 Stirring of melts using rotating and travelling magnetic fields. InProc. 5th Intl Conf. on CFD in the Process Industries, Melbourne, Australia (ed. Witt, P. J. & Schwarz, M. P.). CSIRO, Collingwood.Google Scholar
Takeda, Y. 1991 Development of an ultrasound velocity profile monitor. Nucl. Engng Des. 126, 277–284.CrossRefGoogle Scholar
Ward, N. B. 1972 The exploration of certain features of tornado dynamics using a laboratory model. J. Atmos. Sci. 29, 1194–1204.2.0.CO;2>CrossRefGoogle Scholar
Willoughby, H. E. 1990 Temporal changes of the primary circulation in tropical cyclones. J. Atmos. Sci. 47, 242–264.2.0.CO;2>CrossRefGoogle Scholar