Hostname: page-component-cd9895bd7-gvvz8 Total loading time: 0 Render date: 2024-12-28T04:46:01.924Z Has data issue: false hasContentIssue false

Convective instability of ferromagnetic fluids

Published online by Cambridge University Press:  29 March 2006

B. A. Finlayson
Affiliation:
Department of Chemical Engineering, University of Washington

Abstract

Convective instability of a ferromagnetic fluid is predicted for a fluid layer heated from below in the presence of a uniform vertical magnetic field. Convection is caused by a spatial variation in magnetization which is induced when the magnetization of the fluid is a function of temperature and a temperature gradient is established across the layer. A linearized convective instability analysis predicts the critical temperature gradient when only the magnetic mechanism is important, as well as when both the magnetic and buoyancy mechanisms are operative. The magnetic mechanism predominates over the buoyancy mechanism in fluid layers about 1 mm thick. For a fluid layer contained between two free boundaries which are constrained flat, the exact solution is derived for some parameter values and oscillatory instability cannot occur. For rigid boundaries, approximate solutions for stationary instability are derived by the Galerkin method for a wide range of parameter values. It is shown that in this case the Galerkin method yields an eigenvalue which is stationary to small changes in the trial functions, because the Galerkin method is equivalent to an adjoint variational principle.

Type
Research Article
Copyright
© 1970 Cambridge University Press

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

Bean, C. P. 1955 J. appl. Phys. 26, 1381.
Bolotin, V. V. 1963 Nonconservative Problems of the Theory of Elastic Stability. New York: Macmillan.
Chandrasekhar, S. 1961 Hydrodynamic and Hydromagnetic Stability. Oxford: Clarendon.
Copley, M. D. & Rosensweig, R. E. 1967 J. Fluid Mech. 30, 671.
DiPrima, R. C. & Pan, C. H. T. 1964 Z. angew. Math. Phys. 15, 560.
Finlayson, B. A. 1968 J. Fluid Mech. 33, 201.
Finlayson, B. A. & Scriven, L. E. 1969 Proc. Roy. Soc. Lond. A 310, 183.
Krueger, E. R. & DiPrima, R. C. 1964 J. Fluid Mech. 19, 528.
Kurzweg, U. H. 1964 Z. angew. Math. Phys. 15, 39.
Landau, C. P. & Lifshitz, E. M. 1960 Electrodynamics of Continuous Media. London: Pergamon.
Mikhlin, S. G. 1964 Variational Methods in Mathematical Physics. New York: Macmillan.
Moskowitz, R. & Rosensweig, R. E. 1967 Appl. Phys. Lett. 11, 301.
Neuringer, J. L. & Rosensweig, R. E. 1964 Phys. Fluids, 7, 1927.
Nield, D. A. 1964 J. Fluid Mech. 19, 341.
Papell, S. S. & Faber, O. C. 1966 NASA Tech. Note D-3288.
Papell, S. S. & Faber, O. C. 1968 NASA Tech. Note D-4676.
Penfield, P. & Haus, H. A. 1967 Electrodynamics of Moving Media. Massachusetts Institute of Technology Press.
Poots, G. 1963 J. Fluid Mech. 15, 187.
Besler, E. L. & Rosensweig, R. E. 1964 AIAA J. 2, 1418.
Resler, E. L. & Rosensweig, R. E. 1967 J. Eng. Power, Trans. ASME, A 89, 399.
Ritchie, G. S. 1968 J. Fluid Mech. 32, 131.
Roberts, P. H. 1960 J. Math. anal. Appl. 1, 195.
Rosensweig, R. E. & Kaiser, R. 1967 Study of a Ferromagnetic Liquid. N68–14205.
Turnbull, R. J. 1969 Phys. Fluids, 12, 1809.
Walowit, J. A. 1966 Am. Inst. Chem. Eng. J. 12, 104.
Yeung, K. W. & Yu, C. P. 1968 Bull. Am. Phys. Soc. 11, 1598.