Journal ArticleDOI
Convective instability of ferromagnetic fluids
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In this paper, the Galerkin method is used to predict convective instability of a ferromagnetic fluid in the presence of a uniform vertical magnetic field, where the magnetization of the fluid is a function of temperature and a temperature gradient is established across the layer.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.read more
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Heat transfer enhancement by magnetic nanofluids—A review
Innocent Nkurikiyimfura,Innocent Nkurikiyimfura,Yanmin Wang,Yanmin Wang,Zhidong Pan,Zhidong Pan +5 more
TL;DR: Magnetic nanofluids (MNFs) constitute a special class of materials that exhibit both magnetic and fluid properties as discussed by the authors, and the interest in the use of MNFs as a heat transfer medium stem from a possibility of controlling its flow and heat transfer process via an external magnetic field.
Journal ArticleDOI
Thermal diodes, regulators, and switches: Physical mechanisms and potential applications
Geoff Wehmeyer,Tomohide Yabuki,Tomohide Yabuki,Christian Monachon,Junqiao Wu,Junqiao Wu,Chris Dames,Chris Dames +7 more
TL;DR: In this paper, the fundamental physical mechanisms of switchable and nonlinear heat transfer have been harnessed to make thermal diodes, switches, and regulators, and various nonlinear and active thermal circuits are presented.
Journal ArticleDOI
Magnetically controlled convection in a paramagnetic fluid
TL;DR: In this paper, the strong magnetic fields available from superconducting magnets can be used to induce magnetic convection in normal paramagnetic fluids, such as solutions of paramagnetic salts or melts of paramagon solids, which can be exploited in heat transfer devices or to control microstructures in crystal growth.
References
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Book
Electrodynamics of continuous media
TL;DR: In this article, the propagation of electromagnetic waves and X-ray diffraction of X rays in crystals are discussed. But they do not consider the effects of superconductivity on superconducting conductors.
Journal ArticleDOI
Surface tension and buoyancy effects in cellular convection
TL;DR: In this article, a Fourier series method has been used to obtain the eigenvalue equation for the case where the lower boundary surface is a rigid conductor and the upper free surface is subject to a general thermal condition.
Journal ArticleDOI
The interfacial stability of a ferromagnetic fluid
M. D. Cowley,R. E. Rosensweig +1 more
TL;DR: Magnetization critical level derived for instability onset for ferromagnetic fluid having nonlinear relation with magnetic induction for magnetic induction was derived in this paper, where the critical level is defined as the ratio of instability onset to magnetic induction.