Hierarchy of concentration waves in magnetic fluidized beds

• Published in: Journal of magnetism and magnetic materials Vol. 289; pp. 111 - 114
• Main Authors: Sobral, Y.D., Cunha, F.R.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01.03.2005; Elsevier Science
• Subjects: Concentration waves; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Magnetic fluidized beds; Magnetic pressure coefficient; Magnetic properties and materials; Physics; Wave hierarchy; 83.80.G; 47.55.K; 47.20.K; Concentration waves; Magnetic fluidized beds; Wave hierarchy; Magnetic pressure coefficient; External fields; Propagation velocity; Magnetization; Partial differential equations; Magnetic field effects; Hyperbolic equations; Wave interaction; 47.20.K Magnetic fluidized beds; Wave propagation; Fluidized beds; Gravity
• ISSN: 0304-8853
• DOI: 10.1016/j.jmmm.2004.11.033

The stability of a polarized fluidized bed is examined by theory which considers an approach of hierarchic interaction of concentration waves. A linear hyperbolic partial differential equation for particle concentration disturbances is obtained and is recast as the sum of two wave operators of different orders, which represent two kinds of waves propagating with different velocities along the fluidized bed. Stability is achieved when the propagation velocity of the higher order waves is greater than that of the lower order waves. It is verified that magnetic effects arisen from the magnetization of the particles in the presence of an external magnetic field act in the sense of increasing the propagation velocity of the higher order waves. The lower order waves, which are originated from the competition between drag and gravity forces on the particles, are found to be unaffected by the magnetic effects.