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with larger field strength during thermomagnetic convection, which displaces warmer fluid of lower susceptibility. They showed that thermomagnetic convection can be correlated with a dimensionless magnetic
Rayleigh number. Heat transfer due to this form of convection can be much more effective than buoyancy-induced convection for systems with small dimensions.
87:
with two terms. The first term can be treated as a magnetostatic pressure. In contrast, the second is important only if there is a spatial gradient of the fluid susceptibility, e.g., in a non-isothermal system. The colder fluid that has a larger magnetic susceptibility is attracted towards regions
62:
Ozoe group has studied thermomagnetic convection both experimentally and numerically. They showed how to enhance, suppress, and invert the convection modes. They have also carried out scaling analysis for paramagnetic fluids in microgravity conditions.
226:
Bednarz, Tomasz P.; Lin, Wenxian; Patterson, John C.; Lei, Chengwang; Armfield, Steven W. (2009). "Scaling for unsteady thermo-magnetic convection boundary layer of paramagnetic fluids of Pr>1 in micro-gravity conditions".
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or momentum equation governing fluid flow as the "Kelvin body force (KBF)". Recently, Kumar et.al shed new light on the 20-plus year-old question of the appropriate tensor form of the Kelvin body force in
Ferrofluids.
198:
Bednarz, Tomasz; Patterson, John C.; Lei, Chengwang; Ozoe, Hiroyuki (2009). "Enhancing natural convection in a cube using a strong magnetic field — Experimental heat transfer rate measurements and flow visualization".
119:) = 0 for constant temperature flow. Such a symmetric field does not alter the velocity. However, if the temperature distribution about the imposed magnetic field is asymmetric, so is the KBF in which case curl(
264:[Kumar, V., Dau, V., Javanbakht, Z., Seager, A., Nguyen, N., and Woodfield, P. (2023). Updated formulation of magnetic body force in ferrofluids. International Journal of Engineering Science, 192, 103929.
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Bednarz, Tomasz; Tagawa, Toshio; Kaneda, Masayuki; Ozoe, Hiroyuki; Szmyd, Janusz S. (2004). "Magnetic and
Gravitational Convection of Air with a Coil Inclined Around the X Axis".
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fails to provide adequate heat transfer, e.g., in miniature microscale devices or under reduced gravity conditions.
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The KBF creates a static pressure field that is symmetric about a magnet, e.g., a line dipole, that produces a
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79::3485-3492, (2005)) also shows that this form of convection can be correlated with a dimensionless magnetic
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103:, the susceptibility is a function of the temperature. This produces a force that can be expressed in the
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51:, e.g., due to a temperature gradient, results in a nonuniform magnetic body force, which leads to
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A comprehensive review of thermomagnetic convection (in A. Mukhopadhyay, R. Ganguly, S. Sen, and
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first explained in 1970 (in his paper "Convective instability of ferromagnetic fluids",
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and on the fluid magnetic susceptibility. In a ferrofluid flow encompassing varying
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47::753-767) how an external magnetic field imposed on a ferrofluid with varying
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55:. This form of heat transfer can be useful for cases where conventional
123:) ≠0. Such an asymmetric body force leads to ferrofluid motion across
83:. Subsequently, this group explained that fluid motion occurs due to a
70:, "Scaling analysis to characterize thermomagnetic convection",
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Phys. Fluids 16, 2228 (2004); doi:10.1063/1.1736691 (9 pages)
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in such magnetic fluids can be controlled using an external
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depends on the local value of the applied magnetic field
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187:http://www.htsj.or.jp/TSE/TSE_14_4/TSE_14_4_7.pdf
73:International Journal of Heat and Mass Transfer
266:https://doi.org/10.1016/j.ijengsci.2023.103929
146:Numerical Heat Transfer, Part A: Applications
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229:International Journal of Heat and Fluid Flow
213:10.1016/j.icheatmasstransfer.2009.06.005
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241:10.1016/j.ijheatfluidflow.2009.08.003
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14:
115:-free force field, i.e., curl(
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40:Journal of Fluid Mechanics
166:10.1080/10407780490457464
53:thermomagnetic convection
49:magnetic susceptibility
295:Continuum mechanics
158:2004NHTA...46...99B
85:Kelvin body force
23:, since heat and
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235:(6): 1157–1170.
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91:The ferrofluid
81:Rayleigh number
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19:can be used to
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207:(8): 781–786.
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25:mass transport
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152:(1): 99–113.
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17:Ferrofluids
285:Convection
279:Categories
131:References
68:I. K. Puri
57:convection
290:Magnetism
174:119902658
125:isotherms
154:Bibcode
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170:S2CID
113:curl
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