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Hartmann number

About: Hartmann number is a research topic. Over the lifetime, 2593 publications have been published within this topic receiving 61342 citations.


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TL;DR: In this paper, the effects of a magnetic field on mixed convection flow in a two-sided lid-driven cavity have been analyzed by the lattice Boltzmann method (LBM).
Abstract: In this paper the effects of a magnetic field on mixed convection flow in a two-sided lid-driven cavity have been analyzed by the lattice Boltzmann method (LBM). The Hartmann number varied from Ha = 0 to 100. The study has been conducted for different Richardson numbers (Ri) from 0.01 to 100 while the direction of the magnetic field was investigated in the x-direction. Consequences demonstrate that the heat transfer augments with an increment of the Richardson number for different Hartmann numbers for two cases. The heat transfer declines with the growth of the magnetic field for various Richardson numbers for two cases. The difference between the values of heat transfer for the two cases at variant parameters is negligible but the trend of fluid flow for the two cases is multifarious. © 2011 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library (wileyonlinelibrary.com/journal/htj). DOI 10.1002/htj.20402

21 citations

Journal ArticleDOI
TL;DR: It is shown that the end plates introduce, besides the well-known Ekman circulation, similar magnetic effects which arise for infinite, rotating plates, horizontally unbounded by any walls, and that the currents induced by the plates can give rise to instability for the considered parameters.
Abstract: We study magnetic effects induced by rigidly rotating plates enclosing a cylindrical magnetohydrodynamic (MHD) Taylor-Couette flow at the finite aspect ratio $H∕D=10$. The fluid confined between the cylinders is assumed to be liquid metal characterized by small magnetic Prandtl number, the cylinders are perfectly conducting, an axial magnetic field is imposed with Hartmann number $\text{Ha}\ensuremath{\approx}10$, and the rotation rates correspond to Reynolds numbers of order ${10}^{2}--{10}^{3}$. We show that the end plates introduce, besides the well-known Ekman circulation, similar magnetic effects which arise for infinite, rotating plates, horizontally unbounded by any walls. In particular, there exists the Hartmann current, which penetrates the fluid, turns in the radial direction, and together with the applied magnetic field gives rise to a force. Consequently, the flow can be compared with a Taylor-Dean flow driven by an azimuthal pressure gradient. We analyze the stability of such flows and show that the currents induced by the plates can give rise to instability for the considered parameters. When designing a MHD Taylor-Couette experiment, special care must be taken concerning the vertical magnetic boundaries so that they do not significantly alter the rotational profile.

21 citations

Journal ArticleDOI
TL;DR: In this paper , the authors used the SIMPLE algorithm and the volume control technique to investigate the natural convection of alumina/H2O nanofluids (NFs) flow in a cavity.
Abstract: The SIMPLE algorithm and the volume control technique are used to investigate the natural convection of alumina/H2O nanofluids (NFs) flow in a cavity. The cavity consists of two hot triangular blades on the bottom wall. The two sidewalls are insulated and the upper wall is at a low-temperature. The cavity can have different angles. Brownian nanoparticle motion is also considered to model their thermal conductivity and viscosity. Finally, the values ​​of Nusselt number (Nu), Bejan number (Be) entropy generation rate (Sgen) are estimated by changing the cavity angle (γ), the Hartmann number (Ha), and the Rayleigh number (Ra). It is found that an increment in the Ra enhances the amount of Nu and Sgen, but the amount of Be is reduced. An enhancement in the Ha does not effect on Sgen and Nu at low values of Ra, while for high amounts of Ra, Sgen and Nu are reduced. The maximum value of Sgen and Nu and the minimum amount of Be, which are 10.36, 5.21, and 0.34, respectively, occur when γ = 30°. Also, the minim values of Nu and Sgen occur for strong free convection in the horizontal and vertical cavity, respectively.

21 citations

Journal ArticleDOI
TL;DR: In this paper, the entropy of hybrid nanofluids flow driven by cilia beating is examined theoretically in a hyperbolic tangent fluid model and the impacts of the Arrhenius activation energy input and Ohmic heating on the flow analysis are also explored.

21 citations

Journal ArticleDOI
TL;DR: Conducting fluids flow instabilities characterized by incipience at critical electric Hartmann number and convection rate proportional to electric Reynolds number are characterized in this paper, where the authors show that the flow instability is characterized by the incipientity of conducting fluids.
Abstract: Conducting fluids flow instabilities characterized by incipience at critical electric Hartmann number and convection rate proportional to electric Reynolds number

21 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023122
2022234
2021236
2020219
2019231
2018176