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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, a numerical study of MHD natural convection in an upright porous cylindrical annulus filled with magnetized nanomaterial is made by using the specificity of nanoliquids to improve the phenomenon of heat transport.

111 citations

Journal ArticleDOI
TL;DR: In this article, the authors consider a magnetohydrodynamic (MHD) third grade fluid confined in a circular cylindrical tube and derive the stream function, axial velocity and pressure gradient analytically for small Deborah number.
Abstract: We consider incompressible, magnetohydrodynamic (MHD) third grade fluid confined in a circular cylindrical tube. The tube surfaces are electrically non-conducting. Travelling sinusoidal wave is imposed on the tube which induces peristaltic motion in the fluid. The stream function, axial velocity and pressure gradient are determined analytically for small Deborah number ( Γ ) . The analysis consists of a perturbation expansion in terms of the Deborah number up to O ( Γ ) . Solutions for pressure rise and frictional force per wavelength are given through the use of numerical integration. The general solution of highly non-linear equation for the hydrodynamic third grade fluid is developed. The results are finally compared with the third grade hydrodynamic and Newtonian fluid cases. It is found that the axial velocity increases by increasing Deborah number but decreases for large values of Hartmann number.

111 citations

Journal ArticleDOI
TL;DR: In this paper, the authors used the finite difference method to predict the characteristics of hydromagnetic double-diffusive convective flow of a binary gas mixture in a rectangular enclosure with the upper and lower walls being insulated.

110 citations

Journal ArticleDOI
TL;DR: In this article, the closed-form solutions of peristaltic flow of Jeffery fluid under the simultaneous effects of magnetohydrodynamics (MHD) and partial slip conditions in a rectangular duct are studied.

110 citations

Journal ArticleDOI
TL;DR: A review of the field of MHD can be found in this article, where Hartmann and Lazarus (1937) and Murgatroyd (1953) provide a comprehensive overview of the literature in the field.
Abstract: Of all areas of MHD, steady, incompressible, rectilinear flow under transverse magnetic fields has probably received most attention and is now well understood. A review of the field would therefore appear to be timely. This review also briefly refers to three-dimensional, nonrectilinear flows but concentrates throughout on cases where the Hartmann number M or Bg(a/~I)112 is large./3, g, a, and ~ are imposed magnetic field, representative length scale, electrical conductivity and viscosity, respectively. The name celebrates Hartmann (1937) and Hartmann & Lazarus (1937), who did first serious theoretical and experimental work on liquid metal MHD flows. These flows have rightly received much attention from theoreticians because the equations are linear but the phenomena are neither trivially simple nor physically unattainable in the laboratory. Even the generalized threedimensional flows prove to be remarkably tractable when M is large. But we are of the opinion that the time has now come for a moratorium on theoretical papers that consist of trivial variations on well-understood problems in the field, unrelated to practical needs. In view of the very large number of relevant theoretical papers, we refer only to the more significant ones that pertain to the case of large M. Note that greater practical interest attaches to laminar flow theory than is usual in fluid mechanics because turbulence tends to be suppressed by a magnetic field, as Hartmann & Lazarus (1937) and Murgatroyd (1953) observed. But note also that a magnetic field can sometimes so deform a velocity pattern that nonlaminar motion may be promoted, as Lehnert (1951 and 1955) remarked. Because of the difficulties, papers by experimentalists are much rarer, and these we refer to comprehensively, particularly where theoretical predictions are being tested. It is worth noting that not all experiments are equally formidable, and electrically driven ones are easily mounted. There is still a great need for experiments in which internal measurements of velocity, etc., are made. As the essence of these flows is the interaction between solid surfaces and the fluid, they find application less in the natural phenomena of astro- or geophysics than in technology. Some problems are significant in relation to liquid metal devices such as electromagnetic pumps, flowmeters, MHD gen

109 citations


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