Laminar-Turbulent Transition in Magnetohydrodynamic Duct, Pipe, and Channel Flows

2014 ◽  
Vol 66 (3) ◽  
Author(s):  
Oleg Zikanov ◽  
Dmitry Krasnov ◽  
Thomas Boeck ◽  
Andre Thess ◽  
Maurice Rossi
Keyword(s):  
Magnetic Field ◽  
Flow Behavior ◽  
Homogeneous Magnetic Field ◽  
Channel Flows ◽  
Conducting Fluid ◽  
Computational Results ◽  
Electrically Conducting ◽  
Turbulent Transition ◽  
Electrically Conducting Fluid ◽  
Laminar Turbulent Transition

A magnetic field imposed on a flow of an electrically conducting fluid can profoundly change flow behavior. We consider this effect for the situation of laminar-turbulent transition in magnetohydrodynamic duct, pipe, and channel flows with homogeneous magnetic field and electrically insulating walls. Experimental and recent computational results obtained for flows in pipes, ducts and channels are reviewed.

Convection of Electrically Conducting Fluid in a Rotating Magnetic System: Cross rolls

2020 ◽  
Author(s):  
Yadagiri Rameshwar ◽  
Gudukuntla Srinivas ◽  
Hari Ponnamma Rani ◽  
Jozef Brestensky ◽  
Enrico Filippi
Keyword(s):  
Magnetic Field ◽  
Flow Behavior ◽  
Linear Equations ◽  
Finite Amplitude ◽  
Conducting Fluid ◽  
Energy Potential ◽  
Onset Of Convection ◽  
Horizontal Magnetic Field ◽  
Electrically Conducting ◽  
Electrically Conducting Fluid

<p>We have studied theoretically the weakly nonlinear analysis in a rotating Rayleigh-Benard system of electrically conducting fluid in the presence of applied horizontal magnetic field with free-free boundary conditions [1]. This theoretical approach is carried near the onset of convection to study the flow behavior at the occurrence of cross rolls, which are perpendicular to the applied magnetic field. The nonlinear problem is solved by using the Fourier analysis of perturbations up to the O(ε<sup>8</sup>) to study the cross rolls visualization [2,3]. The dependence of the Nusselt number on the Rayleigh number, Ekman number, Elsasser number is extensively examined. The fluid flow is visualized in terms of kinetic energy, potential energy, streamlines, isotherms, and heatlines.</p><p> </p><p>References :</p><p>[1] P. H. Roberts and C. A. Jones , The Onset of Magnetoconvection at Large Prandtl Number in a Rotating Layer I. Finite Magnetic Diffusion, Geophysical and Astrophysical Fluid Dynamics, Vol. 92, pp. 289-325 (2000).</p><p>[2] H.L. Kuo, Solution of the non-linear equations of the cellular convection and heat transport,  Journal of Fluid Mechanics,  Vol.10, pp.611-630 (1961).</p><p>[3] Y. Rameshwar, M. A. Rawoof Sayeed, H. P. Rani, D. Laroze, Finite amplitude cellular convection under the influence of a vertical magnetic field, International Journal of Heat and Mass Transfer, Vol. 114, pp.  559-577 (2017).</p>

scholarly journals The Rayleigh Problem for a Third Grade Electrically Conducting Fluid in a Magnetic Field

2008 ◽  
Vol 15 (sup1) ◽  
pp. 77-90 ◽  
Author(s):  
Tasawar Hayat ◽  
Herman Mambili-Mamboundou ◽  
Ebrahim Momoniat ◽  
Fazal M Mahomed
Keyword(s):  
Magnetic Field ◽  
Conducting Fluid ◽  
Third Grade ◽  
Electrically Conducting ◽  
Electrically Conducting Fluid ◽  
Rayleigh Problem

Effect of a magnetic field and Coriolis forces on Rayleigh–Taylor's instability

1969 ◽  
Vol 47 (15) ◽  
pp. 1621-1635 ◽  
Author(s):  
J. M. Gandhi
Keyword(s):  
Magnetic Field ◽  
Variational Principles ◽  
Vertical Axis ◽  
Finite Depth ◽  
Conducting Fluid ◽  
Wave Number ◽  
Constant Growth Rate ◽  
Horizontal Magnetic Field ◽  
Electrically Conducting ◽  
Electrically Conducting Fluid

We present variational principles which characterize the solution of the equilibrium of a plane horizontal layer of an incompressible, electrically conducting fluid of electrical conductivity σ e.m.u., of magnetic permeability K, having a variable density ρ(z) in the vertical z direction, which is also the direction of gravity having acceleration g, and of viscosity μ(z) and which is rotating at Ω radians per second about the vertical axis in the presence of a horizontal magnetic field for the two cases:(i) When the electrically conducting fluid is assumed to be nonrotating (Ω = 0), with the conductivity σ being finite and the horizontal magnetic field being uniform.(ii) When the electrically conducting fluid is assumed to be rotating (Ω ± 0), with the conductivity σ being infinite and the horizontal magnetic field being stratified.Based on the variational principles for these two cases, an approximate solution is obtained for the special case of a fluid of finite depth d stratified according to the law ρ0 = ρ1 exp βz (ρ1 and β are some constants), for which kinematic viscosity ν is assumed to be constant. Growth rate and total wave number of the disturbance are related by two cubic equations, and for simplified cases explicit solutions are obtained. The properties of hydromagnetic waves generated are discussed.

Mechanisms for magnetic field reversals

2010 ◽  
Vol 368 (1916) ◽  
pp. 1595-1605 ◽  
Author(s):  
F. Pétrélis ◽  
S. Fauve
Keyword(s):  
Magnetic Field ◽  
Turbulent Flow ◽  
Numerical Simulations ◽  
Large Scale ◽  
Conducting Fluid ◽  
Similar Model ◽  
Electrically Conducting ◽  
Electrically Conducting Fluid ◽  
Simple Mechanism ◽  
The Magnetic Field

We present a review of the different models that have been proposed to explain reversals of the magnetic field generated by a turbulent flow of an electrically conducting fluid (fluid dynamos). We then describe a simple mechanism that explains several features observed in palaeomagnetic records of the Earth’s magnetic field, in numerical simulations and in a recent dynamo experiment. A similar model can also be used to understand reversals of large-scale flows that often develop on a turbulent background.

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