scholarly journals Zero absolute vorticity plane Couette flow as an hydrodynamic representation of quantum energy states under perpendicular magnetic field

2021 ◽  
Vol 33 (12) ◽  
pp. 127120
Author(s):  
E. Heifetz ◽  
L. R. M. Maas ◽  
J. Mak
Keyword(s):  
Magnetic Field ◽  
Couette Flow ◽  
Perpendicular Magnetic Field ◽  
Plane Couette Flow ◽  
Absolute Vorticity ◽  
Quantum Energy ◽  
Energy States

scholarly journals High-speed shear-driven dynamos. Part 2. Numerical analysis

2019 ◽  
Vol 876 ◽  
pp. 830-858 ◽  
Author(s):  
Kengo Deguchi
Keyword(s):  
Magnetic Field ◽  
Reynolds Number ◽  
Couette Flow ◽  
Uniform Magnetic Field ◽  
Asymptotic Theory ◽  
Companion Paper ◽  
Mhd Equations ◽  
Alfven Wave ◽  
Large Reynolds Number ◽  
Plane Couette Flow

This paper aims to numerically verify the large Reynolds number asymptotic theory of magneto-hydrodynamic (MHD) flows proposed in the companion paper Deguchi (J. Fluid Mech., vol. 868, 2019, pp. 176–211). To avoid any complexity associated with the chaotic nature of turbulence and flow geometry, nonlinear steady solutions of the viscous resistive MHD equations in plane Couette flow have been utilised. Two classes of nonlinear MHD states, which convert kinematic energy to magnetic energy effectively, have been determined. The first class of nonlinear states can be obtained when a small spanwise uniform magnetic field is applied to the known hydrodynamic solution branch of plane Couette flow. The nonlinear states are characterised by the hydrodynamic/magnetic roll–streak and the resonant layer at which strong vorticity and current sheets are observed. These flow features, and the induced strong streamwise magnetic field, are fully consistent with the vortex/Alfvén wave interaction theory proposed in the companion paper. When the spanwise uniform magnetic field is switched off, the solutions become purely hydrodynamic. However, the second class of ‘self-sustained shear-driven dynamos’ at the zero external magnetic field limit can be found by homotopy via the forced states subject to a spanwise uniform current field. The discovery of the dynamo states has motivated the corresponding large Reynolds number matched asymptotic analysis in the companion paper. Here, the reduced equations derived by the asymptotic theory have been solved numerically. The asymptotic solution provides remarkably good predictions for the finite Reynolds number dynamo solutions.

Stability of the compressible viscous fluid around the plane Couette flow in the presence of a transverse uniform magnetic field

2018 ◽  
Vol 17 (01) ◽  
pp. 57-84
Author(s):  
Xingwei Zhang ◽  
Guojing Zhang ◽  
Hai-Liang Li
Keyword(s):  
Magnetic Field ◽  
Viscous Fluid ◽  
Couette Flow ◽  
Transverse Magnetic Field ◽  
Initial Perturbation ◽  
Three Dimensional ◽  
Transverse Magnetic ◽  
Plane Couette Flow ◽  
Compressible Viscous Fluid ◽  
The Stability

In this paper, we consider the stability of three-dimensional compressible viscous fluid around the plane Couette flow in the presence of a uniform transverse magnetic field and show that the uniform transverse magnetic field has a stabilizing effect on the plane Couette flow. Namely, for a sufficiently large Hartmann number, the compressible viscous plane Couette flow is nonlinear stable for small Mach number and arbitrary Reynolds number so long as the initial perturbation is small enough.

Zero absolute vorticity: Insight from experiments in rotating laminar plane Couette flow

2014 ◽  
Vol 89 (3) ◽  
Author(s):  
Alexandre Suryadi ◽  
Antonio Segalini ◽  
P. Henrik Alfredsson
Keyword(s):  
Couette Flow ◽  
Plane Couette Flow ◽  
Absolute Vorticity

Experiments in rotating plane Couette flow – momentum transport by coherent roll-cell structure and zero-absolute-vorticity state

2016 ◽  
Vol 791 ◽  
pp. 191-213 ◽  
Author(s):  
Takuya Kawata ◽  
P. Henrik Alfredsson
Keyword(s):  
Shear Stress ◽  
Secondary Flow ◽  
Couette Flow ◽  
Cell Structure ◽  
Normal Direction ◽  
Momentum Transport ◽  
Plane Couette Flow ◽  
Absolute Vorticity ◽  
Rotation Rates ◽  
Cell Structures

In spanwise rotating plane Couette flow (RPCF) a secondary flow dominated by three-dimensional roll-cell structures develops. At high enough rotation rates the flow exhibits a state of zero absolute vorticity at the centre of the channel, as described by Suryadi et al. (Phys. Rev. E, vol. 89, 2014, 033003). They suggested that the zero-absolute-vorticity state is caused by the secondary flow motion of the coherent roll-cell structure induced by the Coriolis force. In the present study we focus on the momentum transport caused by the roll-cell structure of laminar RPCF in order to further understand how the zero-absolute-vorticity state is maintained by the coherent roll cells. The flow is studied through stereoscopic particle image velocimetry measurements, which allow both the Reynolds shear stress and the wall shear stress to be quantified and used as measures of the momentum transport across the channel. Various types of roll-cell structures at different system rotation rates and the momentum transport induced by them are investigated, and the processes in which the momentum is transported in the wall-normal direction are discussed based on a displaced-particle argument as well as the production of the Reynolds stresses. It is shown that the wall-normal fluid motion driven by secondary flow of the roll-cell structure induces two different effects on the mean flow which conflict each other, the momentum transport in the wall-normal direction and the Coriolis acceleration, and the zero-absolute-vorticity state is a stable state where these two effects cancel each other.

DNS OF TURBULENT HEAT TRANSFER IN PLANE COUETTE FLOW

Equipment ◽  
2006 ◽  
Author(s):  
S. Hane ◽  
T. Tsukahara ◽  
K. Iwamoto ◽  
H. Kawamura
Keyword(s):  
Heat Transfer ◽  
Couette Flow ◽  
Turbulent Heat Transfer ◽  
Turbulent Heat ◽  
Plane Couette Flow
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