Role of suction/injection and slip flow on hydromagnetic free convective flow in a vertical coaxial cylinder under the influence of radial magnetic field

Heat Transfer ◽  
2021 ◽  
Author(s):  
Dauda Gambo ◽  
Jeremiah J. Gambo
Keyword(s):  
Magnetic Field ◽  
Convective Flow ◽  
Slip Flow ◽  
Coaxial Cylinder ◽  
Free Convective Flow ◽  
Radial Magnetic Field

The effect of radiation on free convective flow and mass transfer past a vertical isothermal cone surface with chemical reaction in the presence of a transverse magnetic field

2004 ◽  
Vol 82 (6) ◽  
pp. 447-458 ◽  
Author(s):  
A A Afify
Keyword(s):  
Magnetic Field ◽  
Mass Transfer ◽  
Boundary Conditions ◽  
Chemical Reaction ◽  
Transverse Magnetic Field ◽  
Convective Flow ◽  
Transverse Magnetic ◽  
Skin Friction Coefficient ◽  
Free Convective Flow ◽  
Cone Surface

The effects of radiation and chemical reactions, in the presence of a transverse magnetic field, on free convective flow and mass transfer of an optically dense viscous, incompressible, and electrically conducting fluid past a vertical isothermal cone surface are investigated. The nonlinear boundary-layer equations with the boundary conditions are transferred by a similarity transformation into a system of nonlinear ordinary differential equations with the appropriate boundary conditions. Furthermore, the similarity equations are solved numerically by using a fourth-order Runge–Kutta scheme with the shooting method. Numerical results for the skin-friction coefficient, the local Nusselt number, the local Sherwood number are given; as well, the velocity, temperature, and concentration profiles are presented for a Prandtl number of 0.7, the chemical-reaction parameter, the order of the reaction, the radiation parameter, the Schmidt number, the magnetic parameter, and the surface temperature parameter. PACS No.: 47.70.Fw

Theory and observations of switchbacks’ evolution in the solar wind

2021 ◽  
Author(s):  
Anna Tenerani ◽  
Marco Velli ◽  
Lorenzo Matteini
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Radial Magnetic Field ◽  
Open Questions ◽  
Coronal Activity ◽  
Turbulent Heating ◽  
Field Lines ◽  
Radial Evolution ◽  
Field Correlation

<p>Alfvénic fluctuations represent the dominant contributions to turbulent fluctuations in the solar wind, especially, but not limited to, the fastest streams with velocity of the order of 600-700 km/s. Alfvénic fluctuations can contribute to solar wind heating and acceleration via wave pressure and turbulent heating. Observations show that such fluctuations are characterized by a nearly constant magnetic field amplitude, a condition which remains largely to be understood and that may be an indication of how fluctuations evolve and relax in the expanding solar wind. Interestingly, measurements from Parker Solar Probe have shown the ubiquitous and persistent presence of the so-called switchbacks. These are magnetic field lines which are strongly perturbed to the point that they produce local inversions of the radial magnetic field. The corresponding signature of switchbacks in the velocity field is that of local enhancements in the radial speed (or jets) that display the typical velocity-magnetic field correlation that characterizes Alfvén waves propagating away from the Sun. While there is not yet a general consensus on what is the origin of switchbacks and their connection to coronal activity, a first necessary step to answer these important questions is to understand how they evolve and how long they can persist in the solar wind. Here we investigate the evolution of switchbacks. We address how their evolution is affected by parametric instabilities and the possible role of expansion, by comparing models with the observed radial evolution of the fluctuations’ amplitude. We finally discuss what are the implications of our results for models of switchback generation and related open questions.</p>

Sign in / Sign up

Export Citation Format

Share Document