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The study of fluid flow in cylindrical shapes under the effect of electric fields is of utmost importance because of its vast applications in industrial, agricultural, and biomedical domains, as well as in drilling machines, equipment, transport brakes, and vehicles. The purpose of this research is to analyze the influence of Hall impacts, slippage effects, and thermal relaxation time on the magnetohydrodynamic flow near an extended cylinder or flat plate. An assessment of entropy generation is carried out. Results are determined by the process of elongating a planar surface and a cylindrical object. The velocity field and entropy production are greater in the case of a stretched cylinder compared to a stretching flat plate. The choice of an appropriate stretching surface may have an impact on the thermal conductivity of the boundary layer. Velocity, temperature, and entropy are influenced by several factors including the Eckert number, thermal relaxation time, transverse curvature, magnetic field, Hall effect, molecular slip, and mixed convection parameters. These characteristics influence the movement of fluid, the transfer of heat, the measure of disorder (entropy), and the Bejan number. The variables mentioned cause changes in skin friction and Nusselt values. The Hall effect has advantages in reducing friction and enhancing heat transfer in industrial and technical processes. [ABSTRACT FROM AUTHOR]

The steady MHD boundary layer flow near the stagnation point over a stretching surface in the presence of the induced magnetic field, viscous dissipation, magnetic dissipation, slip velocity phenomenon, and heat generation/absorption effects has been investigated numerically. The Casson fluid model is used to characterize the non-Newtonian fluid behavior. The governing partial differential equations using appropriate similarity transformations are reduced into a set of nonlinear ordinary differential equations, which are solved numerically using a shooting method with fourth-order Runge-Kutta integration scheme. Comparisons with the earlier results have been made and good agreements were found. Numerical results for the velocity, induced magnetic field, temperature profiles, skin friction coefficient, and Nusselt number are presented through graphs and tables for various values of physical parameters. Results predicted that the magnetic parameter with α<1 has the tendency to enhance the heat transfer rate, whereas the reverse trend is seen with α>1. It is also noticed that the rate of heat transfer is a decreasing function of the reciprocal of a magnetic Prandtl number, whereas the opposite phenomenon occurs with the magnitude of the friction factor. [ABSTRACT FROM AUTHOR]

The current study focuses on the effect of Hall current on an unsteady free convection slip flow of a Casson fluid past an infinite vertical permeable plate in presence of variable suction. The non-linear coupled partial differential equations of the momentum and energy, which control the flow field, are converted into a system of ordinary differential equations using perturbation technique. The resulting equations are solved analytically with the objective of getting non-dimensional velocity and temperature fields. The study has also presented graphically the velocity and temperature profiles for different values of the parameters entering into the problem. Skin friction coefficient and Nusselt number which are of physical interest are sorted out and presented in the form of graphics. [ABSTRACT FROM AUTHOR]

Abstract: An analysis is performed to study the unsteady mixed convection flow of a viscous incompressible micropolar fluid adjacent to a heated vertical surface in the presence of viscous dissipation when the buoyancy force assists or opposes the flow. The flow of the fluid and subsequent heat transfer from the stretching surface is investigated with the aid of appropriate transformation variables. The effect of the governing parameters on the flow and heat transfer characteristics as well as the local skin friction coefficient, wall couple stress and the heat transfer rate are thoroughly examined. [Copyright &y& Elsevier]

The problem of a steady boundary layer MHD slip flow over a stretching sheet in a water-based nanofluid containing different type of nanoparticles: , and has been investigated. An external strong magnetic field is applied perpendicular to the plate and the Hall effect is taken into consideration. The surface of the stretching sheet is assumed to move with a linear velocity and subject to power-law variation of the surface temperature. The governing partial differential equations are transformed into nonlinear ordinary differential equations using a similarity transformation, before being solved numerically by a Runge-Kutta-Fehlberg method with shooting technique. Effects of the physical parameters on the primary velocity, the secondary velocity and the temperature as well as on the wall shear stress and the rate of heat transfer have been presented graphically and discussed in detail. Investigated results indicate that the nanoparticle volume fraction and the slip parameter produce opposite effects on the skin friction coefficients of the primary and secondary flow. Also, the nanoparticle volume fraction and the types of nanoparticles demonstrate a more pronounced influence on the secondary flow than that on the primary flow and temperature distribution. [ABSTRACT FROM AUTHOR]

Abstract: The effect of radiation on the heat and fluid flow over an unsteady stretching surface is analyzed. Using a similarity transformation the governing time dependent boundary layer equations for momentum and thermal energy are reduced to a set of ordinary differential equations. The resulting three-parameter problem is solved numerically for some representative values of the unsteadiness parameter A, the radiation parameter R and Prandtl number Pr. It is shown that the heat transfer rate is increased with increasing R, A and Pr. Also the effect of radiation parameter on the heat transfer rate is found to be more noticeable at larger values of A and Pr. [Copyright &y& Elsevier]

Micropolar boundary-layer flow and heat transfer characteristics associated with a heated exponential stretching continuous sheet being cooled by a mixed convection flow are examined. The relevant heat transfer mechanisms are of interest in a wide variety of practical applications such as hot rolling, continuous casting, extrusion, and drawing. The wall temperature and stretching velocity are assumed to vary according to specific exponential forms. The contributions of buoyancy along with viscous dissipation on the convective transport in the boundary-layer region is analyzed in the opposing and assisting flow situations. Local similarity solutions are obtained for the boundary-layer equations governing the problem. A parametric study of the mixed convection parameter ξ, the micropolar parameter Δ, the Eckert number Ec, the parameter of temperature distribution n, and Prandtl number Pr is conducted and a representative set of numerical results for the velocity, angular velocity, temperature profiles, local skin friction coefficient, wall couple stress parameter, and local Nusselt number are illustrated graphically to show typical trends of the solutions. [ABSTRACT FROM AUTHOR]