Presence Of Lorentz Force Research Articles

Numerical study of MHD mixed convection flow over a diamond-shaped obstacle using OpenFOAM

The development of the flow structure with assisting the buoyancy in the liquid metal flow over the diamond-shaped obstacle and the influence of the presence of magnetic field on the vorticity and heat dissipation from the hot surface is investigated numerically at fixed Reynolds number of Re = 1000. The computation is performed by the in-house developed magnetohydrodynamics (MHD) based flow solver using open source CFD tool OpenFOAM. The liquid metal with a Prandtl number of Pr = 0.02 is considered as working fluid and is assumed to be electrically conducting in nature. The strength of the buoyancy in the flow is varied in the range of four different Richardson number of Ri = 0, 0.5, 1, and 5. The consequence of the rising buoyancy in the flow on the vorticity and time-averaged Nusselt number over the hot surface is observed. The unsteadiness in the flow due to the rise in the buoyancy is further controlled and regulated by the application of a magnetic field. The intensity of the magnetic field is governed by non-dimensional Hartmann number (Ha) varies in the range of Ha = 0–50. It is observed from the results that the Lorentz force in the flow opposes the Kármán vortex street and the buoyancy in the flow degenerates the vortex. The undulation in the heat transfer due to rise in the buoyancy is suppressed by the presence of Lorentz force without sacrificing the Nusselt number at low Hartmann number. The study of isotherms, streamlines, time-averaged Nussselt number, vorticity is discussed in detail.

Influence of Chemical Reaction on Marangoni Convective Flow of Nanoliquid in the Presence of Lorentz Forces and Thermal Radiation: A Numerical Investigation

Influence of Chemical Reaction on Marangoni Convective Flow of Nanoliquid in the Presence of Lorentz Forces and Thermal Radiation: A Numerical Investigation

Second Law Analysis of Dissipative Nanofluid Flow over a Curved Surface in the Presence of Lorentz Force: Utilization of the Chebyshev⁻Gauss⁻Lobatto Spectral Method.

The primary objective of the present work is to study the effects of heat transfer and entropy production in a nanofluid flow over a curved surface. The influences of Lorentz force and magnetic heating caused by the applied uniform magnetic field and energy dissipation by virtue of frictional heating are considered in the problem formulation. The effects of variable thermal conductivity are also encountered in the present model. The dimensional governing equations are reduced to dimensionless form by introducing the similarity transformations. The dimensionless equations are solved numerically by using the Chebyshev–Gauss–Lobatto spectral method (CGLSM). The rate of increase/increase in the local Nusselt number and skin friction coefficient are estimated by using a linear regression model. The expression for dimensionless entropy production is computed by employing the solutions obtained from dimensionless momentum and energy equations. Various graphs are plotted in order to examine the effects of physical flow parameters on velocity, temperature, and entropy production. The increase in skin friction coefficient with magnetic parameter is high for nanofluid containing copper nanoparticles as compared to silver nanoparticles. The analysis reveals that velocity, temperature, and entropy generation decrease with the rising value of dimensionless radius of curvature. Comparative analysis also reveals that the entropy generation during the flow of nanofluid containing copper nanoparticles is greater than that of containing silver nanoparticles.

Nanofluid heat transfer in a porous duct in the presence of Lorentz forces using the lattice Boltzmann method

The magnetohydrodynamic (MHD) flow of a nanofluid through a permeable duct was analyzed via the mesoscopic approach. The lattice Boltzmann method (LBM) was selected to portray the impacts of magnetic (Ha) , Reynolds (Re) and Darcy (Da) numbers on the nanofluid behavior. Copper oxide nanoparticles were dispersed into H2O. The properties of the fluid were predicted considering Brownian motion. Outputs illustrate that a thinner thermal boundary layer can be seen with augment of Da and Ra . Employing a magnetic field can enhance the Nuave.

Impact of Soret and Dufour Numbers on MHD Casson Fluid Flow Past an Exponentially Stretching Sheet with Non-Uniform Heat Source/Sink

Present study deals with the impact of cross diffusion on Casson fluid flow in the presence of Lorentz force. Flow is caused by the exponential stretching of surface in two lateral directions. The influence of space dependent varying heat sink/source is also contemplated. The basic governing equations are first converted into system of ODEs and then solved using an efficient numerical procedure namely R.K. based shooting technique. From the solution we found that flow is affected by some physical parameters like Casson parameter, non uniform heat parameters, Soret and Dufour numbers etc. Hence the impact of such parameters on velocity, temperature and concentration profiles is shown via plots. Further the friction factor, local Nusselt and Sherwood numbers are also calculated and given in tables. Results indicate that an increase in the Casson parameter enhances the temperature and concentration fields. Dufour and Soret numbers have tendency to enhance temperature and concentration fields respectively.

Effect of dispersing nanoparticles on solidification process in existence of Lorenz forces in a permeable media

In current article, Lorentz forces influence on NEPCM solidification phenomena in a storage porous unit is reported with numerical method via FEM. Nanotechnology and magnetic field are employed to expedite this unsteady process. Roles of Hartmann number, Rayleigh number and volume fraction of NEPCM have been reported. Outputs reveal that solid fraction rises in presence of Lorentz forces. Full discharging time reduces with augment of volume fraction of CuO-water and Hartmann number.

Influence of Lorentz force, Cattaneo-Christov heat flux and viscous dissipation on the flow of micropolar fluid past a nonlinear convective stretching vertical surface

AbstractThe problem of micropolar fluid flow over a nonlinear stretching convective vertical surface in the presence of Lorentz force and viscous dissipation is investigated. Due to the nature of heat transfer in the flow past vertical surface, Cattaneo-Christov heat flux model effect is properly accommodated in the energy equation. The governing partial differential equations for the flow and heat transfer are converted into a set of ordinary differential equations by employing the acceptable similarity transformations. Runge-Kutta and Newton’s methods are utilized to resolve the altered governing nonlinear equations. Obtained numerical results are compared with the available literature and found to be an excellent agreement. The impacts of dimensionless governing flow pertinent parameters on velocity, micropolar velocity and temperature profiles are presented graphically for two cases (linear and nonlinear) and analyzed in detail. Further, the variations of skin friction coefficient and local Nusselt number are reported with the aid of plots for the sundry flow parameters. The temperature and the related boundary enhances enhances with the boosting values of

CuO-water nanofluid flow due to magnetic field inside a porous media considering Brownian motion

Homogeneous nanofluid flow and forced convection heat transfer inside a lid driven porous cavity is investigated in presence of Lorentz forces. Brownian motion and shape factor influence on nanofluid treatment are taken into consideration. CVFEM is employed to simulate the vorticity stream function formulation. Outputs are demonstrated the roles of Darcy number (Da), Hartmann number (Ha), Reynolds number (Re) and CuO-water volume fraction (ϕ). Results illustrate that the shapes of CuO nanoparticles can change the thermal behavior of nanofluid and greatest Nusselt number is obtained when Platelet shaped nanoparticles has been utilized. Convective heat transfer improves with augment of Darcy and Reynolds number but it reduces with rise of Hartmann number.

Analytical approach for the effect of melting heat transfer on nanofluid heat transfer

In this article, the impact of melting heat transfer on nanofluid flow in the presence of Lorentz forces is reported. Different shapes of nanoparticles are considered. The impacts of Joule heating, viscous dissipation and thermal radiation are added in the governing equations. The Homotopy Analysis Method (HAM) is selected to solve Ordinary Differential Equations (ODEs). The roles of nanofluid volume fraction, shape of the nanoparticles, Hartmann number, porosity parameter, melting parameter, Eckert number are presented graphically. The results reveal that choosing a platelet shape leads to the maximum Nusselt number. The temperature reduces with the rise of the melting parameter but velocity increases with the increase of the melting parameter. Nu augments with the increase of the Lorentz forces while it reduces with the augment of porosity and melting parameters.

Influence of melting surface on MHD nanofluid flow by means of two phase model

In this paper, the effect of melting heat transfer on the nanofluid flow in the presence of Lorentz forces is reported. Two phase model is considered for the nanofluid. The Runge–Kutta method is selected to solve the ODEs, which are obtained from a similarity transformation. The roles of the Reynolds number, Schmidt number, Brownian parameter, thermophoresis parameter, Eckert number and melting parameter are illustrated graphically. The results reveal that the Nusselt number increases with an increase of the Hartmann number. The temperature gradient reduces with a rise of the melting parameter and Eckert number.

Effects of Viscous Dissipation and Double Stratification on MHD Casson Fluid Flow over a Surface with Variable Thickness: Boundary Layer Analysis

In this article, the motion of two-dimensional Casson fluid flows with temperature dependent plastic dynamic viscosity together with double (i.e. thermal and solutal) stratification in the presence of Lorentz force is investigated. The case where the viscosity of the fluid tends to take energy away from the motion (kinetic energy) and transform it into internal energy is considered. The nonlinear governing equations and their associated boundary conditions are transformed and non-dimensionalized using similarity variables which are thereafter solved numerically using the shooting method together with the Runge-Kutta technique. The effects of the magnetic field parameter, temperature dependent viscosity parameter, Casson parameter, Eckert number, velocity power index, pressure gradient parameter and wall thickness parameter on the velocity, temperature, and concentration profiles are showed graphically and discussed. Substantial increase in temperature distribution is certain with an increase in the magnitude of Eckert number. Local skin friction coefficient decreases with an increase in pressure gradient parameter.

Transportation of MHD nanofluid free convection in a porous semi annulus using numerical approach

Nanofluid free convection in presence of Lorentz forces in a permeable semi annulus is simulated using Control Volume based Finite Element Method. Impact of porous media on governing equations is considered by means of Darcy law. Brownian motion impact on properties of nanofluid is taken into account using Koo-Kleinstreuer-Li (KKL) model. Important parameters are inclination angle (ξ), CuO-water volume fraction (ϕ), Hartmann (Ha) and Rayleigh (Ra) numbers for porous medium. A formula for Nuave is provided. Results indicated that temperature gradient detracts with enhance of Ha but it enhances with rise of ξ,Ra. Heat transfer augmentation enhances with rise of Lorentz forces.

Reflection of a plane magneto-thermoelastic wave at the boundary of a solid half-space in presence of initial stress

The paper studies the effects of the magnetic field and initial stress on the reflection of a plane magneto-thermoelastic wave from the boundary of a solid half-space. The basic dynamical equations of thermoelasticity in presence of Lorentz force and the heat conduction equation of Green–Lindsay theory have been solved to derive the wave equations for the reflected P-, SV- and thermal waves. By considering the boundary to be a stress-free and insulated one, the boundary equations that contain the ratios of the amplitude of the reflected components to that of the incident wave have been obtained. The analytical solution has been cast in matrix form for each of the incident plane waves at the boundary, namely the P-wave, SV-wave and thermal wave. The numerical calculations of the absolute values of the amplitude ratios for an incident SV-wave have been carried out for different values of both magnetic pressure number and initial stress parameter. The initial stress parameter shows a marked influence on the magnitude of the amplitude ratios. The reflection coefficients for different values of magnetic pressure number in absence of initial stress have also been included for the sake of comparison.

Deflection of a liquid metal jet/drop in a tokamak environment

The interaction of a liquid gallium jet with plasma has been investigated in the ISTTOK tokamak. The jet was observed to remain intact during its interaction with plasma, within a certain length beyond which drop formation was observed. Significant deflection of the jet was detected as soon as plasma production was started. Furthermore, a strong dependency of the deflection magnitude on plasma position was observed that could be correlated with plasma potential gradients. As a means to capture and, possibly, quantify this effect, a preliminary magnetohydrodynamic analysis was performed in order to predict the trajectory of a jet that is traveling inside an electromagnetic field. The effect of Lorentz forces, gravity and pressure drop are accounted for in a unidirectional model that assumes a small jet radius in comparison with the trajectory length. The effect of external electric potential gradients on jet deflection was ascertained in conjunction with the importance of electric stresses in modulating the jet speed and radius. Analysis of the results reported in the ISTTOK experiments identifies the process of jet break-up as a capillary instability. The trajectory of the ensuing droplets is modeled and intensification of the deflection process is predicted in the presence of Lorentz forces.

Dynamics of inertial vortices in multicomponent Bose-Einstein condensates

With use of the nonlinear Schr{\"o}dinger (or Gross-Pitaevskii) equation with strong repulsive cubic nonlinearity, dynamics of multi-component Bose-Einstein condensates (BECs) with a harmonic trap in 2 dimensions is investigated beyond the Thomas-Fermi regime. In the case when each component has a single vortex, we obtain an effective nonlinear dynamics for vortex cores (particles). The particles here acquire the inertia, in marked contrast to the standard theory of point vortices widely known in the usual hydrodynamics. The effective dynamics is equivalent to that of charged particles under a strong spring force and in the presence of Lorentz force with the uniform magnetic field. The inter-particle (vortex-vortex) interaction is singularly-repulsive and short-ranged with its magnitude decreasing with increasing distance of the center of mass from the trapping center. "Chaos in the three-body problem" in the three vortices system can be seen, which is not expected in the corresponding point vortices without inertia in 2 dimensions.

Relaxation effects on reflection of generalized magneto-thermoelastic waves

The paper studies the effects of the magnetic field and initial stress on the reflection of a plane magneto-thermoelastic wave from the boundary of a solid half-space. The basic dynamical equations of thermoelasticity in presence of Lorentz force and the heat conduction equation of Green–Lindsay theory have been solved to derive the wave equations for the reflected P-, SV- and thermal waves. By considering the boundary to be a stress-free and insulated one, the boundary equations that contain the ratios of the amplitude of the reflected components to that of the incident wave have been obtained. The analytical solution has been cast in matrix form for each of the incident plane waves at the boundary, namely the P-wave, SV-wave and thermal wave. The numerical calculations of the absolute values of the amplitude ratios for an incident SV-wave have been carried out for different values of both magnetic pressure number and initial stress parameter. The initial stress parameter shows a marked influence on the magnitude of the amplitude ratios. The reflection coefficients for different values of magnetic pressure number in absence of initial stress have also been included for the sake of comparison.