Unsteady Magnetohydrodynamic Flow Research Articles

Hall effect on unsteady MHD flow along vertical plate with variable temperature and mass diffusion in the presence of porous medium and chemical reaction

The effects of chemical reaction and Hall current on the unsteady magneto hydrodynamic flow along a vertical plate with variable temperature and mass diffusion in the presence of a porous medium is studied hare. The fluid flow model of this paper contains governing partial differential equations of the motion, energy, and diffusion equation. To simplify the analysis, the governing equations are transformed into dimensionless form using non-dimensional variables. The Laplace-transform technique is employed to obtain an exact solution for the flow equations of the MHD model. The results of the analysis are presented using graphical representations of the velocity profiles. With the help of graphs, we discussed the behavior of fluid velocities with different parameters, including the chemical reaction parameter, Hall cur-rents parameter, accelerated parameter, magnetic field parameter, and permeability parameter, and the numerical values of Sherwood number have been tabulated. We found that the values obtained for velocity, concentration and temperature are in concurrence with the actual flow of the fluid.

Bioconvection effects on the heat and mass transfer of unsteady MHD blood flow over a permeable artery

The mathematical analysis of blood’s non-Newtonian behavior in the presence of drug nanoparticles and microbes with magnetic and thermal radiation effects is the focus of the current article. The response surface methodology (RSM) is used to conduct a sensitivity study of the bioconvection impacts on the heat and mass transmission rate of the unsteady magnetohydrodynamic blood flow. The physical laws governing unsteady blood flow over stretching blood vessels are mathematically represented as a system of partial differential equations, which are numerically solved using the Fourth Order Runge–Kutta Method in conjunction with the Shooting Technique. Following an analysis of the numerical data, statistical conclusions are drawn on the heat and mass transfer rates. The impact of Brownian motion and thermophoresis factors is discovered to increase blood temperature. Additionally, at the largest Brownian motion factor and maximum thermophoresis effect, the largest heat transfer rate occurs. It is also observed that the lowest mass transfer rates are generated by higher radiation parameter and chemical reaction parameter values. The findings of the study show potential for important applications in therapeutic hypothermia, magnetic therapy, and targeted drug delivery.

Parameter estimation for unsteady MHD oscillatory free convective flow of generalized second grade fluid with Hall effects and thermal radiation effects

This work first establishes an unsteady magnetohydrodynamic (MHD) oscillatory free convection flow model of the generalized second grade fluid with Hall heat and mass transfer effect in a straight rectangular duct. A fast second-order spectral method with fractional backward difference formula (FBDF) is proposed to obtain the numerical solution of the established model. The distribution of the velocity and the temperature fields is discussed, and the effect of each parameter on the velocity and temperature fields is shown through graphical experiments. Moreover, in order to avoid the problems of slow computational speed and low accuracy of traditional numerical methods, new fractional physics-informed neural networks (PINNs) are proposed for the multi-parameter estimation of this model. At the same time, a comparative study of our method with the Bayesian method is presented. Experimental results show that fractional PINNs is more effective for multi-parameter estimation problems and get better accuracy at the same number of parameters.

Effectiveness of silver-magnesium oxide-water hybrid nanofluid in Couette channel

The present article numerically investigates the unsteady magnetohydrodynamic (MHD) Couette flow containing novel (Ag + MgO)-water hybrid nanofluid (HNF). The nanoparticles of silver (Ag) and magnesium oxide (MgO) are supplemented to base fluid water. The top wall is kept in uniform motion while the bottom wall of channel set stationary and stretchable. An external magnetic field is applied perpendicular to lower plate. The governed nonlinear partial differential equations (PDE) are solved employing finite difference method (FDM). The effects of hybrid nanofluid and nanofluid (NF) are compared for the significant parameters and presented graphically. The results illustrate that (Ag + MgO)-water HNF exhibits significant influence over Ag-water NF on velocity and temperature in the Couette channel.

Radiation Absorption and Diffusion Thermo Effects on Unsteady MHD Kuvshinski Fluid Flow Past an Inclined Porous Plate in the Presence of Thermal Radiation and Chemical Reaction

The aim of the present paper is to investigate investigated the Radiation absorption and diffusion thermo on unsteady magneto hydrodynamic Kuvshinski fluid flow past an infinite vertical permeable moving plate in Presence of thermal radiation, heat absorption and homogenous chemical reaction, subjected to variable suction. The plate is assumed to be embedded in a uniform porous medium and Moves with a constant velocity in the flow direction in the presence of a transverse magnetic Field. The equations governing the flow are transformed into a system of nonlinear ordinary differential equations by using perturbation technique. Graphical results for the velocity distribution, temperature distribution and concentration distribution based on the numerical solutions are presented and discussed. Also discuss the effects of various parameters on the skin-friction coefficient and the rate of heat transfer in the form of Nusselt number and rate of mass transfer in the form of Sherwood number at the surface. Velocity and temperature distribution is observed to increase with an increase in Radiation absorption and Dufour parameter, whereas diminishes with enhances of Magnetic field, heat absorption coefficient, radiation parameter and chemical reaction parameter in respective velocity, temperature and concentration distributions.

Radiation Absorption and Diffusion Thermo Effects on Unsteady MHD Casson Fluid Flow Past a Moving Inclined Plate Embedded in Porous Medium in the Presence of Chemical Reaction and Thermal Radiation

The aim of the present paper is to investigate the effects of Radiation absorption and diffusion thermo on unsteady magnetohydrodynamic Casson fluid flow past an inclined permeable moving plate in Presence of thermal radiation, heat absorption and homogenous chemical reaction. The plate is assumed to be embedded in a uniform porous medium and Moves with a constant velocity in the flow direction in the presence of a transverse magnetic Field. The equations governing the flow are transformed into a system of nonlinear ordinary differential equations by using perturbation technique. Graphical results for the velocity distribution, temperature distribution and concentration distribution based on the numerical solutions are presented and discussed. Also discuss the effects of various parameters on the skin-friction coefficient and the rate of heat transfer in the form of Nusselt number and rate of mass transfer in the form of Sherwood number at the surface. Velocity and temperature distribution is observed to increase with an increase in radiation absorption and Dufour parameter, whereas diminishes with enhances of Magnetic field, heat absorption coefficient, radiation parameter and chemical reaction parameter in respective velocity, temperature and concentration distributions.

A numerical study on MHD Cu-Al2O3/H2O hybrid nanofluid with Hall current and cross-diffusion effect

A numerical investigation has been performed to analyze an unsteady magnetohydrodynamic gravity-driven flow of a Newtonian hybrid nanofluid (Cu-Al2O3/H2O) along an impermeable vertical plate with linearly accelerated temperature and concentration. The Hall current, nanoparticle volume fraction, inclined magnetic field, and Soret effect on water-based Cu-Al2O3 hybrid nanofluid are incorporated into the flow model. The model's governing nonlinear partial differential equations are formulated and transformed into a non-dimensional form by introducing suitable variables and parameters. The finite difference method is implemented via the MATLAB solver fsolve to resolve the model equations numerically. The evolution of the primary and secondary velocities, temperature, and species concentration profiles is discussed via graphical illustration. Furthermore, a comparative analysis is performed on the coefficient of skin friction, rate of heat, and mass transport for hybrid nanofluid and nanofluid through tabular values. The novelty of the investigation reveals that a deceleration in the primary velocity and acceleration in the secondary velocity with the increasing magnetic field inclination parameter exists. The rising value of Cu nanoparticle volume fraction augments the primary, secondary skin friction coefficients, and the heat and mass transport rates at the plate. The Dufour number stimulates a reduction in the heat transport rate, while an enhancement occurs with the Soret number. The present investigation demonstrates that the heat transfer rate for water-based Cu-Al2O3 hybrid nanofluid is higher than that for water-based Cu nanofluid. The current research can be implemented to augment the efficiency of the cooling mechanism of heat exchangers, solar collectors, nuclear reactors, and many more.

Magneto-Thermo Heat Transfer of a Chemically Reactive and Viscous Dissipative Casson Nanofluid Thin Film Over an Unsteady Stretching Surface with Variable Thermal Conductivity

This paper addressed unsteady magnetohydrodynamic flow and heat transfer of an incompressible Casson nanofluid thin film past a stretching sheet by considering the features of thermal radiation, chemical reaction, and viscous dissipation. The problem is modeled mathematically, and the governing basic equations are brought into nonlinear ordinary differential equations by utilizing appropriate similarity transformations. Then the transformed equations are then solved numerically by using the bvp4c solver. The influences of pertinent physical variables are performed on velocity, temperature gradient, and nanoparticle concentration gradient profiles. It is seen that the profile of the nanoparticle concentration gradient enhances by increasing the values of the Schmidt number, whereas the opposite trends are observed by increasing the values of the thermophoresis parameter. It is also analyzed that by increasing the values of the thermophoresis parameter, there is an increase in the profiles of the temperature and concentration distributions. The computed results are obtained by giving main consideration to the convergence process and comparing them with the results existing in the literature.

English

English

Investigation of the effects of various nanoparticle morphologies on mass and heat transport in SiO2-H2O unsteady magnetohydrodynamic nanofluid flow through a stretched cylinder

This article investigates the effects of the various silicon dioxide ( Si O 2 ) nanoparticles immersed in water ( H 2 O ) base fluid on velocity and heat transport over an unsteady stretching cylinder under the influence of magnetohydrodynamics ( MHD ), velocity slip, and convective boundary conditions. The physical model is initially developed in the form of partial differential equations (PDEs) by using the conservation principle. Employing suitable transformations, the set of PDEs has been transformed into a system of Ordinary differential equations (ODEs). The nonlinear equations in the proposed model are optimally and dynamically assessed. To produce numerical solutions for nonlinear systems, MATLAB's BVP4C solver technique is used. Furthermore, the numerical technique is validated by calculating residual error. The recent investigation’s novel results include: the nanoparticles SiO 2 of play an important role in enhancing the thermal conductivity of the traditional base fluid H 2 O . The shape of the nanoparticles also plays a remarkable role in heat transfer enhancement. Increases in viscus dissipation, convective boundary conditions, and MHD parameters play a remarkable role in increasing the temperature of the nanofluid. Furthermore, platelet-shaped Si O 2 nanoparticles are reported to have the highest flow rate, highest temperature, and highest value of Nusselt numbers.

Inherent irreversibility in unsteady magnetohydrodynamic nanofluid flow past a slippery permeable vertical plate with fractional-order derivative

Abstract This study focuses on fractional-order derivatives for the unsteady flow of magnetohydrodynamic (MHD) methanol-iron oxide (CH3OH-Fe3O4) nanofluid over a permeable vertical plate. The utilization of fractional-order derivatives provides a mathematical representation of the flow model. The concluding model, consisting of a system of fractional-order transient partial differential equations, has been solved using the finite difference method, and graphical illustrations demonstrate the effects of key parameters on the flow field. Velocity and temperature profiles provide insights into nanofluid behavior. Additionally, essential quantities such as skin friction coefficient, Nusselt number, Bejan number, and entropy generation rate have been depicted graphically. Comparison with previous studies authenticates the accuracy of the anticipated model, contributing to new intuitions into MHD nanofluid flow over a permeable vertical plate. It is worth noting that the current model, incorporating fractional-order derivatives, contributes to understanding the physical characteristics of MHD CH3OH-Fe3O4 nanofluid flow over a permeable vertical plate, research that has not been extensively explored before.

Unsteady thin film radiative nanofluids flow over time-dependent inclined stretching surfaces with Lorentz force and heat generation

This study aims to explore the unsteady magnetohydrodynamic thin film nanofluids flow over an inclined stretching surface in the presence of thermal radiation. The stretching velocity, Lorentz force and heat generation impacts together with the distributions of the temperature and nanoparticles at the surface are considered time-dependent. During the problem formulation, the haphazard motion and thermal migration are not neglected. The solution methodology is based on the Runge–Kutta method and it is divided into two steps, namely, solution of the momentum equations to obtain the nanofluid film thickness [Formula: see text] corresponding to the unsteadiness parameter S and the second step is using the values of [Formula: see text] to solve the entire system of equations. The major findings revealed that the nanofluid film thickness [Formula: see text] is reduced as the unsteadiness and magnetic field parameters are growing. Also, the rate of the heat transfer is diminishing as either the radiation parameter or the inclination angle increases. Furthermore, the increase in the buoyancy parameter from 0 to 1.5 gives an enhancement in the velocity up to 0.63%.

Unsteady Williamson Fluid Flow Over Exponentially Stretching Sheet in the presence of Non-Uniform Heat Generation or Absorption and Inclined Magnetic Field

The effect of an inclined magnetic field on unsteady magneto hydrodynamic Williamson fluid flow past an exponentially stretching sheet with joule heating, non-uniform heat generation or absorption, and suction or blowing is investigated numerically in this work. The reduced non-linear ordinary differential equations are obtained from governing partial differential equations using appropriate similarity transformations. The reduced equations are then solved with the help of bvp4c in MATLAB. The effects of various physical parameters on velocity, temperature and concentration profile, skin friction coefficient, Nusselt, and Sherwood number are described through graphs and tables. The result indicates that the rising values of the Weissenberg number decrease the velocity profile and increase the temperature and concentration profiles. It is also found that an inclined magnetic field reduces fluid velocity.

Heat transfer analysis of unsteady MHD slip flow of ternary hybrid Casson fluid through nonlinear stretching disk embedded in a porous medium

The original article's purpose is to assess transfer of heat exploration for unsteady magneto hydrodynamic slip flow of ternary hybrid Casson fluid via a nonlinear flexible disk placed within a perforated medium of a magnetic field in the presence. Unsteady nonlinearly stretched disk inside porous material causes flow to occur. In the investigation, convective circumstances on wall temperature are also considered. The governing equations (PDEs) are transformed into ordinary differential equations (ODEs) using appropriate transformations, and the Keller-box technique is employed for their solution. In forced convection, the variable radiation has no direct impact on fluid velocity, but it is noticed that in the case of aiding flow, fluid velocity rises with an increase in radiation parameter, and the opposite is true in the case of opposing flow. Furthermore, it is experiential that fluid concentration and velocity goes up in creative chemical reactions, and both profiles decrease in detrimental chemical reactions. Moreover, a slightly greater unsteadiness characteristic lowers fluid, concentration, temperatureand velocity. Physical parameters' effects on fluid temperature, concentration, and velocity, as well as on wall shear stress, energy, and mass transfer rates, are studied.

Numerical and sensitivity study on the heat transfer due to bioconvection on unsteady radiative MHD blood flow over a permeable artery with chemical reaction effects

The primary goal of this research is to investigate the dynamics of nanoparticle-mediated blood flow in the presence of bioconvection effects caused by microorganisms. The boundary layer problem of unsteady magnetohydrodynamic blood flow in the porous medium of tissues in stretching motion is studied. The Casson fluid model of blood flow is mathematically represented by a system of partial differential equations (PDE). The resulting set of governing equations is numerically solved, and the physical interpretation is given for the outcomes that are presented as graphs and tables. The temperature and concentration distribution of blood, along with the organism density profile in the corresponding boundary layer, are plotted, and the effects of various physical parameters, including magnetic field, radiation, chemical reaction, and permeability of the porous medium, on the results are investigated. Additionally, physical effects on the heat and mass transfer coefficients of the flow are also discussed. It is observed that the rate of heat transfer and the temperature profile are improved by increasing the values of the thermophoresis and Brownian motion parameters. Furthermore, at the lowest value of the permeability parameter and the highest value of the Brownian motion factor, the maximum heat transfer rate is observed. The findings of the study bear the promise of significant application in targeted drug delivery, magnetic therapy, and therapeutic hyperthermia treatments.

Unsteady natural-convection MHD flow of the generalized Maxwell fluid past a canted porous plate

The natural-convection magnetohydrodynamic (MHD) flow usually takes place in the process of many industries, such as astrophysics and electronics. In this work, the MHD flow characteristic and heat behavior about the generalized Maxwell fluid passing the canted porous plate under the titled magnetic field is investigated, which is stemmed from the effect of the heat absorption, thermal radiation, the first-order chemical reaction and radiation absorption. And for the temperature and concentration, we established the single-phase-lag model to describe the anomalous transported process. By utilizing the Laplace-transform (L-T) and Fourier-sine transform (F-ST), the solutions in the transformed domain about velocity, temperature, concentration are given analytically. Then the semi-analytical solution can be denoted via the inverse F-ST and numerical inverse L-T. Further, the cognate parameters’ impacts on the solution are discussed and the results are displayed intuitively via profiles.

Influences of conservative and non-conservative Lorentz forces on energy conservation properties for incompressible magnetohydrodynamic flows

In the analysis of magnetohydrodynamic (MHD) flow, the Lorentz force significantly affects energy properties because the work generated by the Lorentz force changes the kinetic and magnetic energies. Therefore, the Lorentz force and energy conversion should be predicted accurately. Some energy conservation schemes have been proposed and validated. However, the influences of the Lorentz force discretization on conservation and conversion of energy have not yet been clarified. In this study, a conservative finite difference method is constructed for incompressible MHD flows considering the induced magnetic field. We compare the difference in energy conservation properties among three methods of calculating the Lorentz force. The Lorentz forces are calculated in conservative and non-conservative forms, and both compact and wide-range interpolations of magnetic flux density are used to calculate the non-conservative Lorentz force. The compact interpolation method proposed in this study can perform conversions between conservative and non-conservative forms of the Lorentz force even when using the finite difference method. The present numerical method improves the conservation of transport quantity. Five models were analyzed, and the accuracy and convergence of the present numerical method were verified. From the viewpoint of the conservation of the total energy in an ideal inviscid periodic MHD flow, we consider that the calculation using compact interpolation for the Lorentz force is appropriate. This method preserves the total energy even on non-uniform grids. Moreover, the divergence-free condition of the magnetic flux density is discretely satisfied even without the correction of the magnetic flux density. The present numerical method can capture the Hartmann layer in the propagation of an Alfvén wave and accurately predict the tendency of energy attenuation in the analysis of a Taylor decaying vortex under magnetic fields. Analysis of the Orszag–Tang vortex reveals energy dissipation processes and the generation of high current densities. The present numerical method has excellent energy conservation properties and can accurately predict energy conversion. Therefore, this method can contribute to understanding complex unsteady MHD flows.

3D MHD analysis of prototypical manifold for liquid metal blankets

The water-cooled lead lithium (WCLL) and the dual-cooled lead lithium (DCLL) are two of the breeding blanket (BB) concepts that the EUROfusion consortium is pursuing in the framework of the development of the fusion reactor industrial demonstrator DEMO. Both involve the use of a liquid metal (LM) as working fluid, the lead-lithium eutectic alloy (PbLi), due to its excellent thermal properties and the possibility to serve as both the blanket coolant and tritium breeder and carrier. Unfortunately, due to the high electrical conductivity of LMs, their motion is influenced by the magnetic field used in the reactor to confine the plasma, generating a complex phenomenology which is studied by magnetohydrodynamics (MHD). In this work, a representative prototypical manifold of a BB bottom feeder is investigated for different configurations with the custom phiFoam solver, capable of simulating unsteady, incompressible and isothermal MHD flow. The aim of this study is to investigate which configuration minimizes the flow imbalance in the manifold for the WCLL or in the poloidal breeding zone channels for the DCLL. The distribution of the flow rate among the channels is strongly influenced by the position of the feeding pipe (FP) and by the development of the MHD internal layer near the expansion, which generates important jets close to the lower plate and the upper one, where the channels are attached. The channel aligned with the FP is the one carrying most of the flow, from 55% to 82%, while in the more distant one the flow is almost stagnant, carrying from 17% to 6% of the total flow rate. The total pressure loss is also estimated and its functional dependence on the manifold configuration is discussed.

Significance of induced magnetic field and thermal radiation: Dynamics of Newtonian fluids subject to viscous dissipation due to temperature gradient

This work is focused on Magneto hydrodynamic unsteady flow of Newtonian fluid flow over a perpendicular porous plate along with chemical reaction, heat, and mass transfer. The induced magnetic field and viscous and magnetic dissipation properties are considered throughout the porous plate. Heat source is the added effect in the model to observe the nature of flow in this work. This study finds its applications in understanding the storage of flues, disposal of radioactive waste materials, flow in water purifies, etc. The nonlinear behavior of the governing equation motivates us to use a finite difference approach for solving equations. The major resolution of this research is to work on how the physical elements affect velocity, temperature, concentration, and magnetic field. Fascinating facts are noticed as the unsteady fluid velocity rises with the heat source parameter because as the heat of a material increases, the movement of the fluid particle will be fast. Due to the presence of a magnetic field high thermal radiation is observed at high temperature and concentration. As the magnetic parameter and magnetic field are inversely proportional according to an induced magnetic field, it is noticed that their magnetic field declines for higher values of magnetic Prandtl number & magnetic parameter. This work has dynamic prominence in the field of medicine and engineering, which develops interest among young researchers.

Heat transfer through a higher grade Forchheimer porous CuO–H2O-nano-medium confined between non-isothermal moving plates

In this study, the aim is to analyze numerically heat transfer through a higher grade Forchheimer porous CuO–H2O-nano-medium in an unsteady magneto-hydrodynamic (MHD) porous flow. The nano-medium is confined between two non-isothermal moving infinite parallel plates. The flow governing equations are developed through variational calculus approach and are resulted in partial differential equations. The temperature of both the plates are taken to be variable. The governing flow PDEs along with the prescribed boundary conditions are solved using finite difference approach for time discretization and finite element approach for discretizing the spatial coordinate. The algorithm used is described here in detail for the numerical simulations and calculations of results. The proposed algorithm is implemented through MATLAB and simulations are performed for parameters of interest which includes: Nusselt number, skin friction coefficients, Forchheimer constant, volume fraction, Prandtl number, Grashhoff number, Hartmann number, and convection and porosity parameters. Effective implementation of the proposed algorithm is demonstrated through plots of time profiles of non-dimensionalized thermodynamic velocity and temperature against these parameters. It is observed that the larger the porosity of the nanomedium leads to the larger skin friction at both the plates. The plate's temperature gets increased with the increase in the Forchhiemer number. However, the hydrodynamic velocities get smaller as the porosity gets elevated. Forchheimer constant and skin friction coefficients are related with direct proportionality. Whereas the skin friction coefficient is observed behaving monotone in relation to the Hartman constant. The Nusselt number at both the plates get increase in its value as the nanoparticles concentration increases. By increasing the velocity ratio between the two moving plates shows opposite trend. However, the Nusselt number decreases if the porosity of the nano-fluidic medium is increased. It is pertinent to mention that the present modeling approach can be used to analyze the Forchheimer medium flows involving catalytic converters and gas turbine dynamics.