MHD Effects Research Articles

Numerical simulation of 3D Darcy–Forchheimer fluid flow with the energy and mass transfer over an irregular permeable surface

The Jeffrey fluid model is capable of accurately characterizing the stress relaxation behavior of non-Newtonian fluids, which a normal viscous fluid model is unable to perform. The primary objective of this paper is to provide a comprehensive investigation into the effects of MHD and thermal radiation on the 3D Jeffery fluid flow over a permeable irregular stretching surface. The consequences of the Darcy effect, variable thickness and chemical reaction are also considered. The phenomena have been modeled as a nonlinear system of PDEs. Using similarity substitution, the modeled equations are reduced to a dimensionless system of ODEs. The parametric continuation method (PCM) is used to determine the numerical solution to the obtained sets of nonlinear differential equations. The impact of physical parameters on temperature, velocity and mass profiles are presented through Figures and Tables. It has been noticed that the energy profile magnifies with the increment of porosity term, thermal radiation and heat source term, while diminishing with the flourishing upshot of power index and Deborah number. Furthermore, the porosity term and wall thickness parameter enhance the skin friction.

Existence of multiple solutions for magnetohydrodynamic flows of second-grade and Walter’s B fluids due continuously contracting flat sheet with partial slip

In the present investigation, an attempt is performed to analyse the existence of multiple exact solutions for magnetohydrodynamic flows of second-grade and Walter’s B fluids due continuously contracting flat sheet with partial slip condition at the boundary. After transforming basic governing equations by suitable similarity transformations, single and double closed-form exact solutions of the flow are achieved on certain restrictions on flow variables of two aforesaid fluids. The impacts of magnetic field and partial slip on existence and non-existence of solutions are revealed. The changes of flow surface drag and velocity with various involved parametric values are also explored. For both viscoelastic type fluids, i.e., second-grade and Walter’s B fluids, double solutions exist for certain flow conditions. In second-grade case, if viscoelastic parameter exceeds a definite value, then double similarity solutions are achieved for any type of flow, i.e., slip flow or no-slip flow. For Walter’s B fluid similar results are obtained with unique similarity slip flow solution if magnitude of viscoelastic parameter exceeds certain fixed value. Importantly, the magnetic field and its MHD effect stabilize the uncertainty situation in existence of similarity solution for both fluids and produce unique solution for a suitable choice.

Heat-mass transfer of MHD second grade fluid flow with exponential heating, chemical reaction and porosity by using fractional Caputo-Fabrizio derivatives

This work studies the analysis of heat mass transfer of generalized second grade fluid. The problem is modelled using Caputo-Fabrizio fractional derivative approach. The effects of MHD, chemical reaction, heat source and porous media are also included. The infinite vertical plate is subjected to the phenomenon of exponential heating. The governing equations along with their corresponding initial and boundary conditions are transformed into non-dimensional form. The system of governing equations has been solved through Laplace transform. Plots are prepared for several physical parameters of interested and discussed in detail. In limiting sense, the published results are recovered analytically and a comparison is made which shows an excellent agreement.

Linear Temporal Stability Analysis of Dual Solutions for a Ti-Alloy Nanofluid with Inclined MHD and Joule Effects: Flow Separation

The impacts of tilted magnetic field and Joule heating on a Ti-alloy nanofluid towards an exponentially permeable stretching/shrinking surface have been looked into in this article. The Tiwari and Das model is adopted for the nanofluid where water is taken as the base fluid and Ti-alloy as the nanoparticles. The dual solutions of the resultant non-dimensional flow equations are evaluated using Shooting and 4th order Runge-Kutta methods and then linear temporal stability analysis is conducted to verify its stability through the smallest eigenvalue approach. The graphical representation of the results for the Ti-alloy/water nanofluid is presented to illustrate interesting features and its stability in the presence of physically effective parameters like inclined magnetic, Joule, volume fraction, and suction parameters. Outcomes of the numerical findings indicate that the dual/multiple solutions are possible only within the limited range of inclined magnetic and suction parameters. Through eigenvalue patterns, it is noticed that the 1st solution is realistic and stable while the 2nd solution is unreliable for each combination. In addition, the streamlines are also displayed to visualize the flow patterns of the Ti-alloy nanofluid. Also, the flow separation point is found in between the shrinking and stretching regions. Finally, the delay of boundary layer separation is pointed out with the enhancing values of volume fraction of Ti-alloy nanoparticles and magnetic parameter in the presence of suction. This kind of analysis performs a very crucial role in the medical sector, aerodynamics and space sciences.

Investigation of MHD effects on micropolar–Newtonian fluid flow through composite porous channel

Investigation of MHD effects on micropolar–Newtonian fluid flow through composite porous channel

Effect of MHD and viscosity variation on the couplestress squeeze film between curved circular plate and a flat porous plate

A theoretical study of MHD with viscosity variation on the squeeze film attributes of a curved circular plate and a flat porous plate using couple stress fluid is examined in this paper. The Reynolds equation in modified is inferred and same is solved to get the expression for film pressure, load supporting capacity and response time in non-dimensional form. As per the computed results, the squeeze film attributes are improved by using a non-Newtonian fluid as a lubricant in association with a magnetic effect. Also, the impact of viscosity variation enhances the squeeze film attributes in comparison with constant viscosity whereas the permeability factor declines the pressure, load supporting capacity and response time as compared to non-porous case.

Parametric dependencies of resonant layer responses across linear, two-fluid, drift-MHD regimes

Non-axisymmetric magnetic fields arising in a tokamak either by external or internal perturbations can induce complex non-ideal MHD responses in their resonant surfaces while remaining ideally evolved elsewhere. This layer response can be characterized in a linear regime by a single parameter called the inner-layer Δ, which enables outer-layer matching and the prediction of torque balance to non-linear island regimes. Here, we follow strictly one of the most comprehensive analytic treatments including two-fluid and drift MHD effects and keep the fidelity of the formulation by incorporating the numerical method based on the Riccati transformation when quantifying the inner-layer Δ. The proposed scheme reproduces not only the predicted responses in essentially all asymptotic regimes but also with continuous transitions as well as improved accuracies. In particular, the Δ variations across the inertial regimes with viscous or semi-collisional effects have been further resolved, in comparison with additional analytic solutions. The results imply greater shielding of the electromagnetic torque at the layer than what would be expected by earlier work when the viscous or semi-collisional effects can compete against the inertial effects, and also due to the intermediate regulation by kinetic Alfvén wave resonances as rotation slows down. These are important features that can alter the non-axisymmetric plasma responses including the field penetration by external fields or island seeding process in rotating tokamak plasmas.

Heat transfer analysis of hybrid nano-fluid through porous medium


 
 
 The main focus of this paper is to use water based hybrid nanofluid in place of ordinary fluid in porous medium to improve thermal properties. This paper deals with the effect of MHD and chemical reaction on a hybrid nanofluid through porous medium with suction/injection. We also studied the effects of MHD, heat source, suction/injection and chemical reaction influences on a hybrid nanofluid. Two types of nano particles namely copper (Cu) and Aluminum oxide (Al2O3) are suspended in base fluid (water) to form the hybrid nanofluid. Similarity transformations are used to change ordinary differential equations to partial equations, and then solved solved by perturbation method. Numerical investigation is carried out to test Skin friction, heat and mass transfer coefficient for different geometrical parameters.
 
 

Neuro-Computing for Hall Current and MHD Effects on the Flow of Micro-Polar Nano-Fluid Between Two Parallel Rotating Plates.

The present works focus on the effects of electric and magnetic fields on the flow of micro-polar nano-fluid between two parallel plates with rotation under the impact of Hall current (EMMN-PPRH) has considered by using Artificial Neural Networks with the scheme of Levenberg–Marquardt backpropagation (ANN-SLMB). The nonlinear PDEs are transformed into nonlinear ODEs by employing similarity variables. By varying different parameters such as coupling parameter, electric parameter, rotation parameter, viscosity parameter, Prandtl number and the Brownian motion parameter, a dataset for recommended ANN-SLMB is produced for numerous scenarios through utilizing homotopy analysis method (HAM). The ANN-SLMB training, testing and validation technique have been used to analyze the approximate solution of individual cases, and the recommended model has matched for confirmation. After that, regression analysis, MSE, and histogram investigations were utilized to validate the proposed ANN-SLMB. The recommended technique is distinguished nearest of the suggested and reference findings, with an accuracy level ranging from 10−09 to 10−11.

Effect of Thermal Radiation and Double-Diffusion Convective Peristaltic Flow of a Magneto-Jeffrey Nanofluid through a Flexible Channel

The noteworthiness of double-diffusive convection with magneto-Jeffrey nanofluid on a peristaltic motion under the effect of MHD and porous medium through a flexible channel with the permeable wall has been theoretically examined. A non-linearized Rosseland approximation is utilized to show the thermal radiation effect. The governing equations are converted to standard non-linear partial differential equations by using suitable non-dimensional parameters. Solutions of emerging equations are obtained by using the multi-step differential transformation method (Ms-DTM). The differential transformation method (DTM) can be applied directly to nonlinear differential equations without requiring linearization and discretization; therefore, it is not affected by errors associated with discretization. The role of influential factors on concentration, temperature, volume fraction, and velocity are determined using graphs. A significant outcome of the present article is that the presence of double-diffusive convection can change the nature of convection in the system. The present results have a wide biological applicability, including for biomicrofluidic devices that regulate the fluid flow through a flexible endoscope and other medical pumping systems.

An Effect of MHD on Non-Newtonian Fluid Flow over a Porous Stretching/Shrinking Sheet with Heat Transfer

The current article explains the 3-D MHD fluid flow under the impact of a magnetic field with an inclined angle. The porous sheet is embedded in the flow of a fluid to yield the better results of the problem. The governing PDEs are mapped using various transformations to convert in the form of ODEs. The yielded ODEs momentum equation is examined analytically to derive the mass transpiration and then it is used in the energy equation and solved exactly by using various controlling parameters. In the case of multiple solutions, the closed-form exact solutions of highly non-linear differential equations of the flow are presented as viscoelastic fluid, which is classified as two classes, namely the second order liquid and Walters’ liquid B fluid. The results can be obtained by using graphical arrangements. The current work is utilized in many real-life applications, such as automotive cooling systems, microelectronics, heat exchangers, and so on. At the end of the analysis, we concluded that velocity and mass transpiration was more for Chandrasekhar’s number for both the stretching and shrinking case.

Comparison study of vertical and horizontal elastic wall on vented square enclosure filled by nanofluid and hexagonal shape with MHD effect

Comparison study of vertical and horizontal elastic wall on vented square enclosure filled by nanofluid and hexagonal shape with MHD effect

Significance of hybrid nanoparticles, Lorentz and Coriolis forces on the dynamics of water based flow

This article addresses a comparative study with MHD effect on the rotational flux of hybrid nano liquid (Al2O3 -Cu/ water) and nano liquid (Al2O3/ water) over the linearly extending surface. Arrhenius activation energy is analyzed along with the chemical species diffusion. The three-dimensional leading equations (PDEs) for momentum, mass, concentration, and temperature are converted into ODEs by employing appropriate similarity conversion. Runge Kutta scheme is implemented and listed in MATLAB to acquire the non-linear differentiated problem's solution numerically. This study aims to explain the detailed examination of repercussions of parameters on velocity, concentration of nano particles and heat via graphical and numerical results. Both velocities (primary and secondary) decreased against the growing rotation value, but temperature distribution and concentration of nano particles are higher for hybrid-phase (Al2O3 - Cu/ water). It is determined that rising inputs of parameters like rotation, porosity factor, activation energy, magnetic effect and Forchheimer number made crucial enhancement in temperature. At linear extending surface, the variational patterns of Nusselt number and skin friction are conducted numerically. Al2O3 - Cu nano particles proved to be a better heat transformer as compared to Al2O3 nano particle.

Rheology of magneto-micropolar nanoliquid toward radiative exponential surface subjected to Brownian motion, thermal radiation, thermophoresis and viscous dissipation

This article is concerned with the simultaneous effects of MHD and radiation on the boundary layer flow of micropolar nanofluid over a stretching sheet. The stretching velocity is assumed to vary exponentially. The considered Buongiorno nanofluid model encompasses Brownian movement and thermophoresis. Heat transfer is studied under thermal radiation and dissipation aspects. Porous medium term is included to capture Darcy’s effects. The nonlinear partial differential equations and selected boundary conditions are transformed first into the dimensionless form using transformations, then the resulting system is solved analytically using the homotopy analysis method (HAM). The importance of physical variables is elaborated through pictorial representations. It is noticed that consideration of radiation aspect improves the fluid temperature.

A review on ferrofluids with the effect of MHD and entropy generation due to convective heat transfer

A review on ferrofluids with the effect of MHD and entropy generation due to convective heat transfer

Numerical Study of Marangoni Convection Flow of GO-Nanofluid with H2O–EG Hybrid Base Fluid with Non-Linear Thermal Radiation

Thermodynamic studies of hybrid colloidal fluids are now of interest. Biomedical science, drug delivery system, electronic chips, paint industries and mechanical engineering are some key applications fields. Hence the current investigation is carried out for Graphene Oxide (GO) nanofluids flow with Marangoni convection over a stretching surface. This investigation is studied under effect of thermal radiation and MHD. The hybrid base fluid is considered with 50-50 percent composition of Water–Ethylene Glycol (H2O–EG). For the numerical simulation of the flow with fourth ordered Runge-Kutta method suitable similarity solutions used. Numerical solutions with graphical representation are presented. From the reported analysis, it is examined that Graphene Oxide/H2O–EG has better heat transport characteristics and is therefore reliable for industrial and technological purposes. With increased radiation and temperature ratio parameters, a decrement in temperature curve is noticed for both nanofluids. For enhancing values of volume friction parameter a decreased velocity curve is noted and increment is noted for temperature profiles for both nanofluids.

Three-dimensional MHD flow in moderate change ratio orifice

In fusion reactor blanket design, liquid metals are attractive working fluids since it is possible to combine in a single fluid the functions of coolant, tritium carrier and breeder. These electrically conductive fluids flow in the presence of a strong magnetic field, inducing the appearance of Lorentz forces and magnetohydrodynamic MHD effects. Increased pressure loss, particularly in complex geometry elements, is a critical point for blanket design. The MHD flow through an orifice plate made by electroconductive walls (c = 0.01 ÷ 0.1) has been analysed in this paper using ANSYS CFX in the range Re = 108, and Ha = 0 ÷ 300. A wide recirculation region is detected after the flow exits the orifice, with potentially harmful consequences for efficient tritium removal. Large pressure loss occurs in the orifice due to conductive wall and non-negligible axial length. The 3D pressure drop term is characterized through a local resistance coefficient (k) that is found to be k ≈ 0.205 for well conducting walls (c = 0.1) and k ≈ 0.063 for poorly conducting ones (c = 0.01).

Unsteady MHD Flow for Fractional Casson Channel Fluid in a Porous Medium: An Application of the Caputo-Fabrizio Time-Fractional Derivative

Theoretically, this work describes the exact solutions of fractional Casson fluid through a channel under the effect of MHD and porous medium. The unsteady fluid motion of the bottom plate, which is confined by parallel but perpendicular sidewalls, supports the flow. By introducing the dimensionless parameters and variables, the momentum equation, as well as the initial and boundary conditions, has been transformed to a dimensionless form. A mix of Laplace and Fourier transformations is used to get the exact solution for the momentum equation. The constitutive equations for Caputo-Fabrizio’s time-fractional derivative are also incorporated for recovering the exact solutions of the flow problem under consideration. After recovering the exact solutions for flow characteristics, three different cases at the surface of the bottom plate are discussed, by addressing the limiting cases under the influence of the side walls. Moreover, these solutions are captured graphically, and the effects of the Reynolds number Re , fractional parameter α , effective permeability K eff , and dimensionless parameter for Casson fluid β on the fluid’s motion are observed.

Free convection flow of second grade dusty fluid between two parallel plates using Fick\u2019s and Fourier\u2019s laws: a fractional model

The paper aims to investigate the channel flow of second grade visco-elastic fluid generated due to an oscillating wall. The effect of heat and mass transfer has been taken into account. The phenomenon has been modelled in terms of PDEs. The constitutive equations are fractionalized by using the definition of the Caputo fractional operator with Fick’s and Fourier’s Laws. The system of fractional PDEs is non-dimensionalized by using appropriate dimensionless variables. The closed-form solutions of thermal and concentration boundary layers are obtained by using the Laplace and finite Fourier-Sine transforms, while the momentum equation is solved by a numerical approach by Zakian using textit{PYTHON}. Furthermore, the parametric influence of various embedded physical parameters on momentum, temperature, and concentration distributions is depicted through various graphs. It is observed that the fractional approach is more convenient and realistic as compared to the classical approach. It is worth noting that the increasing values of M, Sc and Re retard the boundary layer profile. For instance, this behaviour of M is significant where boundary control is necessary. That is, in the case of resonance, the physical solution may be obtained by adding the effect of MHD. The Reynolds number is useful in characterising the transport properties of a fluid or a particle travelling through a fluid. The Reynolds number is one of the main controlling parameters in all viscous flow. It determines whether the fluid flow is laminar or turbulent. The evolution of the rate of heat, mass transfer, and skin friction on the left plate with various physical parameters are presented in tables. These quantities are of high interest for engineers. Keeping in mind the effect of various parameters on these engineering quantities, they make their feasibility reports.

Effect of MHD on Unsteady Oscillatory Couette Flow Through Porous Media

This paper describes the effects of a magnetic field on unsteady free convection oscillatory systems. When temperature and species concentration fluctuate with time around a non-zero constant, “Couette flow” across a porous medium occurs. The system of non-linear ODEs that governs the flow is solved analytically using the perturbation approach because the amplitude of fluctuations is very tiny. Mean flow and transient velocity, transient concentration, transient temperature, heat transfer, mean skin friction and phase and amplitude of skin friction. All have approximate solutions. The influence of different parameters on flow characteristics has been specified and discussed.