جستجوی مقالات مرتبط با کلیدواژه « MHD » در نشریات گروه « مکانیک »

This article delves into the interpretation of the Lorentz force's impact when employing the Carreau hybrid nanofluid model with infinite shear rate viscosity over a stretching sheet, which incorporates porous medium. This model is highly effective in elucidating various non-Newtonian fluid behaviors, encompassing shear thinning and thickening properties. The governing equations consist of coupled nonlinear PDEs, which are transformed into a set of coupled nonlinear ODEs using similarity transformations. These equations are then numerically solved using a MATLAB built-in solver (bvp4c). Different characteristics of the considered flow of various parameters, such as the magnetic parameter, porous media parameter, Weissenberg number, stretching parameter, ratio parameter, coefficients space, and heat source/sinks, on temperature and velocity profiles, which are presented graphically. Additionally, the impacts of these parameters on the skin-friction coefficient and Nusselt number are tabulated. The Key findings suggest that, the higher values of the porous media parameter, magnetic parameter, Weissenberg number, and stretching parameter led to a decrease in velocity by 67.12% and 75.49% on average. Moreover, the velocity profile, Nusselt number, and skin friction coefficient are higher for the Al2O3/KO-based nanofluid compared to the Al2O3+MoS2/KO-based hybrid nanofluid. Also, the boundary layer of the hybrid nanofluid is observed to be hotter than that of the single nanoparticle nanofluid.

In this paper, we propose a new technique for solving the magnetic hydrodynamic boundary layer equations after converting them to a nonlinear ordinary differential equation using the appropriate similarity transformation. This technique is based on a combination of the q-homotopy analysis method, the Laplace transform, and the Pade´ approximation, named (q-HALPM). To ensure the method's efficiency, we compared the results of q-HALPM with the ones obtained by methods (DTM-Pade´) and M-HPM . Additionally, the effect of the magnetic parameter on the velocity and heat transfer was studied. The results confirm that the new method has high accuracy and efficiency in finding the approximate analytical solution for the current problem. Moreover, the graphs of the new solutions show the validity and usefulness of the proposed method.

An analysis is carried out on the natural or free convective magnetohydrodynamic flow of a non-Newtonian Jeffrey fluid with a Hall current, heat source, and variable suction near vertical plate.Using a flexible, widely validated variable finite element method, the governing nonlinear partial differential equations be transformed into linear partial differential equations using similarity variables, and this equations along with the associated boundary conditions be then solved numerically.The fluctuation of important parameters in the thermal and hydrodynamic boundary layers be thoroughly examined, and the findings are displayed visually. Additionally, a comparison study is offered to reduce verification and arrive at a excellent consensus. This model is beneficial for geothermal reservoirs, subterranean power transmission, MHD pumps, accelerators, and flow metres, as well as industrial heat management, geological flows within mud cover, etc.

Nanofluids find numerous applications in thermal engineering and industrial processes due to their effective thermal conductivity property compared to regular fluids. A nanofluid consists of containing nanometer-sized particles, called nanoparticles of metals, oxides, carbides, or carbon nanotubes etc. with water, ethylene glycol, and oil etc. serve as base fluids. The present study takes care of effects of Brownian motion and thermophoresis on unsteady Casson fluid flow, heat and mass transfer over a stretching sheet embedded in a porous medium. Moreover, the flow phenomena are subjected to heat source, thermal radiation, viscous dissipation, Joule heating and are associated with the diffusion of chemically reactive nanoparticles to base fluid. These two thermo mechanical aspects draw a little attention of the researchers as reported in literature. The governing equations of flow model admit similarity solution and are reduce to non-linear ordinary differential equations (ODEs) applying suitable similarity transformation and are solved numerically using Runge-Kutta-Fehlberg method with MATLAB code. The interesting outcomes are recorded as follows: The formation of inverted boundary layer, the consequence of flow reversal, is due to overpowering of shearing effect of the rigid bounding surface over the free stream stretching in the absence of suction. The higher magnetic field intensity as well as unsteady flow parameter leads to increasing skin friction coefficient may lead to flow reversal. Hence, regulating these parameters is a suggesting measure. The low Brownian motion in conjunction with high thermophoresis leads to upsurge of thermal energy (hike in temperature profile) near the bounding surface. The presence of nanoparticles considered in the base fluid, deduces the shearing stress at the plate surface is a desired outcome to avoid flow reversal.

In the current study, a comparative analysis of two-dimensional heat transfer by the free convective flow of non-Newtonian Casson and Carreau fluid in electro-conductive polymer on the outside surface of a horizontal circular cylinder under slip and radial magnetic field effects is regarded. The Casson and Carreau fluid model formulation were first developed for the problem of the boundary layer of the horizontal circular cylinder and by using non-similarity transformations, the combined governing partial differential equations are translated into ordinary differential equations. The differential equations obtained are resolved by the Keller Box Method (KBM). The impact of the key parameters, the rate of heat transfer and skin friction is evaluated through graphs and tables. The result reveals that an increase in magnetic number decreases the velocity field of both Casson and Carreau fluid also Casson fluid is higher values when compared to Carreau fluid in variation of magnetic number.

This work reports the heat and mass transfer of the 2- D MHD flow of the Casson and Williamson motions under the impression of non-linear radiation, viscous dissipation, and thermo-diffusion and Dufour impacts. The flow is examined through an extending zone along with inconsistent thickness. The partial differential equations are extremely nonlinear and lessen to ODEs throughout of the appropriate similarity transformation. The system of nonlinear and coupled ODEs is handled applying a numerical approach with shooting procedure. Numerical solutions for momentum and energy descriptions are deliberated through graphs and tabular form for the impacts of magnetic parameter, Soret and Dufour variables, momentum power index variable, Schmidt number, wall thickness variable, without dimensions velocity slip, heat jump and mass jump variable. Outcomes illustrate that the momentum, temperature, and concentration transfer of the laminar boundary layers of equally non-Newtonian liquid motions are non-consistent. A comparison made with the existing literature which shows an good agreement and confidence of the present outcomes. It shows that Casson parameter restricted the skin friction, local heat and mass transfer while l enhanced the skin friction, local heat and mass transfer. Velocity slip constant decreases the skin friction, local heat and mass transfer and a similar observation for thermal slip constant while an opposite phenomena for the solutal slip constant.

In transport as well as manufacturing industries, the two basic aspects are heating and cooling. The use of metal or metallic oxide nanofluids has an effective cooling technique than that of conventional fluids. Therefore, the work is aimed at describing the three-dimensional MHD flow of metal and metallic oxide nanofluids past a stretching/shrinking sheet embedding with a permeable media. Further, thermal properties are enhanced by incorporating heat generation/absorption and radiative heat energy in the heat equation, enhancing the efficiency of temperature profiles. The convective boundary condition for temperature is used, which affects the temperature profile. Suitable similarity transformation is used to transform the governing equations to ordinary differential equations. The approximate analytical solution is obtained for these transformed differential equations employing the Adomian Decomposition Method (ADM). The influences of characterizing parameters are obtained and displayed via graphs, and the computation results of the heat transfer rate for various values of constraints are shown in a table. It is observed that both the momentum and energy profiles decrease with an enhance in the porosity parameter. Also, the fluid temperature decreases with an increasing thermal radiation parameter, but the opposite effect is encountered for the energy generation/absorption parameter.

Theoretical investigation of Ohmic heating (Joule heating) and radiation on MHD Jeffery fluid model with porous material along the tapered channel with peristalsis is the focus of this study. Long wavelength and low-Reynolds number approximations are used in the mathematical modelling. Axial rate, pressure gradient, temperature, and heat transfer coefficient rate expressions are calculated. Plotting diagrams were used to analyse the impact of physical parameters on flow characteristics, which were then addressed in greater depth. It is worth noting that raising the gravitational parameter, Jeffery fluid parameter, Hartmann number and Porosity parameter raises the fluid’s velocity. Also, as the Ohmic heating (Jeffery fluid) parameter and porosity parameter increase, the axial pressure gradient drop;, and the temperature of the fluid rises. The rate of heatt transfer coefficient rises in region with an increase in the Radiation parameter, Heat generator parameter and Jeffery fluid parameter. Mathematica software is employed to seek out numerical results.

In this paper, the influence of the transverse magnetic field is unraveled on the development of steady flow regime for an incompressible fluid in the boundary layer limit of a semi-infinite vertical plate. The sensitivity of real fluids to changes in temperature suggests a variable thermal conductivity modeling approach. Using appropriate similarity variables, solutions to the governing nonlinear partial differential equations are obtained by numerical integration. The approach used here is based on using the shooting method together with the Runge-Kutta-Fehlberg integration scheme. Representative velocity and temperature profiles are presented at various values of the governing parameters. The skin-friction coefficient and the rate of heat transfer are also calculated for different parameter values. Pertinent results are displayed graphically and discussed. It is found that the heat transfer rate improves with an upsurge in a magnetic field but lessens with an elevation in the fluid thermal conductivity.

Theoretical investigation of variable mass diffusivity, thermal conductivity, and viscosity on unsteady squeezed flow of dissipative Casson fluid is presented. Physically, for any effective heat and mass transfer process, a proper account of thermophysical properties in such a system is required to attain the desired production output. The magnetized free convective flow of unsteady Casson fluid encompassing Joule dissipation, radiation, and chemical reactive influence is induced as a result of squeezing property. The governing model assisting the magnetized flow is formulated and transformed via an appropriate similarity transformation. The resulting set of ordinary differential equations is solved numerically using Chebyshev based Collocation Approach (CCA). However, variable viscosity, thermal conductivity, and mass diffusivity effects are seen to diminish the fluid flow velocities, temperature, and concentration respectively along with the lower plate. Heat and mass transfer coefficient, skin friction downsized to an increasing value of variable thermal and mass diffusivity parameters while variable viscosity pronounces the skin friction coefficient. Furthermore, the present analysis is applicable in polymer processing, such as injection molding, extrusion, thermoforming among others.

The purpose of the present analysis is to explore the numerical investigation on the time-dependent 3D magnetohydrodynamic flow of micropolar fluid over a slendering stretchable sheet. The prevailing PDEs are rehabilitated into coupled non-linear ODEs with the aid of appropriate similarity variables and then numerically calculated by applying the 4th RKM incorporate with shooting scheme. The contributions of various interesting variables are shown graphically. Emerging physical parameters on velocity, microrotation, and the surface drag coefficient are portrayed graphically. It is noticed that the microrotation profiles highly influenced by the vortex viscosity parameter and the micro-inertia density parameter. It is also concluded that the microrotation profiles (h2) are promoted by increasing the spin gradient viscosity parameter. Excellent accuracy of the present results is observed with the formerly published as a result of a special case.

In this paper, an analysis of magnetohydrodynamic (MHD) mixed convection over an exponentially stretching surface in the presence of a non-uniform heat source/sink and suction/injection is presented. The governing boundary layer equations are transformed into a set of non-dimensional equations by using a group of non-similar transformations. The resulting highly non-linear coupled partial differential equations are solved by using the implicit finite difference method in combination with the quasilinearization technique. Numerical results for the velocity, temperature and concentration profiles, as well as the skin friction coefficient, wall heat transfer and mass transfer rates are computed and presented graphically for various parameters. The results indicate that the velocity profile reduces, while the temperature profile increases in presence of the effects of magnetic field and suction at the wall. The velocity ratio parameter increases the skin-friction coefficient and the Schmidt number decreases the wall mass transfer rate. The temperature profile increases for the positive values of Eckert number and space as well as temperature dependent heat source/sink parameters, while the opposite behavior is observed for negative values of same parameters.

This paper examines the unsteady magnetohydrodynamic (MHD) mixed convection flow over a sphere combined with variable fluid properties. An implicit finite difference scheme, together with the quasi-linearization, is used to find non-similar solutions for the governing equations. The vanishing skin friction is prevented or at least delayed by enhancing the mixed convection in both the cases of steady and unsteady fluid flow. Both skin friction and heat transfer coefficients are found to be increasing with an increase in time or MHD parameter.

Due to the presence of rheological flow parameters and viscoelastic properties, non-Newtonian fluid structure is intricate and enticing to investigate. The flow has been made by considering variable temperature and radiation effects for the magnetohydrodynamic viscoelastic liquid past a moving vertical plate in a porous state. First order homogeneous chemical reaction, Soret number, variable temperature and concentration have been taken into account. The leading mathematical proclamation is handled analytically by perturbation strategy. The central aspiration of this work is to explore the consequences of sundry parameters on fluid flow, thermal boundary and concentration profiles. Diagram and tabular trends of the profiles are delineated with apropos parameters. Our sketches illustrate that the velocity profile exposes   decelerate scenery with escalating M due to the Lorentz force in the opposite direction of flow. Temperature profile is getting accelerated owing to thermal radiation and concentration distribution is declined by boosting up the chemical reaction and Schmidt number. Diminishing nature of momentum boundary layer with Sc is also portrayed. Furthermore, at the end of this paper the effects of different parameters on skin fricition coefficient and local Nusselt number are investigated.

This study analyses the combined effect of chemical reaction and Soret number on MHD flow of a viscous and incompressible fluid near the exponentially accelerated infinite vertical plate in a rotating system. The fluid under consideration is electrically conducting and the medium is porous. A set of dimensionless governing equations of the model is obtained. As the equations are linear, an exact solution is derived by using Laplace technique. The effects of flow parameters on the concentration, temperature and velocity are discussed through graphs. It is noticed that the components of the velocity in both the directions can be increased by increasing the Soret number; and the velocities can be reduced by increasing the chemical reaction parameter. Tables depict the numerical values of the rate of change of momentum, concentration and temperature. Applications of the study  are considered  in the fields like solar plasma and planetary fluid dynamics systems, rotating MHD generators, etc.

Entropy generation due to viscous incompressible MHD forced convective dissipative fluid flow through a horizontal channel of finite depth in the existence of an inclined magnetic field and heat source effect has been examined. The governing non-linear partial differential equations for momentum, energy and entropy generation are derived and solved by using the analytical method. In addition; the skin friction coefficient and Nusselt number are calculated numerically and their values are presented through the tables for the upper and the bottom wall of the channel. It was concluded that; total entropy generation rate and Bejan number are reduced due to rise in the inclination angle of the magnetic field. Also, an increment in the heat source prop ups the fluid temperature and total entropy generation rate. This study will help to reduce the energy loss due to reversible process and heat dissipation. The results are very useful for chemical and metallurgy industries.

In the present paper, a numerical investigation of transport phenomena is considered in electrically-conducting nanofluid flow within a porous bed utilizing Buongiorno’s transport model and Runge-Kutta-Fehlberg fourth-fifth order method. Induced flow by non-isothermal stretching/shrinking sheet along with magnetic field impact, dissipation effect, and slip conditions at the surface are also included. The numerical results show the existence of two branches of the solution for a selected range of the governing parameters. The physical significance of both branches of solutions is ensured by performing a stability analysis in which a linearized eigenvalue problem is solved. The multiple regression analysis with the help of MATLAB LinearModel.fit package has also been conducted to estimate the dependence of the parameters on Nusselt number.

In this study, effects of numerous physical quantities like dissipation, thermal radiation, and induced magnetic field on magnetohydrodynamic Casson fluid flow through a vertical plate is addressed. The non-dimensional multivariable governing equations are solved numerically by by means of Runge-Kutta method along with shooting technique. The behavior of velocity, temperature and induced magnetic fields for different physical aspects is discussed through graphical illustrations. The influence of physical constants like Casson fluid (β), Magnetic parameter Μ, Soret number Sc, Prandtl number Pr, Magnetic Prandtl number etc., on induced magnetic field, temperature and velocity is analyzed. Interesting observation of this study is that the effect of velocity distribution obeys the physical nature of well-known Newtonian and all other Non-Newtonian fluids.

This paper deals with a theoretical investigation of heat and mass transfer with thermal radiation analysis on hydromagnetic peristaltic Prandtl fluid model with porous medium through an asymmetric tapered vertical channel under the influence of gravity field. Analytical results are found for the velocity, pressure gradient, pressure rise, frictional force, temperature and concentration. The influence of varied governing parameters is discussed and illustrated diagrammatically through a set of figures. It can be seen that the axial velocity enhances with an increase in gravity parameter. It is observed that the temperature of the fluid reduces within the tapered asymmetric vertical channel by an increase in thermal radiation parameter. Blood flow in concentration profile increases with an increase in thermal radiation parameter. It is worth mentioning that the rate of pumping rises in all the four regions, i.e. retrograde pumping region, peristaltic pumping region, free pumping region and an augmented region with an increase in Prandtl fluid parameter.