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AbstractThe intent of this study is to demonstrate an approach for augmenting heat transfer through porous media subjected to nonuniform heating during the magnetohydrodynamic flow of a hybrid nanofluid of Cu–Al2O3/water. The efficacy of such a heating technique is examined utilizing a classical flow geometry consisting of a square cavity. The heating is made at the bottom following a half-sinusoidal function of different frequencies, along with the presence of a uniform magnetic field. The thermal conditions of the cavity, particularly at the bottom wall, drive thermo-hydrodynamics and associated heat transfer. Furthermore, the addition of different types of nanoparticles to the base liquid in order to boost the thermal performance of conventional fluids and mono-nanofluids is a current technique. The coupled nonlinear governing equations are solved numerically in dimensionless forms adapting the finite volume approach, the Brinkman–Forchheimer–Darcy model, local thermal equilibrium and single-phase model. The study is conducted for wide ranges of parametric impacts to analyze global heat transfer performance. The results of this study reveal that the multi-frequency spatial heating during hybrid nanofluid flow can be utilized as a powerful means to improve the thermal performance of a system operating under different ranges of parameters, even with the presence of porous media and magnetic fields. In addition to different heating frequencies, the variations in amplitude (I) and superposed uniform temperature ( θos ) to half-sinusoidal heating are also examined thoughtfully in the analysis for different concentrations of Cu–Al2O3 nanoparticles. Compared to the base liquid, the hybrid nanofluid can contribute toward higher heat transfer.Graphic abstract

This study examines the effects of a laminar, incompressible, two-dimensional magnetohydrodynamic (MHD) flow subjected to a magnetic field between two orthogonally moving porous plates. By applying a similarity transformation, the governing equations are reduced to a nonlinear ordinary differential equation. We have derived an analytical solution using the generalized Riccati equation mapping method. This work investigates the effect of wall growth ratio on soliton solutions of velocity profiles in an MHD flow between rotating porous discs using the generalized Riccati equation mapping method.

This study proposes Chebyshev wavelet collocation method for partial differential equation and applies to solve magnetohydrodynamic (MHD) flow equations in a rectangular duct in the presence of transverse external oblique magnetic field. Approximate solutions of velocity and induced magnetic field are obtained for steady‐state, fully developed, incompressible flow for a conducting fluid inside the duct. Numerical results of the MHD flow problem show that the accuracy of proposed method is quite good even in the case of a small number of grid points. The results for velocity and induced magnetic field are visualized in terms of graphics for values of Hartmann number Ha ≤ 1000.

This article studies the Soret and Dufour effects on the magnetohydrodynamic (MHD) flow of the Casson fluid over a stretched surface. The relevant equations are first derived, and the series solution is constructed by the homotopic procedure. The results for velocities, temperature, and concentration fields are displayed and discussed. Numerical values of the skin friction coefficient, the Nusselt number, and the Sherwood number for different values of physical parameters are constructed and analyzed. The convergence of the series solutions is examined.

The analysis of mass and heat transfer in magnetohydrodynamic (MHD) flows has significant applications in heat exchangers, cooling nuclear reactors, designing energy systems and casting and injection processes of different types of fluids. On the other hand, extraction of crude oil, the flow of human or animal blood, as well as other polymer fluids or liquid crystals are just some examples of micropolar fluid flows. Due to the broad application spectrum of the theory of micropolar fluid flows, and the significance the impact the external magnetic field has on the flow of these fluids, this paper considers the stationary flow of a micropolar fluid between two plates under the influence of an external magnetic field which is perpendicular to the direction of the flow. Stationary plates are maintained at constant and different temperatures, while the whole problem is considered in the non-inductive approximation. The equation system used to define the physical problem under consideration is reduced to the system of differential equations that have been solved analytically and the solutions of which are of general nature. In addition to the solutions for velocity, microrotation and temperature, the paper gives solutions for shear stress at plates, the Nusselt number and flow rate. The provided solutions have been applied in order to reach some general conclusions about the influence of the magnetic field and physical characteristics of a micropolar fluid and the characteristics of porous media on the nature of micropolar fluid flows in porous media by means of chart analysis. General conclusions, obtained in the result analysis in this paper, give us the opportunity to understand the flows of micropolar fluids and highlight their significance.

This study examines a mathematical model to represent the magnetohydrodynamic flow and heat transfer of Bingham fluids. The model is subject to a magnetic field’s influence and incorporates the modified energy equation derived from Fourier’s law. For numerical computation, we utilize the spectral collocation method in conjunction with the L1 algorithm to address this model. To minimize computational expenses, the sum-of-exponential technology is applied to efficiently solve the time-fractional coupled model. A specific example is provided to demonstrate the numerical method’s stability and the fast method’s efficiency. The results indicate that the numerical method converges with an accuracy of O(τ+N−r), and the fast method is highly effective in reducing computation times. Moreover, the parameters’ impacts on velocity and temperature are presented and discussed graphically. It is evident that as the Hall parameter increases, the peak velocity increases and the amplitude of temperature fluctuations gradually increases, although the peak temperature decreases. The Brinkman number has a significant impact on the heat transfer rate. Meanwhile, as the Hartmann number increases, the inhibitory effect of the magnetic field on the flow is amplified.

This study investigated the three-dimensional magnetohydrodynamic flow and heat transfer of the ternary nanofluid (Cu–Al₂O₃–TiO₂/water) between two coaxial rotating and stretching disks embedded in a porous medium. The model incorporated magnetic field, viscous dissipation, Forchheimer drag, thermal relaxation, disk stretching, and slip boundary conditions to capture realistic flow and thermal behavior. The governing equations are transformed into nonlinear ordinary differential equations via similarity transformations. The semi-analytical solution is obtained using the Homotopy Analysis Method (HAM). COMSOL Multiphysics (FEM) is employed to simulate the full 3D field by validating the analytical result. A parametric study revealed that the ternary nanofluid exhibited superior momentum and heat transfer compared to hybrid and simple nanofluids. Magnetic field and porous drag suppressed velocities but enhanced thermal accumulation, whereas disk rotation and stretching amplified both velocity and Nusselt number. Slip parameters reduce skin friction and heat transfer, while the Eckert number increases flow resistance and temperature. Excellent agreement between HAM and COMSOL confirmed the reliability of the solutions. The findings provide valuable guidelines for enhanced thermal management in industrial and electronic systems, and the study presented a novel analysis of ternary nanofluid behavior in complex rotating and stretching disk geometries.

In this article, some local and parallel finite element algorithms are proposed and investigated for the magnetohydrodynamic flows with low electromagnetic Reynolds number. For a solution to this problem, it comprises of two main components, the low-frequency components and the high-frequency components. Motivated by this, we obtain the low-frequency components globally via some relatively coarse grid and catch the high-frequency components locally using a fine grid by some local and parallel procedures. Some local a priori estimates that are crucial for our theoretical analysis are derived. The optimal error estimates are rigorously derived and some numerical tests are reported to support our theoretical findings.

This article is concerned with the study of free convective unsteady magnetohydrodynamic flow of the incompressible Oldroyd-B fluid along with chemical reaction. The fluid flows on a vertical plate that is impulsively brought in motion in the presence of a constant magnetic field which is applied transversely on the fluid. The structure has been modeled in the form of governing differential equations, which are then nondimensionalized and solved using a numerical technique, that is, Crank–Nicolson’s scheme to obtain solutions for velocity field, temperature distribution, and concentration profile. These solutions satisfy the governing equations as well as all initial and boundary conditions. The obtained solutions are new, and previous literature lacks such derivations. Some previous solutions can be recovered as limiting cases of our general solutions. The effects of thermophysical parameters, such as Reynolds number, Prandtl number, thermal Grashof number, modified Grashof number, Darcy number, Schmidt number, dissipation function, magnetic field, radiation–conduction, chemical reaction parameter, relaxation and retardation times on the velocity field, temperature, and concentration of fluid, are also examined and discussed graphically.

Magnetohydrodynamic (MHD) flow plays a crucial role in various applications, ranging from nuclear fusion devices to MHD pumps. The mathematical modeling of such flows involves convection–diffusion-type equations, with fluid velocity governed by the Navier–Stokes equations and the magnetic field determined by Maxwell’s equations through Ohm’s law. Due to the complexity of these models, most studies on steady and unsteady MHD equations rely on numerical methods, as theoretical solutions are limited to specific cases. In this research, we propose a damped-wave-type mathematical model to describe fluid flow within a channel, taking into account both the velocity and magnetic field components. The model is solved numerically using the finite difference method for time discretization and the finite element method for spatial discretization. Numerical results are displayed graphically for different values of Hartmann numbers, and a detailed analysis and discussion of the solutions are provided.