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This work presents a vibrational and electronic (vibronic) state-to-state (StS) model for nitrogen plasmas implemented within a multi-physics modular computational framework to study non-equilibrium effects in inductively coupled plasma (ICP) discharges. The vibronic master equations are solved in a tightly coupled fashion with the flow governing equations eliminating the need for invoking any simplifying assumptions when computing the state of the plasma, leading to a high-fidelity physical modeling. The model's computational complexity is reduced via a maximum entropy coarse-graining approach, verified through zero-dimensional isochoric calculations. The coarse-grained StS model is employed to study the plasma discharge in the ICP facility at the von Karman Institute for Fluid Dynamics, Belgium. Results reveal pronounced discrepancies between StS predictions and those obtained based on local thermodynamic equilibrium (LTE) models, which are conventionally used in the simulation of such facilities. The analysis demonstrates a substantial departure of the internal state populations of atoms and molecules from the Boltzmann distribution. This has significant implications for energy coupling dynamics, affecting the discharge morphology. Further analysis reveals a quasi-steady-state population distribution in the plasma core, allowing for the construction of an efficient and 'self-consistent' macroscopic two-temperature (2T) formulation. Non-LTE simulations indicate significant disparities between the StS model and the commonly used Park 2T model, whereas the newly proposed 2T model aligns closely with StS simulations, capturing key features of non-equilibrium plasma formation. In particular, the current study highlights the importance of the vibrational-translational energy transfer term in shaping the plasma core morphology, suggesting a notable sensitivity to heavy-impact vibrational excitations and dissociative processes. [ABSTRACT FROM AUTHOR]

This work analyzed numerically the impacts of viscous dissipation, Joule heating and inclined magnetic field on reactive-diffusion magneto-hydrodynamic radiative mixed convection oscillatory non-Newtonian Casson fluid (CF) fluxing across a slanted semi-infinite vertical plate inserted in a porous medium. The framed dimensional flow controlling partial differential equations were modified to dimensionless partial differential equations by bringing in applicable scaling variables and then numerically solved by imposing the finite difference scheme. The outcomes are established with graphical representations to inspect the flow fields’ performance for diverse flow parameters. At the same time, numerical data of skin friction and heat and mass transferal rates near the surface area are presented in a tabular format. This research study discovered that the viscous dissipation and radiation effects intensify the temperature and velocity fields while heat ingestion has a contrary effect. Both velocity and concentration distributions are diminished by the chemical reaction and Schmidt number while the converse trend was noted with thermo-diffusion effect. The velocity distribution was narrowed by the angled magnetic field, Casson parameter, and magnetic field but the porosity parameter exposed the opposite impact. The influence of the magnetic field and Casson parameters incited to decline the friction. Heat absorption in the flow makes the Nusselt number rise but improving viscous dissipation and radiation effects have pointed to an opposite trend. The chemical reaction parameter increases the Sherwood number but thermo-diffusion decreases it. Further, validation with already published results is accomplished and an excellent agreement is realized. [ABSTRACT FROM AUTHOR]

Bioconvection in hybrid nanofluids refers to the phenomenon where biological microorganisms such as algae or bacteria exhibit collective movement or pattern formation in a suspension containing nanoparticles. This phenomenon has significance in various fields, including biology, nanotechnology, and engineering. The current investigation emphasizes the bioconvective flow of a water (H2O)−ethylene glycol (C2H6O2)-based hybrid nanofluid flow by a curved stretched sheet. Copper (Cu) and silver (Ag) nanoparticles are suspended in the base fluid. The thermal field is analyzed in the presence of heat generation, dissipation, Joule heating, and the impact of thermal radiation. Binary reactions associated with Arrhenius energy are accounted in the modeling of mass concentration. The phenomenon of bioconvection is considered to regulate the random movement of tiny solid particles within the flow. Boundary layer constraints are implemented to eliminate ineffective terms from modeling. The transformation procedure is adopted to obtain the flow governing system of ODEs. The built-in code of Mathematica (NDSolve) is implemented to obtain the graphical and numerical results. The results show that the velocity field decreases with increasing porosity variable and Hartmann number. An opposite impression of the Eckert number and Schmidt variable on the thermal field is noticed. Bioconvection Peclet and Lewis numbers have a direct relationship with motile density. [ABSTRACT FROM AUTHOR]

In this communication, the authors focused on energy loss during the flow of hybrid nanofluid in expanding/contracting channels. The goal is to determine how, in real-world applications, hybrid nanofluids can maximize energy efficiency and reduce entropy production, hence assisting in the development of more effective and sustainable thermal management systems. It is well documented that heat transfer is enhanced due to the presence of nanoparticles in a base fluid and hence decreases energy loss in the system. The second law of thermodynamics defines that heat transfer is not ideal; hence, entropy in a system always rises. Suitable measures can be taken to minimize energy loss. One method is to use a nanofluid, if multiple nanosized particles are used; it is named a hybrid nanofluid. In this communication, a comparative analysis of simple and hybrid nanofluids is provided. A mathematical model outlining the dynamics of the flow is provided. The upper plate acts as a porous plate that is contracting/expanding and through which coolant hybrid nanofluids enter the channel. The lower plate remains stationary and is heated externally. The equations governing the flow are converted into ordinary differential equations by employing the similarity transformation. These ODEs are then solved analytically to get the series solution by using HAM along with the given boundary conditions. The entropy equation is modelled using the Clausius Duhem inequality. Copper and silver nanoparticles are combined with water. The impacts of different dimensionless parameters on stream function, velocity profile, Nusselt number, entropy, and Bejan number are discussed, and their results are shown graphically.

Nanofluids, due to their complex behavior and enhanced thermal properties, are utilized across chemical, biotechnology and thermal engineering disciplines. They are particularly integral to heat transfer processes in heavy machinery and vehicles. This study introduces a novel method for analyzing heat transfer within a tetra nanofluid system through a hybrid analytical and numerical approach. Our research primarily examines the dynamics of a magneto Williamson hybrid tetra nanofluid embedded with motile gyrotactic microorganisms. The study is designed around two scenarios: one investigates the behavior of an Al2O3–Cu–CuO–Cobalt/Engine oil nanofluid under suction conditions, and the other under injection conditions. By employing similarity variables, we transform the original fluid flow equations into nonlinear differential equations to further explore the influence of various physical parameters on the fluid's flow. Such parameters include the nanofluid temperature and velocity as well as the concentration of nanoparticles, and the volume fraction of motile gyrotactic microorganisms. The optimization of the numerical results for skin friction, Nusselt number, Sherwood number and microorganisms concentration is validated through response surface optimization techniques. Additionally, the study utilizes Matlab's bvp4c function to examine the thermal efficiency and characteristics of fluid flow across a spectrum of parameter values. The study investigates two-dimensional boundary layer flow over a stretched sheet in a nanofluid with gyrotactic microorganisms under a magnetic field. Assumptions include no nanoparticle aggregation and negligible induced magnetic field. Key parameters include stretching velocity Uw, mass flux velocity v0, and positive y-direction magnetic field B0. We found that the microorganisms maintain nanoparticle suspension. [ABSTRACT FROM AUTHOR]

This study numerically investigates the characteristics of a non‐Newtonian magnetohydrodynamic flow in a cross‐slot. Numerical simulations are performed using power law, Bird–Carreau and Casson non‐Newtonian fluid models. The flow characteristics and shear viscosity behavior in the flow region are analyzed for different values of magnetic field. Additionally, the dynamic behavior of the bifurcated flow in the cross‐slot is studied in detail, and the computational results are compared with existing models. It is shown that the fluid velocity is reduced in both the inlet and outlet channels of the cross‐slot due to the magnetic field, regardless of the viscosity model. Moreover, it is found that the fluid viscosity increases along the centerline of the inlet channels and decreases in the outlet channels of the cross‐slot for all non‐Newtonian fluid models tested here. Furthermore, this study shows that the flow properties of the non‐Newtonian fluids can be controlled by changing the magnetic field strength. The results of this study will be useful for analyzing the flow behavior of blood in a microfluidic cross‐slot and other rheological fluids used in biochemical engineering and industrial processes, where higher mass transfer and mixing efficiency can be achieved by imposing an external magnetic field. Highlights: Simulation of non‐Newtonian magnetohydrodynamic flow in a cross‐slot is conducted.Analysis of the flow and shear viscosity behavior for different Hartman number is performed.Flow properties were successfully controlled with the imposed external magnetic field. [ABSTRACT FROM AUTHOR]

This work signifies insights into diverse phenomena relevant to fluid dynamics, heat transfer, and chemical reactions in advanced materials. This work aims to discuss the mixed convective Casson magneto-hydrodynamics (MHD) hybrid nanofluid flow on a surface which is stretching in an exponential manner. To mechanize the thermal behavior of flow, the Buongiorno model along with dissipative effects has been incorporated in the current problem. Suitable variables have been employed to change the system of leading equations into dimensionless form, and the homotopy analysis approach (HAM) has been employed for the solution of resultant equations. As the outcome of this work, it has been observed that velocity distribution is reduced with escalation in magnetic, mixed convection, porosity, and buoyancy ratio factors. Thermal profiles are escalated with growth in Brownian motion, thermophoresis, magnetic field, and radiation factors as well as Eckert number. A comparative analysis has also been conducted in this work and found an acceptable agreement among previous and current results. [ABSTRACT FROM AUTHOR]

A hydro-dynamic thermal fully developed forced convective heat transfer analysis of magneto-hydrodynamics fluid flow through an annular sector duct is presented in this paper. Two types of thermal boundary conditions i.e., axially uniform heat flux along with peripherally uniform temperature (known as H1-condition) and, axially and peripherally uniform temperature (known as T condition), have been considered to carry out the thermal analysis of fluid. The velocity components along r and θ direction are transformed into algebraic form by using power law discretized scheme, whereas cross-sectional pressure P (r , θ) is estimated with the help of well know technique S I M P L E R. The governing partial differential equations are solved by numerically with the help of M A T L A B code. Furthermore, simulated results have been compared with the existing results of literature to validate the results. From the results, it is noted that hydro-dynamically and thermally impacts relate directly by increasing the Hartman number, (M). It is further reported that the effect of magnetic field becomes insignificant for the higher number of fins, N. The findings of the present analysis will be applicable in various types of thermal systems. [ABSTRACT FROM AUTHOR]

Here, unsteady boundary layer flow under the action of magnetic effect over a moving stagnation surface has been investigated numerically. This study examines non-Newtonian fluid flow with respect to combined effect of magnetic field, movement of surface and time. Governing equations are dimensionless by applying nondimensional quantities. Then system of coupled ordinary differential equations are obtained by appropriate similarly transformations, in terms of the governing parameter including unsteady parameter (k) , magnetic number (M) , power-law index (n) and three-dimensional parameter (α). Thus, the obtained modelled equations are solved numerically by the shooting technique. The problem's parameters are thoroughly discussed and verified physically and graphically. The obtained results validate to literature result. The two relevant flows' velocity profile's numerical results have been examined. [ABSTRACT FROM AUTHOR]

The magneto-hydrodynamics (MHD) double-diffusive mixed convection and heat generation/absorption in a lid-driven inclined wavy enclosure filled with (Fe3O4/ water) ferrofluid is quantitatively investigated in this paper. The present study focuses on improving the efficiency of mass and thermal performance of a system. Both the left and right sidewalls of the cavity are allowed to move with a constant velocity in the upward and downward directions, respectively. The finite difference approach was applied to discretize the subsequent governing equations followed by the Bi-Conjugate Gradient Stabilized (Bi-CGStab) method to solve them. The numerical simulation was performed for a variety of parameters, including the Hartmann number varied as 0 ≤ Ha ≤ 45, the inclination angle of the enclosure varied as 0° ≤ δ ≤ 180°, the buoyancy ratio varied as -2 ≤ N ≤ 2, heat generation or absorption parameter varied as −10 ≤ Qo ≤ 10, Richardson number varied as 0.01 ≤ Ri ≤ 10, and solid volume fraction varied as 0 ≤ ϕ ≤ 0.06. The numerical simulation results were presented in terms of streamlines, isotherms, isoconcentrations, average Nusselt number, and average Sherwood number. The heat and mass transfer rates were found to decrease with the increase in Ha but increase with N, Ri, and Φ. Also, both of them reach their peak values at Ri = 10. In addition, the heat generation parameter enhances both thermal and mass performance as they reach their maximum values at Qo = 10. Increasing the heat generation factor from Qo = 5 to Qo = 10 increases the Nusselt number by 3.5 times. The outcomes of the study have significant importance for modern industrial applications specifically in the discipline of electronic device cooling.

This study explores the influence of Fe3O4 – water nanofluid, magnetic forces, and double-diffusive mixed convection characteristics on a steady-state, two-dimensional, laminar flow within an inclined square cavity containing four heated square blockages. The governing equations are solved using the Finite Volume Method (FVM). In this configuration, the temperature and concentration inside the square blockages are higher than those on the left and right walls, which are moving in opposite directions to each other. The remaining two are adiabatic and impermeable. A wide range of parameters is investigated, including cavity nanoparticle volume fractions (φ = 0.0, 0.02, 0.04, 0.06), inclination angle (γ = 0°, 30°, 60°), Richardson number (Ri = 0.1, 1.0, 10), Hartmann number (Ha = 0, 50, 100), heated block ratio (B = 1/8), Lewis number (Le = 5.0), Prandtl number (Pr = 0.71), and Buoyancy ratio (N = 2.0). The study extensively analyzes temperature, concentration, and streamline contours based on these parameters. Furthermore, the research examines the heat and mass transfer rates on the heated block surfaces by analyzing local and average Nusselt (Nuavg) and Sherwood numbers (Shavg). The results suggest that introducing nanofluid has a more pronounced influence on the flow fields than the temperature and concentration patterns. Both the inclination angle and the Hartmann number have a significant impact on both the flow and temperature patterns. At higher Ri, an increase in φ reduces the Nuavg and Shavg. However, the total Nuavg and Shavg decrease at any Ri and γ in a magnetic field.

The magnetically driven sample experiments which were carried out in an intense pulsed power device were simulated and analyzed by two-dimensional magnetically driven simulation code (MDSC2), and the structure coefficient of magnetically driven sample experiments was studied and analyzed. The numerical results show that MDSC2 can correctly simulate experiments of magnetically driven samples such as tin and magnesium-aluminum alloy. The simulated sample/window interface velocity (or flyer plate/window interface velocity) is basically consistent with the experimental measured one. The structure coefficients of magnetically driven samples are usually different when the magnetically driven sample experiments are different. The structure coefficient of magnetically driven sample experiment is related to the initial conditions such as the sample material and the width of the electrode plate but not to the initial thickness of the sample material. Under the same initial conditions, such as the thickness of the flyer plate, the material of the flyer plate, the material of the sample, the initial gap between the cathode and the anode, the wider the electrode plate, the larger the structure coefficient of the magnetic drive sample experiment. MDSC2 can correctly simulate the magnetically driven sample experiments, which makes MDSC2 an important tool for the study of magnetically driven sample experiments. [ABSTRACT FROM AUTHOR]

Nanotechnology is well-known for its versatile and general thermal transport disciplines, which are used in semiconductors, spacecraft, bioengineering, functional electronics, and biosensors. As a result, process optimization has attracted the interest of scientists and technologists. The main aim of the current analysis is to explore the enhancement of energy/heat transfer via the dispersion of cylindrical-shaped nanoparticles of alumina and copper in ethylene glycol as a base fluid using a non-Newtonian Maxwell fluid model. In the current study, the effects of solar radiation, plate suction, and magnetohydrodynamics on a Maxwell hybrid nanofluid are encountered. The flow is induced by linearly stretching a sheet angled at ξ = π / 6 , embedded in a porous space. The proposed problem is converted into a mathematical structure in terms of partial differential equations and then reduced to ordinary differential equations by using appropriate similarity variables. In the similarity solution, all the curves for the velocity field and temperature distribution remain similar, which means that the symmetry between the graphs for the velocity and temperature remains the same. Therefore, there is a strong correlation between similarity variables and symmetry. The obtained model, in terms of ordinary differential equations, is solved using the built-in numerical solver bvp4c. It is concluded that more nanoparticles in a fluid can make it heat up faster, as they are typically better at conducting heat than the fluid itself. This means that heat is transferred more quickly, raising the temperature of the fluid. However, more nanoparticles can also slow the flow speed of the fluid to control the boundary layer thickness. The temperature field is enhanced by increasing the solar radiation parameter, the magnetic field parameter, and the porous medium parameter at an angle of   ξ = π / 6 , which serves the purpose of including radiation and the Lorentz force. The velocity field is decreased by increasing the values of the buoyancy parameter and the suction parameter effects at an angle of   ξ = π / 6 . The current study can be used in the improvement of the thermal efficiency of nanotechnological devices and in renewable energy sources to save energy in the energy sector. The present results are compared with the published ones, and it is concluded that there is excellent agreement between them, which endorses the validity and accuracy of the current study. [ABSTRACT FROM AUTHOR]

The primary goal of this research study is to examine the influence of Brownian motion and thermophoresis diffusion with the impact of thermal radiation and the bioconvection of microorganisms in a symmetrically stretching sheet of non-Newtonian typical Williamson fluid. Structures of the momentum, energy, concentration, and bio-convection equations are interconnected with the imperative partial differential equations (PDEs). Similarity transformations are implemented to translate pertinent complicated partial differential equations into ordinary differential equations (ODEs). The BVP4C approach from the MATLAB assemblage computational methods scheme is extensively impacted by the results of these ODEs. The impact of several physical parameters, including Williamson fluid W e (0.2 ≤ W e ≤ 1.2) , the magnetic field parameter M (0.0 ≤ M ≤ 2.5) , Brownian motion N b (0.0 ≤ N b ≤ 1.0) , thermophoresis diffusion N t (0.1 ≤ N t ≤ 0.9) . In addition, various physical quantities of the skin friction ( R e x C f x ), Nusselt number ( N u x ), Sherwood number ( S h x ), and motile microorganisms ( N n x ) are occupied and demonstrate the visualization of graphs and tabular values. These outcomes are validated with earlier obtained results, displaying excellent synchronicity in the physical parameters. Furthermore, the physical quantities concerning the non-dimensional parameters are anticipated by employing Multiple Linear Regression (MLR) in Machine Learning (ML) as successfully executed a novelty of this study. These innovative techniques can help to advance development and technologies for future researchers. The real-world implications of this research are that bio-remediation, microbial movements in mixed fluids, and cancer prevention therapy are crucial. [ABSTRACT FROM AUTHOR]

This analysis investigates the unsteady MHD free convection flow and heat transfer in an inclined U-shaped cavity filled with Cu-water nanofluid. Both the right and left walls of the cavity and the internal walls of the cavity are supposed to be adiabatic, while the upper horizontal walls of the cavity are kept at a lower temperature. A heat source is located on the bottom horizontal wall with its position that alters the left vertical wall. The dimensionless governing equations are solved using the Successive Under-Relaxation technique. The investigation is achieved by controlling the impact of a set of pertinent parameters, namely; the size and position of the heat element (B = 0.3–0.6, D = 0.3–0.6), Hartman number (Ha = 0–50), nanoparticle volume fraction (ϕ = 0.0–0.07), heat source generation/ absorption (Q = −4.0–2.0), and aspect ratio (AR = 0.2–0.6). The results show that the mean Nu declines with heat source length and Hartmann number, whereas it augments with dimensionless heat source location. Furthermore, the mean Nu rises in parallel with the solid volume fraction of nanoparticles and decreases with aspect ratio. In addition, the increasing of aspect ratio reduces the convection mode compared to conduction heat transfer.

The magnetic outcomes are frequently implemented for assessing fluid specifications around stretching magnetized surfaces and energy producing technology of thermodynamics. Magnetohydrodynamic reactors and magneto-hydrodynamic generators are two primary methods for producing magnetic flux through ionized fluids along a warmed and magnetized stretched surface. The desired outcomes of the current work are to investigate magnetic flux and heat transmission in the presence of convective boundary conditions using an electrically-conducting fluid over a stretchable cylinder. Most of the parameters are considered in the discussion with intensity and variance due to time dependent methodology. The suggested fluctuating dynamic computational framework is formulated for associated forms of coupled model under boundary variables. The appropriate non-dimensional variables are used to transform the complicated mathematical expression into a non-dimensional representation. To make the non-dimensional representation easier to work for efficient statistical calculations, it is reduced further. Later, for a variety of variables, significant computations are performed via the implicit finite difference methodology. The main finding of current communication is to explore the prominent slip effect in temperatures for every Biot number around all positions. From a physical standpoint, the phenomenon was predictable since surface heat flux is employed as sporting source to increase heat transmission in electric-conducting fluids. For every possible angle, the field of magnetism increases with minimal intensity of surface heat flux. Since, magnetizing functions referred to as an insulating layer that diminishes high temperatures across surfaces and fluids.

The numerical modelling of high amperage aluminium electrolysis cells requires to account for a variety of their individual features: electric current and associated magnetic field distribution, ferromagnetic parts effect, the velocity field in the two overlying fluid layers, their interface deformation and wave motion, referred to as MHD instability. The normal electrolytic process is regularly disrupted due to the anode changes and the feeding of alumina (Al2O3) particulate material ensuring the continuity of the electrolytic aluminium production. The proposed modelling technique of alumina dissolution uses Lagrangian tracking for feed material particles of different sizes accounting for their inertia, drag in the turbulent flow, the electrolyte layer shape and the electromagnetic force at the location. The feed material initially forms rafts of frozen electrolyte+alumina, which gradually disperse and dissolve depending on the local flow, turbulent diffusion, and the instantaneous concentration level below saturation until reaching a quasi-steady concentration distribution. The concentration of solution is continuously depleted due to the electrolytic metal production. Modelling is applied to illustrate optimization of the commercial cell performance, while avoiding regions of low concentration responsible for increased fluoride gas release due to the low voltage anode effect. [ABSTRACT FROM AUTHOR]

This article is designed to inspect the thermal effects of an unsteady compressible flow of a viscous fluid through a symmetric channel. Combined effects of convective heat transfer, magnetic field, and radiation are also given special attention in this article. Basic laws of mass, momentum, and energy for compressible flow are employed in the modeling of the current problem. In addition, slip boundary conditions are also implemented in the analysis of the above thermal flow problem. Coupled nonlinear differential equations are solved numerically using explicit finite difference technique. Finally, the influence of different sundry parameters on the axial velocity, flow rate, and heat transfer are visualized through graphs. Time variant behavior of flow rate is calculated. Outcomes of the results reveal that the increment of the flow rate is related to the increase of compressibility parameters. Enhancement in the temperature profiles in the presence of radiation number is also reported. This model is the most general version of peristalsis of compressible flow in view of natural convection and radiation impact with extensive applications in aircraft industry, geophysics, and other industrial situations (cooling of electronic equipment, heat exchangers, and so forth). [ABSTRACT FROM AUTHOR]

The presented article aims to present the flow of blood in microchannels such as veins and arteries via peristaltic flow. The magnetic field is imposed to regulate the flow as laminar. Also, its impacts in terms of Hall current have been considered. The rate of heat transfer is further based on Joule heating and viscous dissipation aspects. Mathematical analysis has been conducted given long wavelength and small Reynolds number. Such preferences are relatable to the medical domain where the magnetic field regulates the flow stream and aids in the melting of blood clots in patients with various heart diseases. The solution for electric potential is calculated analytically while the velocity, temperature, and heat transfer rate are executed directly via the built-in command of Mathematica software. Since the magnetic field acts as an opposing force. Results show that the velocity and temperature are decreasing functions of the magnetic field. However, the temperature is increasing for Weissenberg number.

This paper considers the problem of the uniqueness of the solution to the coefficient inverse problem for the system of equations of magneto-hydrodynamics, the solution to which allows more accurately describing the processes of generating the magnetic field of planets with a magneto-hydrodynamic dynamo. The conditions under which it is possible to determine three components of the magnetic induction vector and the magnetic field diffusion coefficient are determined.

This analysis investigates the unsteady MHD free convection flow and heat transfer in an inclined U-shaped cavity filled with Cu-water nanofluid. Both the right and left walls of the cavity and the internal walls of the cavity are supposed to be adiabatic, while the upper horizontal walls of the cavity are kept at a lower temperature. A heat source is located on the bottom horizontal wall with its position that alters the left vertical wall. The dimensionless governing equations are solved using the Successive Under-Relaxation technique. The investigation is achieved by controlling the impact of a set of pertinent parameters, namely; the size and position of the heat element (B = 0.3–0.6, D = 0.3–0.6), Hartman number (Ha = 0–50), nanoparticle volume fraction (ϕ = 0.0–0.07), heat source generation/ absorption (Q = −4.0–2.0), and aspect ratio (AR = 0.2–0.6). The results show that the mean Nu declines with heat source length and Hartmann number, whereas it augments with dimensionless heat source location. Furthermore, the mean Nu rises in parallel with the solid volume fraction of nanoparticles and decreases with aspect ratio. In addition, the increasing of aspect ratio reduces the convection mode compared to conduction heat transfer. [ABSTRACT FROM AUTHOR]

A novel three-dimensional two-step numerical model was developed and analyzed for a tandem process with a reverse-polarity hot wire. Magneto-hydrodynamic analysis was conducted and the free surface of the molten pool was tracked to investigate the arc and molten pool behaviors of the proposed process, respectively. The results indicated that a change in electromagnetic force by the hot wire reduced arc deflection, which increased the arc velocity in the co-axial direction of electrodes, thereby increasing the arc pressure and arc shear force acting on the molten pool. Consequently, the molten pool in the novel tandem process was wider and deeper than that in the conventional tandem process.

In the present work, we investigate the effects of the magnetic field on expanding hot and dense nuclear matter as an ideal fluid. We consider QGP, in the particular case of a (1 + 2) dimensional longitudinally boost-invariant fluid expansion, in the background of an inhomogeneous magnetic field that is generated by external sources. We assume the magnetic field points in the direction perpendicular to the reaction plane, follows the power-law decay in proper time, and has two components on the transverse plane. To simplify our calculation, we suppose the investigated fluid has azimuthal symmetry, and magneto-hydrodynamic equations are described in a polar coordinate system on the transverse plane of reaction. Our results depict the space-time evolution of the transverse expansion of the fluid in the presence of an inhomogeneous external magnetic field. Moreover, we show when the magnetic field decays in proper time τ with a power-law τn/2(n−2 leads to non-physical results.

In a magnetic field, two-dimensional (2D) mixed convection is investigated within a zigzagged trapezoidal chamber. The lower side of the trapezoidal chamber is irregular, in particular, a zigzagged wall with different zigzag numbers N. The fluid particles move in the room due to the motion of the upper wall, while the porosity-enthalpy approach represents the melting process. The thermal parameters of the fluid are enhanced by what is called a nano-encapsulated phase change material (NEPCM) consisting of polyurethane as the shell and a nonadecane as the core, while water is used as the base fluid. In order to treat the governing equations, the well-known Galerkin finite element method (GFEM) is applied. In addition, the heat transfer (HT) irreversibility and the fluid friction (FF) irreversibility are compared in terms of the average Bejan number. The main results show that the melt band curve behaves parabolically at smaller values of Reynolds number (Re) and larger values of Hartmann number (Ha). Moreover, minimizing the wave number is better in order to obtain a higher heat transfer rate. [ABSTRACT FROM AUTHOR]

In this paper, we present a detailed mathematical model of the unsteady hybrid blood through the curved overlapping stenosed vessels in the presence of the applied external magnetic field. The governing differential equations of this model are derived from the generic laws of conservation of momentum and energy. These derived differential equations are then rendered dimensionless by incorporating the normalization parameters, which are subsequently followed by the implementation of mild stenotic supposition. The parabolic equations are solved numerically by using the explicit finite difference technique. After that, these numerical calculations are used to simulate several flow characteristics such as velocity, impedance, and wall shear stress using the set of emerging parameters taken from literature. The influence of these emerging parameters on the flow characteristics reveals that the velocity of the hybrid blood flow stream decelerates due to the presence of an induced magnetic field having the inclusion of nanoparticles. Finally, the global behavior of hybrid blood flow within the curved stenosed channels is sketched and analyzed by using various streamline plots. [ABSTRACT FROM AUTHOR]

The effect of source/sink heat location and size on Magneto-hydrodynamic mixed convection in hybrid nanofluid of Al2O3-Cu/Water within the L-shaped cavity is studied in this paper. Two uniform heat sources are put at the corners of the bottom walls of enclosure and the beginning and the end of L-shape enclosure set to be at the cold temperature. The other parts of enclosure’s walls are supposed to be insulated. The finite difference method and Boussinesq approximation is utilized to discrete the governing equations. The fundamental flow physics and thermal behavior are explored in terms of pertinent parameters such as the effects of sink/source heat generation, magnetic field and angle, Hartmann number, cavity length ratio, and hybrid volume fraction on average and surface Nusselt number, streamlines, isotherms, and entropy generation are studied. The results demonstrate that maximum amount of the sink power causes the best heat transfer performance.

The current reconnaissance emphasis on spanwise cosinusoidally fluctuating temperature along with time deepened as well as radiation absorption on unsteady magneto‐hydrodynamics free convective heat and mass transfer boundary layer flow with viscous dissipation, constant suction normal to an infinite hot vertical porous plate in the existence of chemical reaction by means of heat generation. The analytical solution of nonlinear PDE's governing the flow has been accomplished by employing a second‐order multiple regular perturbation method within the stipulated boundary conditions. Velocity, temperature, concentration as well as Sherwood have been exemplified graphically; along with Skin friction, and Nusselt numbers are ascertained in tabular form. Eventually, it was found that velocity, temperature, and Skin friction accelerated with the accumulative values of Eckert number and radiation absorption, but conflicting results emerged in the case of Prandtl number. Contemporaneously Sherwood's number depreciated with the magnification of the chemical reaction parameter as well as the Schmidt number. [ABSTRACT FROM AUTHOR]

A numerical study was performed to analyze the impact of the combination of several factors on heat transfer rate, flow behavior, and entropy generation in a hybrid nanofluid occupying a porous trapezoid enclosure containing a rotating inner tube. The governing equations were discretized and solved using the Finite Element Method using Comsol multiphysics. The effects of the Darcy and Hartman number, nanoparticle volume fraction (from 0 to 6%), the utilization of various zigzag patterns of the hot wall, and the rotation speed of the inner tube (Ω = 100. 250 and 500) are illustrated and discussed in this work. The outputs reveal that flow intensity has an inverse relationship with Hartman number and a direct relationship with the Darcy number and the velocity of the inner tube, especially at high numbers of undulations of the zigzag hot wall (N = 4); also, intensification of heat transfer occurs with increasing nanoparticle volume fraction, Darcy number and velocity of the inner tube. In addition, entropy generation is strongly affected by the mentioned factors, where increasing the nanoparticle concentration augments the thermal entropy generation and reduces the friction entropy generation; furthermore, the same influence can be obtained by increasing the Hartman number or decreasing the Darcy number. However, the lowest entropy generation was found for the case of Ø = 0, Ha = 0 and Da = 0.01. [ABSTRACT FROM AUTHOR]

Relativistic jets and disc-winds are energetic phenomena exhibited by various sources, including Active Galactic Nuclei (AGNs) and black hole X-ray binaries (BH-XRBs). Despite recent observational advances in unraveling the region close to the black hole, many aspects of jet launching and particularly the jet-disc connection in these sources are not fully understood. This study investigates the role of the aspect ratio (H/r) of the underlying accretion disc on the jet launching. In this regard, we use an axisymmetric GRMHD framework with adaptive mesh refinement and initialize our simulations with a thin accretion disc in hydro-static equilibrium. In our simulations, we observe Blandford & Znajek (BZ) jet, Blandford & Payne (BP) disc-wind and B tor dominated disc-wind. We find that the aspect ratio of the underlying accretion disc plays a crucial role in the dynamical properties of jet and disc-winds. For an accretion disc with a low aspect ratio, we observe the BZ-jet be thinner and the B tor dominated disc-wind component of the disc-wind to be broader. Further, the BP disc-wind launching radius is closer for an accretion disc with a low aspect ratio. Such a variable launching area of BP disc-wind with an aspect ratio of the underlying disc can have potential implications on understanding the origin of jet dichotomy. Additionally, from the temporal evolution of magnetic flux, we also find the discs with higher aspect ratios are more susceptible to transform into a magnetically arrested disc (MAD) and result in more intermittent wind and jet properties. [ABSTRACT FROM AUTHOR]

Coronal mass ejections (CMEs) are more energetic than any other class of solar phenomena. They arise from the rapid release of up to 1033 erg of magnetic energy mainly in the form of particle acceleration and bulk plasma motion. Their stellar counterparts, presumably involving much larger energies, are expected to play a fundamental role in shaping the environmental conditions around low‐mass stars, in some cases perhaps with catastrophic consequences for planetary systems due to processes such as atmospheric erosion and depletion. Despite their importance, the direct observational evidence for stellar CMEs is almost non‐existent. In this way, numerical simulations constitute extremely valuable tools to shed some light on eruptive behavior in the stellar regime. Here, we review recent results obtained from realistic modeling of CMEs in active stars, highlighting their key role in the interpretation of currently available observational constraints. We include studies performed on M‐dwarf stars, focusing on how emerging signatures in different wavelengths related to these events vary as a function of the magnetic properties of the star. Finally, the implications and relevance of these numerical results are discussed in the context of future characterization of host star‐exoplanet systems. [ABSTRACT FROM AUTHOR]

This paper examines the two-dimensional laminar steady magnetohydrodynamic doublediffusive mixed convection in a curved enclosure filled with different types of nanofluids. The enclosure is differentially heated and concentrated, and the heat and mass source are embedded in a part of the left wall having temperature Th (>Tc) and concentration ch (>cc). The right vertical wall is allowed to move with constant velocity in a vertically upward direction to cause a shear-driven flow. The governing equations along with the boundary conditions are transformed into a nondimensional form and are written in stream function-velocity formulation, which is then solved numerically using the Bi-CGStab method. Based on the numerical results, the effects of the dominant parameters such as Richardson number (1 ≤ Ri ≤ 50), Hartmann number (0 ≤ Ha ≤ 60), solid volume fraction of nanoparticles (0:0 ≤ ɸ ≤ 0:02), location and length of the heat and mass source are examined. Results indicate that the augmentation of Richardson number, heat and mass source length and location cause heat and mass transfer to increase, while it decreases when Hartmann number and volume fraction of the nanoparticles increase. The total entropy generation rises by 1:32 times with the growing Richardson number, decreases by 1:21 times and 1:02 times with the rise in Hartmann number and nanoparticles volume fraction, respectively. [ABSTRACT FROM AUTHOR]

The current study pertains to heat and mass transportation of magnetic fluid flow having dilute diffusion of nanoparticles and motile microorganisms over a permeable stretched sheet to examine the influence of thermal radiation and activation energy. Similarity functions are utilized to convert the highly mixed non-linear partial differential equations into higher-order non-linear ordinary differential equations. Five coupled equations are derived to be resolved numerically by employing a computing function Bvp4c, built-in Matlab. Two sets of thermal boundaries prescribed surface temperature (PSF) and prescribed heat flux (PHF) are considered. Basic physical quantities, temperature distribution, concentration, velocity field, and motile micro-organism profiles are observed as influenced by emerging parameters. The microorganisms distribution undergoes decreasing behavior against growing values of bio-convection Lewis number and Peclet number. These results are highly useful in the application of heat-transmitting devices and microbial fuel cells. It is seen that decreasing trend is observed in velocity profile when parameters Nr and Nc are uplifted. Also, the motility of the nanofluid decreases when the Lb parameter is raised. On the other hand, an increase in Peclet number Pe showed a rising trend in motility profile. Additionally, the implications of Brownian motion, Rayleigh number, Bioconvection Lewis number thermophoresis parameter, Peclet number, and buoyancy ratio parameter are discussed. Moreover, the obtained outcomes are validated as compared to the existing ones as limiting cases. Representative findings for microorganism concentration, skin friction coefficient, temperature gradient, local Sherwood number and density number of motile microorganisms, velocity field, temperature, the volumetric concentration of nanoparticles, are discussed in tabulated and graphical form. [ABSTRACT FROM AUTHOR]

The objective of the present work is to investigate the influence of nanoparticles of copper within the base fluid (water) on magneto-hydrodynamic mixed-convection flow in a square cavity with internal generation. A control finite volume method and SIMPLER algorithm are used in the numerical calculations. The geometry is a lid-driven square cavity with four interior square adiabatic obstacles. A uniform heat source is located in a part of the left wall and a part of the right wall of the enclosure is maintained at cooler temperature while the remaining parts of the two walls are thermally insulated. Both the upper and bottom walls of the cavity are considered to be adiabatic. A comparison with previously published works shows a very good agreement. It is observed that the Richardson number, Ri, significantly alters the behavior of streamlines when increased from 0.1 to 100.0 . Also, the heat source position parameter, D , significantly changes the pattern of isotherms and its strength shifted when D moves from 0.3 to 0.7 .