Radiative MHD Research Articles

Radiative MHD Casson Non-Newtonian Nanofluid Slip Flow Induced by Stretching Cylinder: A Numerical Approach

Objectives: This article investigates the continuous magnetohydrodynamics slip flow across an extending cylinder, including heat radiation and free stream velocity. The proposed model incorporated the Brownian motion parameter and thermophoresis. Methods: Applying the similarity transformation to a system of partial differential equations yields an ordinary differential equation of first order. Since, there is the nonlinear nature of the modified equations, these ordinary differential equations are addressed by employing mathematical modeling. The shooting process has been embraced to solve changed equations by implementing the following Runge-Kutta Fehlberg method. Findings: Graphical representations are used to show how several fluid factors, such as Casson fluid parameter, free stream velocity, thermophoresis, magnetic parameter, Brownian motion parameter, heat generation parameter, Lewis number, radiation parameter, chemical reaction and curvature parameter affect concentration, temperature and velocity. Results for physical quantity of interest are also computed and reported in tabular form. The study's main findings showed that nanoparticle temperatures rise with greater Brownian motion parameter values, whereas nanoparticle concentration falls with higher heat radiation parameter values. Additionally, it is found that with rise in Lewis number rises as 0.1, 0.4, 0.7, 1.0, 1.3, heat transfer rate falls down by 21.19%. The outcomes are calculated using the MATLAB software. Novelty: This technique's validity is defended by comparing its most recent findings to previously published results and successfully meeting the convergence criteria. The present work emphasizes the analysis of free stream flow in the cylindrical area, specifically in the existence of partial slip and heat radiation, under convective circumstances. This study has significant implications for electronic devices such as processors as well as many businesses and the field of biological and medical sciences. The present investigation aims to support production businesses in achieving the desired level of quality of their products by effectively managing the transport phenomena. Keywords: Stretching cylinder, Heat radiation, Brownian motion, Thermophoresis, Non-Newtonian nanofluid, Shooting technique

The influence of a non-uniform heat source/sink and Joule heating on the convective motion of a micropolar fluid in a chemically radiative MHD medium across a stretched sheet

The objective of the present exploration is to examine impactions of radiation, a non-uniform intensity source, and a permeable medium on a temperamental MHD blended convective micropolar liquid over an extended sheet subject to Joule heating. To transform the formulated problem into ordinary differential equations, the applicable similarity transformation is implemented. By utilizing R-K-F 4th -5th order approach with shooting method with MATLAB, the numerical solution is obtained. For the relevant profiles, the dimensionless parameters are visually displayed and described. Skin friction, the Nusselt number, and the Sherwood number have all been calculated using the answer found for the velocity, temperature, and concentration. With the assistance of line graphs, the impact of different flow factors being introduced into the problem is addressed. This research is conducted on the implications of MHD, porous, thermal radiation, viscous dissipation, Joule heating, non-liner thermal radiation and chemical reaction. For large values of micropolar parameter, the temperature is reduced and velocity and angular momentum distributions are raised. With the thermal radiation parameter, the temperature distribution gets better and thermal boundary layer is improved while the large values of Eckert number and non-uniform heat source or sink parameters, thermal boundary layer is improved. The higher thermal conductivity is proportional to the thickness of the thermal boundary layer. The concentration profile degrades with higher Schmidt number and chemical reaction parameter values. The current examination pertains to the significant subject matter of cooling of systems, artificial heart identification, oil-pipelined frictions, flow-tracers.

Coronal magnetic field and emission properties of small-scale bright and faint loops in the quiet Sun

Context. The present study provides statistical information on the coronal magnetic field and intensity properties of small-scale bright and faint loops in the quiet Sun. Aims. We aim to quantitatively investigate the morphological and topological properties of the coronal magnetic field in bright and faint small-scale loops, with the former known as coronal bright points (CBPs). Methods. We analyse 126 small-scale loops of all sizes using quasi-temporal imaging and line-of-sight magnetic field observations. These observations are taken by the Atmospheric Imaging Assembly (AIA) in the Fe XII 193 Å channel and the Helioseismic Magnetic Imager (HMI) on board the Solar Dynamics Observatory. We employ a recently developed automatic tool that uses a linear magneto-hydro-static (LMHS) model to compute the magnetic field in the solar atmosphere and automatically match individual magnetic field lines with small-scale loops. Results. For most of the loops, we automatically obtain an excellent agreement of the magnetic field lines from the LMHS model and the loops seen in the AIA 193 Å channel. One stand-out result is that the magnetic field is non-potential. We obtain the typical ranges of loop heights, lengths, intensities, mean magnetic field strength along the loops and at loop tops, and magnetic field strength at loop footpoints. We investigate the relationship between all those parameters. We find that loops below the classic chromospheric height of 1.5 Mm are flatter, suggesting that non-magnetic forces (one of which is the plasma pressure) play an important role below this height. We find a strong correlation (Pearson coefficient of 0.9) between loop heights and lengths. An anti-correlation is found between the magnetic field strength at loop tops and loop heights and lengths. The average intensity along the loops correlates stronger with the average magnetic field along the loops than with the field strength at loop tops. Conclusions. The latter correlation indicates that the energy release in the loops is more likely linked to the average magnetic field along the loops than the field strength on the loop tops. In other words, the energy is probably released all along the loops, but not just at the loop top. This result is consistent with a recent benchmarking radiative 3D MHD model.

Dust-evacuated Zones near Massive Stars: Consequences of Dust Dynamics on Star-forming Regions

Stars form within dense cores composed of both gas and dust within molecular clouds. However, despite the crucial role that dust plays in the star formation process, its dynamics is frequently overlooked, with the common assumption being a constant, spatially uniform dust-to-gas ratio and grain size spectrum. In this study, we introduce a set of radiation-dust-magnetohydrodynamic simulations of star-forming molecular clouds from the STARFORGE project. These simulations expand upon the earlier radiation MHD models, which included cooling, individual star formation, and feedback. Notably, they explicitly address the dynamics of dust grains, considering radiation, drag, and Lorentz forces acting on a diverse size spectrum of live dust grains. We find that once stars exceed a certain mass threshold (∼2 M ⊙), their emitted radiation can evacuate dust grains from their vicinity, giving rise to a dust-suppressed zone of size ∼100 au. This removal of dust, which interacts with gas through cooling, chemistry, drag, and radiative transfer, alters the gas properties in the region. Commencing during the early accretion stages and preceding the main-sequence phase, this process results in a mass-dependent depletion in the accreted dust-to-gas (ADG) mass ratio within both the circumstellar disk and the star. We predict that massive stars (≳10 M ⊙) would exhibit ADG ratios that are approximately 1 order of magnitude lower than that of their parent clouds. Consequently, stars, their disks, and circumstellar environments would display notable deviations in the abundances of elements commonly associated with dust grains, such as carbon and oxygen.

Mathematical modeling and analysis for radiative MHD peristaltic flow of Bingham nanofluid

Mathematical modeling and analysis for radiative MHD peristaltic flow of Bingham nanofluid

Impact of the Brownian motion and thermophoretic diffusion during the radiative MHD hybrid nanofluid flow past a stretching sheet

The article aims to analyze the effects of thermophoretic and Brownian motion on steady three-dimensional magnetohydrodynamics with fully developed natural convective hybrid nanofluid flow past a bidirectionally extending sheet. We assumed the water-based copper and aluminum nanoparticles suspension under the influence of the rotational effect, nonlinear chemical reaction, thermal radiations, viscous dissipation, and heat source. The flow field is modeled with the help of the basic equations. Furthermore, the problem is reduced to ordinary differential equations (ODEs) with the similarity variables. The reduced system of ODEs is solved with the semianalytical method (homotopy analysis method). The results for the state variables are displayed through graphs tables for various pertinent parameters. The thermal profile falls with the higher values of the Brownian and thermophoresis parameters, while the concentration profile shows an opposite trend with the increasing values of the Brownian parameter. Also, the slip parameter decreases both the thermal and concentration profiles as well as the surface drag. The velocity profiles along both directions fall with the higher magnetic strength and porosity parameters. The heat source and radiations parameter enhances the thermal profile with increasing values. The study also recommends the opposite trends for the axial and transverse velocities with increasing value of the stretching ratio factor. The proposed method convergence is present through [Formula: see text] curves for the regions [Formula: see text] [Formula: see text] [Formula: see text] and [Formula: see text] The skin friction and Nusselt number are displayed through tables numerically for various values of volume fraction and other important parameters.

Assessing the Efficacy of Hybrid Nanofluid within a Non-Newtonian Reiner-Philippoff Model, Incorporating MHD and Thermal Radiation Past a Stretching/Shrinking Sheet

Hybrid nanofluids are making waves in industry because of their superior thermal efficiency and innovative designs. Their usefulness extends to many other sectors and domains of study. The volume fraction of Cu–Al2O3 and Ag–TiO2 hybrid nanoparticles in nanofluids will be studied to determine their impact on heat transmission and flow. The study also considers the presence of heat radiation, a magnetic field, and other relevant factors. The non-Newtonian Reiner-Philippoff model was employed to investigate the flow's shear thickening and thinning properties. The combined effects of suction and a contracting surface form a boundary for the surface. The reduced partial differential equation (PDE) is solved using the MATLAB tool bvp4c following the similarity transformation method. The shrinking sheet shows that the dual solution converges to critical points, and the stability study verified that the first one is stable and physically trustworthy. The mathematical modelling developed for nanofluid hybrids has exhibited a significant impact on the overall heat flow, which can be attributed to the variation in the parameters that influence it. Enhancement in magnetic parameter (+2.26%), suction (+2.99%), and nanoparticle fractional volume of metal oxide (+0.4%) were identified as factors that accelerated heat transfer to the pioneering Cu–Al2O3 nanofluid hybrid, according to the study. Besides, the second hybrid of Ag–TiO2 nanofluids had a reduced heat transfer rate due to changes in thermal radiation (-2.14%) and Reiner parameter-Philippoff fluid (-0.14%).

Radiation MHD Simulations of Soft X-Ray Emitting Regions in Changing Look AGN

Strong soft X-ray emission called soft X-ray excess is often observed in luminous active galactic nuclei (AGN). It has been suggested that the soft X-rays are emitted from a warm (T = 106 ∼ 107 K) region that is optically thick for the Thomson scattering (warm Comptonization region). Motivated by the recent observations that soft X-ray excess appears in changing look AGN (CLAGN) during the state transition from a dim state without broad emission lines to a bright state with broad emission lines, we performed global three-dimensional radiation magnetohydrodynamic simulations, assuming that the mass accretion rate increases and becomes around 10% of the Eddington accretion rate. The simulation successfully reproduces a warm, Thomson-thick region outside the hot radiatively inefficient accretion flow near the black hole. The warm region is formed by efficient radiative cooling due to inverse Compton scattering. The calculated luminosity 0.01−0.08 L Edd is consistent with the luminosity of CLAGN. We also found that the warm Comptonization region is well described by the steady model of magnetized disks supported by azimuthal magnetic fields. When the antiparallel azimuthal magnetic fields supporting the radiatively cooled region reconnect around the equatorial plane of the disk, the temperature of the region becomes higher by releasing the magnetic energy transported to the region.

Data analysis of non-linear radiative electro-periodic MHD flow past a stretching sheet with activation energy impact

Electro-periodic Magneto-hydrodynamics (EPMHD), activation energy, and non-linear radiation are pivotal elements in engineering and industry also contribute to advancements in fields like heat transfer, materials science, and chemical engineering. Through similarity transformation, governing partial differential equations simplify into ordinary differential equations. Precise computational solutions are derived using the Nachtsheim-Swigert shooting iteration method (NSSIM) and the reliable 6th-order Runge-Kutta integration algorithm (RKIA). The profiles of velocities, temperatures, concentrations, skin friction, heat and mass transfer rate are presented by graphically. The novel aspect of this research is that thermal performance is enhanced by non-linear radiation by around 2.28%, whereas linear radiation only produces a 0.28% improvement in thermal performance. Also the mass transfer rate experiences a decrease of about 25.76% with increasing chemical reactions in the presence of activation energy and a more substantial 62.22% reduction in its absence, notably showing a comparatively milder decline of 36.46% in the presence of activation energy than in its absence. Furthermore, this study yields three novel linear regression equations, skillfully derived from the numerical and graphical results. This research have practical applications in understanding and optimizing processes involving fluid dynamics, such as the behavior of certain materials or substances subjected to stretching or deformation.

Influence of suction and injection on the electrical magnetohydrodynamic behavior of nano-fluid in a nonlinear radiative flow over an extending surface

The present communication aims to investigate the behavior of a radiative electrical MHD Casson nanofluid flowing over a stretched surface, under the influence of nonlinear thermal radiation, and suction/injection effects. The governing equations include parameters for temperature and concentration, which are adjusted based on the dependence of viscosity and thermal conductivity, thus enhancing the fluid flow properties. By using similarity transformations, the system of PDEs is converted to an ODE, which is then numerically solved using the well-known fourth-order Runge–Kutta integration strategy based on the shooting method. The impacts of operating parameters on velocity, temperature, and concentration profiles were explained and examined through tables and graphs. Temperature and concentration are increased as the injection ( S < 0 ) increases . However, they show decrement when the suction ( S > 0 ) increases . The novelty of this study focuses on the mathematical development of the flow problem with significant results and also investigating the impact of electric field on velocity of the fluid flow and shear stress. These results are applicable in manufacturing of stretchable materials.

A finite difference study of radiative mixed convection MHD heat propagating Casson fluid past an accelerating porous plate including viscous dissipation and Joule heating effects

A finite difference numerical simulation scrutiny is executed to evaluate the combined impacts of heat generation, buoyancy forces, viscous dissipation and Joule heating in unsteady hydro-magnetic mixed convective chemically reactive and radiative Casson fluid flowing along an exponentially accelerating permeable vertical plate engrossed in a porous media by considering ramp surface concentration and temperature. The dimensionless non-linear coupled PDEs describing the flow model are dealt numerically by adopting the competent implicit Crank-Nicolson finite difference procedure. The variance of velocity, temperature, and concentration distributions are exposed via graphical representations due to the dissimilarity of the flow restrained parameters. Computational outcomes of the skin-friction, Nusselt and the Sherwood numbers are portrayed in the tabular pattern. The final outcomes of the research exposed that the impacts of thermal radiation, viscous dissipation, and heat production parameters enlarges the temperature and velocity distributions. The fluid motion deflates for growing Casson parameter and magnetic field intensity. The rising chemical reaction parameter suppresses the concentration and velocity distributions. Very importantly it is distinguished that fluid momentum, temperature, and concentration are quicker in the instance of isothermal plate temperature than ramp wall temperature. This kind of research may find specific industrial and medical utilizations such as glass manufacturing, crude oil purification, lubrication, paper production, blood transport study in cardiovascular design, etc.

Effects of MHD and thermal radiation on non-Newtonian fluid with Cattaneo–Christov heat over a stretching flow surface

In this study, we are investigating the flow of an incompressible Williamson fluid using a Cattaneo–Christov heat flux model, with consideration for a magnetic Reynolds number that is not high. This fluid flows over a linearly stretched 2-D surface and is affected by a magnetic field, thermal radiation-diffusion, and heat generation. To model the Williamson flow, we apply a boundary layer approximation and develop the ordinary differential equations. The system of differential equations is transformed into a system of ordinary differential equations using a suitable transformation. We utilize the Iterative Runge–Kutta fourth-order scheme to numerically solve the boundary conditions associated with the nonlinear, dimensionless ordinary differential equations. Graphical representations of the results are employed to analyze the impact of physical properties on velocity, temperature, and concentration, with the numerical results presented in tabular form. Upon comparing our findings with previously published results, we have found them to be in good agreement. The velocity decreases as the Williamson fluid factor gradually increases. Williamson fluids are recognized for their shear thinning behavior, wherein viscosity decreases as the shear rate increases. However, higher parameter values can lead to increased fluid viscosity, potentially reducing the degree of shear thinning. This phenomenon results in a more uniform viscosity profile across varying shear rates, contributing to a reduced velocity distribution within the fluid.

New closed-form exact solution of action induced magnetic field and fluid wall interaction on radiative mixed convective heat transfer MHD fluid flow inside a vertical walls with suction/injection and pressure gradient

The novelty of this article is not only the adaptation of a new closed-form exact method originally used to solve initial value problems but also to solve boundary value problems whose boundary conditions contain variable values. The boundary conditions of governing equations of velocity, induced magnetic, and temperature for the current study contain different parameters such as (Wall ambient temperature, Knudsen number, and Fluid wall interaction parameter) and, contain gradient of velocity, induced magnetic, and temperature. Using the Laplace transform method, the exact solution of the governing equations was obtained, and the effects of different parameters on its behavior in three different cases of wall-ambient temperature difference ratio was studied. I would also like to clarify that the reason for paying attention to such studies is that they contribute effectively and usefully in many fields and applications, such as molten metal MHD pumps, the design of small pumps, molten salt, and heat exchangers.

Radiative MHD Boundary Layer Flow and Heat Transfer Characteristics of Fe-Casson Base Nanofluid over Stretching/Shrinking Surface

In this paper, there is considered MHD boundary layer flow and heat transfer characteristics of Fe-Casson base nanofluid over an exponentially stretching/shrinking surface along the heat source/sink and Newtonian heating effects. In this regard, to develop the system of the governing equations, the one phase model named as Tiwari and Das model is considered with iron nanoparticles. The non-linear governing PDEs are first changed into the system of ODEs using suitable similarity transformations. Later on, the equations are solved numerically by using bvp4c in Matlab software. Effects of certain physical parameters on skin friction coefficient and the local Nusselt number are illustrated graphically. Moreover, the velocity and temperature profiles are examined to observe the influence of various physical parameters such as, Casson, magnetic, suction, radiation, Newtonian heating, heat source/sink and the nanoparticles volume fractions. It is seen that an increase in Casson, magnetic, suction and the nanoparticle volume fractions decrease the velocity profiles for both shrinking and shrinking cases of surface. The temperature profile recedes due to augmentation of Prandlt number and the suction parameter for both stretching/shrinking case while increases with increase in Magnetic, radiation and nanoparticles volume fractions.

Suction/Injection Influence on Electrical MHD Nano-Fluid on a Nonlinear Radiative Flow Over a Stretching Sheet

The current communication’s goal is to look at how a radiative electrical MHD Casson nanofluid moves through a stretched sheet while being affected by nonlinear thermal radiation and suction/injection. The controlling equations incorporate a temperature and concentration parameter that is modified viscosity/thermal conductivity dependent in order to enrich the blood flow. By using similarity transformations, the system of PDEs is converted to an ODE, which is then numerically solved using the well-known fourth-order Runge-Kutta integration strategy based on the shooting method. The impacts of operating parameters on velocity, temperature and concentration profiles were explained and examined through tables and graphs. Temperature and concentration are increased as the injection (S &lt; 0) increases. However, they show decrement when the suction (S &gt; 0) increases.

Effects of thermophoresis and Brownian motion on radiative MHD hybrid nanofluid flow over a stretching sheet with convective boundary conditions: A homotopic approach

Energy efficiency is the highest need of present times to meet the challenges of global energy demands. Nanofluids have proved to possess dynamic thermal characteristics in many experimental and theoretical studies during recent years. Nowadays, a variety of nanomaterials are accessible, and among these alloys of aluminum, AA7072 and AA7075 are important due to their unique functional characteristics. These alloys are widely used in the engineering of aircraft, spacecraft, buildings, and so on. Aiming to highlight the importance of nanofluids, this article analyses the heat and mass transfer for magnetohydrodynamic hybrid nanofluid flow on a stretching sheet of gyrotactic microorganisms. Additionally, the impacts of chemical reactions, activation energy, Peclet number, thermophoresis, Lewis number, Brownian motion, and thermal radiation are also studied. The governing equations from Partial differential equations into Ordinary differential equations are transformed with the support of resemblance transformations, and the solution is obtained with HAM techniques. The numerical findings are presented in figures and tabular form with the Mathematica program. The obtained results are explained from a physical point of view in detail. An assessment between the proposed and current model is described under specific flow parameter assumptions to validate the analysis. It is revealed that the outcomes are consistent with previous findings. The numbers of engineering importance like skin friction and heat transfer rate are explained for practical relevance. The impacts of nanoparticle loading show interesting results. It is perceived that an escalating trend is noted in the nanoparticle temperature through thermal radiation and thermophoretic parameters.

The Effects of an Aligned Magnetic Field on Nanofluid Flow with Newtonian Heating

Magnetic field involvement can influence heat absorption in electrically conducting fluid flow, which is useful in the control of features of final products in industries such as radiation therapy, aeronautics, and MHD generators. Consequently, this study investigates the effect of an aligned magnetic field on nanofluid flow over a stretching sheet with the boundary condition of Newtonian heating. Steady nanofluid flow with copper as chosen nanoparticles and water as conventional base fluid is considered. The problem is governed by a system of nonlinear boundary layer equations with appropriate boundary conditions which are then transformed into non-dimensionless equations using an appropriate similarity transformation. A numerical approach known as Keller-Box method is used to solve the transformed governing equations. The numerical solutions obtained are presented graphically in the form of velocity and temperature profiles for different values of aligned angle of magnetic field, Newtonian heating parameter, Prandtl number and nanoparticles volume fraction. A significant increase in aligned angle results in a decrease in fluid velocity, but an increase in temperature profile of nanofluid flow. The increment in the Newtonian heating parameter as well as the nanoparticle volume fraction also causes the temperature to increase.

Chemically Radiative MHD Flow of a Micropolar Nanofluid over a Stretching/Shrinking Sheet with a Heat Source or Sink

Chemically Radiative MHD Flow of a Micropolar Nanofluid over a Stretching/Shrinking Sheet with a Heat Source or Sink

Radiative and dissipative MHD Eyring–Powell nanofluid bioconvective flow through peristaltic waves in the presence of bilateral chemical reaction with Arrhenius activation energy: Entropy optimization

The novel characteristics of nanofluids made them potentially important in the heat transfer mechanisms happening in industrial and medical processes, such as electronic devices, pharmacological techniques, hybrid combustion engines, thermal management of cars, refrigerator, chiller, temperature of gases reduction, and so on. In comparison to base fluid, these procedures have a propensity to improve thermal conductivity and convective transference of heat. This distinctive aspect has recently generated interest in nanofluids through various fluid flow models. The issue at hand involves the peristaltic flow of magnetohydrodynamics Eyring–Powell nanofluids through a microchannel containing oxytactic bacteria and nanoparticles. For a thorough analysis of irreversibility optimization, the analysis of entropy is additionally taken into consideration. To comprehend the flow physics associated with bolus formation and the effect of reflux on the micro vessel, a 3-D computational fluid dynamic analysis is performed. The effects of bilateral chemical interaction with nonlinear mixed convection and Arrhenius activation energy are considered in the present analysis. The complexity of the system was achieved through a numerical approach based on the concepts of small Reynolds number and large wavelength. The resulting nonlinear coupled differential equation system is solved numerically using the built-in command in MATHEMATICA (Parametric ND Solve Function). To perform a thorough comparative examination for various values of the considered sections of the channel, graphs have been used. Some of the investigation’s findings are the entropy profile has been improved for incremental values of Hartmann number and Brinkmann number whereas the axial velocity shows a downward trend for the highest values of the Hartmann number and the material fluid parameter.

Nonlinear stretched flow of a radiative MHD Prandtl fluid with entropy generation and mixed convection

Nonlinear stretched flow of a radiative MHD Prandtl fluid with entropy generation and mixed convection