Natural Convection from a Permeable Sphere Embedded in a Variable Porosity Porous Medium Due to Thermal Dispersion

The laminar natural convection boundary-layer flow of an electricallyconducting fluid from a permeable sphere embedded in a porous medium with variable porosity is considered. The non-Darcy effects including convective, boundary, inertial and thermal dispersion effects are included in this analysis. The sphere surface is maintained at a constant heat flux and is permeable to allow for possible fluid wall suction or blowing. The resulting governing equations are nondimensionalized and transformed into a nonsimilar form and then solved numerically by using the secondlevel local non-similarity method that is used to convert the non-similar equations into a system of ordinary differential equations. Comparisons with previously published work are performed and excellent agreement is obtained. A parametric study of the physical parameters is conducted and a representative set of numerical results for the velocity and temperature profiles as well as the local skin-friction coefficient and the Nusselt number are illustrated graphically to show interesting features of Darcy number, inertia coefficient, the magnetic parameter, dimensionless coordinate, dispersion parameter, the Prantdl number and suction/blowing parameter

Unsteady slip flow of amicropolarnanofluid over an impulsively stretched vertical surface

The unsteady mixed convective flow of micropolarnanofluid over an impulsively stretched vertical surface has been examined. A model has been developed to analyze the behavior of nanofluids in presentmicropolar fluids studied numerically for both cases of assisting and opposing flow taking into account the thermal convective boundary condition. A model has been developed to analyze the behavior of nanofluids containing metallic nanoparticles as copper (Cu)and nonmetallic nanoparticles as alumina (A  in water-micropolarnanofluidhave been considered. The governing partial differential equations have been transformed to non-similar differential equations then have been solved numerically by using theRunge-Kutta-Fehlberg method of seventh order (RKF7). The results have been compared with the published results and are found in excellent agreement

Unsteady slip flow of amicropolarnanofluid over an impulsively stretched vertical surface

773-782The unsteady mixed convective flow of micropolarnanofluid over an impulsively stretched vertical surface has been examined. A model has been developed to analyze the behavior of nanofluids in presentmicropolar fluids studied numerically for both cases of assisting and opposing flow taking into account the thermal convective boundary condition. A model has been developed to analyze the behavior of nanofluids containing metallic nanoparticles as copper (Cu)and nonmetallic nanoparticles as alumina (A  in water-micropolarnanofluidhave been considered. The governing partial differential equations have been transformed to non-similar differential equations then have been solved numerically by using theRunge-Kutta-Fehlberg method of seventh order (RKF7). The results have been compared with the published results and are found in excellent agreement

Mixed Convective Flow of Micropolar Nanofluid across a Horizontal Cylinder in Saturated Porous Medium

The micropolar nanofluids are the potential liquids that enhance the thermophysical features and ability of heat transportation instead of base liquids. Alumina and Titania nanoparticles are mixed in a micropolar fluid. The impact of convective boundary condition is also examined with assisting and opposing flows of both nanofluids. The main objective of this study is to investigate mixed convective flow and heat transfer of micropolar nanofluids across a cylinder in a saturated porous medium. Non-similar variables are used to make the governing equations dimensionless. The local similar and non-similar solutions are obtained by using the Runge-Kutta-Fehlberg method of seventh order. The impacts of various embedded variables on the flow and heat transfer of micropolar nanofluids are investigated and interpreted graphically. It is demonstrated that the skin friction and heat transfer rates depend on solid volume fraction of nanoparticles, Biot number, mixed convection, and material parameters

Magnetic williamson hybrid nanofluid flow around an inclined stretching cylinder with joule heating in a porous medium

The study of an inclined stretching cylinder in a porous medium holds significant implications for understanding complex fluid dynamics and heat transfer phenomena, mainly when influenced by a hybrid nanofluid containing Cu and Al2O3, Joule heating, and a magnetic field in the presence of Williamson fluid. The nonlinear ordinary differential equations are derived by applying pertinent similarity transformations to partial differential equations. Subsequently, these non-dimensional ordinary differential equations are transformed into a system of first-order ODEs and numerically solved using Maplesoft's symbolic computation software MAPLE 2023. The influence of governing parameters on dimensionless velocity, temperature, concentration, skin friction, heat, and mass transfer rates is investigated. This investigation is crucial for various practical applications, including geothermal reservoirs, enhanced oil recovery, and environmental processes involving porous media. It is demonstrated that Biot and Eckert numbers and nanofluid parameters contribute to increased surface temperature, while the Lewis number leads to a decrease in dimensionless concentration. Moreover, the curvature parameter is associated with an increase in dimensionless concentration, and skin friction demonstrates a direct relationship with the magnetic parameter while inversely correlating with the cylinder's curvature.These results contribute to the scientific understanding of these complex interactions and provide valuable insights for engineering applications, such as designing efficient heat exchangers, optimizing cooling systems, and advancing technologies involving fluid flow and magnetic fields