MHD Flow of a Micropolar Fluid past a Stretched Permeable Surface with Heat Generation or Absorption

This work considers steady, laminar, MHD flow of a micropolar fluid past a stretched semi-infinite, vertical and permeable surface in the presence of temperature dependent heat generation or absorption, magnetic field and thermal radiation effects. A set of similarity parameters is employed to convert the governing partial differential equations into ordinary differential equations. The obtained self-similar equations are solved numerically by an efficient implicit, iterative, finite-difference method. The obtained results are checked against previously published work for special cases of the problem in order to access the accuarcy of the numerical method and found to be in excellent agreement. A parametric study illustrating the influence of the various physical parameters on the skin friction coefficient, microrotaion coefficient or wall couple stress as well as the wall heat transfer coefficient or Nusselt number is conducted. The obtained results are presented graphically and in tabular form and the physical aspects of the problem are discussed

Thermal Radiation Effects on Mhd Free Convection Flow of a Micropolar Fluid Past a Stretching Surface Embedded in a Non-Darcian Porous Medium

A comprehensive study of thermal radiation on a steady two-dimensional laminar flow of a viscous incompressible electrically conducting micropolar fluid past a stretching surface embedded in a non-Darcian porous medium is analyzed numerically. The governing equations of momentum, angular momentum, and energy equations are solved numerically using Runge- Kutta fourth order method with shooting technique. The effects of various parameters on the velocity, microrotation, and temperature field as well as skin friction coefficient, and Nusselt number are shown graphically and in tabulated. It is observed that the micropolar fluid helps in the reduction of drag forces and also acts as a cooling agent. KEYWORDS: Micropolar fluid, Free convection, Darcy number,Radiation, MHD,  Porous medium

Flow Analysis on Boundary Layer of Porous Horizontal Circular Cylinder Filled by Viscoelastic-Micropolar Fluid

This study emphasis on the analysis of boundary layer flow of viscoelastic fluid with microrotation moving over a porous horizontal circular cylinder. The model of the problem is based on Navier Stokes equations which involved continuity, momentum and micro inertia equations. The mentioned equations are first undergo Boussinesq and boundary layer approximation before transforming to non-dimensional form which in partial differential equations system. Since the boundary layer equations of viscoelastic fluid are an order higher than Newtonian (viscous) fluid, the adherence boundary conditions are insufficient to govern the solutions entirely. Hence, the augmentation of an extra boundary conditions is necessary to perform the computation. The computation is done by adopting the established procedures called Keller box method. The results are computed for velocity and microrotation distribution as well as skin friction coefficient. It is worth to mentioned at the special case, the present model can be deduced to the established model where the porosity, microinertia and magnetic term excluded. The output computed will be served as a reference to study the complex fluid especially when the fluid exhibit both viscous and elastic characteristics with microrotation effect

Oscillatory dissipative conjugate heat and mass transfer in chemically-reacting micropolar flow with wall couple stress : a finite element numerical study

High temperature non-Newtonian materials processing provides a stimulating area for process engineering simulation. Motivated by emerging applications in this area, the present article investigates the time-dependent free convective flow of a chemically-reacting micropolar fluid from a vertical plate oscillating in its own plane adjacent to a porous medium. Thermal radiative, viscous dissipation and wall couple stress effects are included. The Rosseland diffusion approximation is used to model uni-directional radiative heat flux in the energy equation. Darcy’s model is adopted to mimic porous medium drag force effects. The governing two-dimensional conservation equations are normalized with appropriate variables and transformed into a dimensionless, coupled, nonlinear system of partial differential equations under the assumption of low Reynolds number. The governing boundary value problem is then solved under physically viable boundary conditions numerically with a finite element method based on the weighted residual approach. Graphical illustrations for velocity, micro-rotation (angular velocity), temperature and concentration are obtained as functions of the emerging physical parameters i.e. thermal radiation, viscous dissipation, first order chemical reaction parameter etc. Furthermore, friction factor (skin friction), surface heat transfer and mass transfer rates have been tabulated quantitatively for selected thermo-physical parameters. A comparison with previously published paper is made to check the validity and accuracy of the present finite element solutions under some limiting cases and excellent agreement is attained. Additionally, a mesh independence study is conducted. The model is relevant to reactive polymeric materials processing simulation

Exact solutions of unsteady free convection flow of Casson, nano, and micropolar fluids over an oscillating vertical plate

Fluid-mechanics is an ancient science that is incredibly alive today. Therefore, the modern technologies require a deeper understanding of the behaviour of real fluids. Based on the relationship between shear stress and the rate of strain, fluids can be categorized as Newtonian fluids and non-Newtonian fluids. Various non- Newtonian fluid models have been used to investigate the behaviour of fluid motion, because of their universal nature. Solution corresponding to Newtonian and non- Newtonian fluids problem have received considerable attention due to their numerous applications in industries. This thesis is devoted to study the unsteady free convection flow of Newtonian fluid (nanofluids) and non-Newtonian fluids (Casson and micropolar fluids) over an oscillating vertical plate. Specifically, free convection flows of Casson fluids and micropolar fluids were studied with and without magnetohydrodynamic and porosity effects. Whereas studied in nanofluids also considered ramped wall temperature. Laplace transform was used to solve the partial differential equations governing the motion. The expressions of the obtained solutions for velocity, temperature and concentration were presented in simple forms. Skin friction, Nusselt number and Sherwood number were also calculated. The analytical results were plotted and discussed for magnetic, porosity, radiation, nanoparticle volume friction, Casson and microrotation parameters as well as Prandtl, Grashof and modified Grashof numbers. For Casson fluid, it was observed that velocity decreases with increasing values of Casson parameter as Casson fluid exhibits yield stress. In case of nanofluids, it was found that fluid velocity was greater for isothermal temperature as compared to ramped wall temperature of the plate. However, for micropolar fluid, microrotations increases near the plate and decreases far away from the plate due to an increase in viscosity parameter. The results showed that for long time interval, the oscillations have similar amplitudes and phase shift that persists for all times. For verification, the obtained solutions were recovered as special cases. The existing solutions in the literature were also reduced to their limiting cases of the present results. The exact solutions obtained in this thesis serve as a benchmark to verify approximate methods, whether asymptotic, experimental or numerical