Lokendra Kumar

Finite element solution of mixed convection micropolar flow driven by a porous stretching sheet

This paper presents a finite element solution for the mixed convection micropolar flow driven by a porous stretching sheet with uniform suction. The governing partial differential equations are solved numerically by the using finite element method and the results have been compared with those obtained by using the quasi-linearization method. The effect of surface conditions on the velocity, microrotation as well as for temperature functions has been studied. It is noticed that the micropolar fluids help in the reduction of drag forces and also act as a cooling agent.

Numerical solution of free convection MHD micropolar fluid flow between two parallel porous vertical plates

The fully developed electrically conducting micropolar fluid flow between two vertical porous parallel plates is studied in the presence of temperature dependent heat sources including the effect of frictional heating and in the presence of a magnetic field. Profiles for velocity, microrotation and temperature are presented for a wide range of Hartmann numbers and the micropolar parameter. The skin friction, couple stress and Nusselt numbers at the plates are shown in the tables.

Finite-element simulation of mixed convection flow of micropolar fluid over a shrinking sheet with thermal radiation

An analysis is carried out to investigate the effect of thermal radiation on mixed convection flow of a msicropolar fluid over a shrinking sheet with prescribed surface heat flux. The velocity of the shrinking sheet and the surface heat flux are assumed to vary as a linear function of the distance from the origin. Using the boundary layer approximation and similarity transformations, the governing partial differential equations are transformed into a system of nonlinear coupled ordinary differential equations which are solved numerically by using a variational finite element method. The effects of suction, radiation, and buoyancy parameters on velocity, microrotation, and temperature functions are examined in detail. The skin-friction coefficient, local couple stress, and the local Nusselt number have also been computed. Under special conditions, an analytical solution is obtained only for the flow velocity, which is compared with the numerical results obtained by finite element method. An excellent agreement of the two sets of solutions is observed, which confirms the validity of the finite element method employed herein. Also, in order to check the convergence of numerical solutions, the calculations are executed by reducing the mesh size. The sensitivity of the solution as a function of suction through the permeable sheet has also been examined. The current study has important applications in industrial polymeric materials processing.

Finite Element Solution of Unsteady Mixed Convection Flow of Micropolar Fluid over a Porous Shrinking Sheet

The objective of this investigation is to analyze the effect of unsteadiness on the mixed convection boundary layer flow of micropolar fluid over a permeable shrinking sheet in the presence of viscous dissipation. At the sheet a variable distribution of suction is assumed. The unsteadiness in the flow and temperature fields is caused by the time dependence of the shrinking velocity and surface temperature. With the aid of similarity transformations, the governing partial differential equations are transformed into a set of nonlinear ordinary differential equations, which are solved numerically, using variational finite element method. The influence of important physical parameters, namely, suction parameter, unsteadiness parameter, buoyancy parameter and Eckert number on the velocity, microrotation, and temperature functions is investigated and analyzed with the help of their graphical representations. Additionally skin friction and the rate of heat transfer have also been computed. Under special conditions, an exact solution for the flow velocity is compared with the numerical results obtained by finite element method. An excellent agreement is observed for the two sets of solutions. Furthermore, to verify the convergence of numerical results, calculations are conducted with increasing number of elements.

Finite element study of mixed convection micropolar flow in a vertical circular pipe with variable surface conditions

In the present paper the problem of fully developed mixed convection flow of a micropolar fluid with heat sources, in a vertical circular pipe has been studied. The governing non-linear coupled differential equations are solved by using the finite element technique. The effect of the micropolar parameter, heat source parameter, surface parameter and dissipation parameter on the velocity, micro-rotation and temperature functions have been discussed. The heat sources increase the velocity and temperature in the pipe while the heat sinks decrease them. The micropolar fluid thus behaves as a coolant and such a type of flow has useful applications in combustion chambers, exhaust nozzles of porous walled flow reactors, and the design of chemical processing equipment.

Human Gait Recognition Based on Dynamic and Static Features Using Generalized Regression Neural Network

Biometric Recognition using the behavioral modality of gait is an emerging research area. This paper describes a method for human gait recognition using Generalized Regression Neural Networks. The feature space is composed of a combination of dynamic (time-varying) gait signals and static body-shape parameters, extracted from binary silhouettes obtained after background subtraction from human gait sequences. The inputs to the neural network are obtained by performing Discrete Cosine Transform (DCT) on the feature space, followed by selection of transformed coefficients to construct compact vectors.

Dual Solutions in MHD Boundary Layer Nanofluid Flow and Heat Transfer with Heat Source/Sink considering Viscous Dissipation

In this present analysis, the numerical investigation of steady, magneto-hydrodynamic boundary-layer nanofluid past a permeable shrinking sheet has been discussed considering Brownian motion and thermophoresis. The effect of viscous dissipation, heat source/sink and suction/injection are taken into account and controlled by the non-dimensional parameters. After using appropriate similarity transformation, the final system of ordinary differential equation is solved numerically by shooting technique. The dual solutions exist for whereas unique solution is obtained at critical values and solution does not exist for for other fixed parameters. The current study shows that the effect of nonlinear parameter, Hartmann number and heat source/sink on skin friction and rate of heat transfer. The results are validated for the limiting cases.

Finite Element Analysis of MHD Flow of Micropolar Fluid over a Shrinking Sheet with a Convective Surface Boundary Condition

This paper presents a numerical solution for the steady mixed convection magnetohydrodynamic (MHD) flow of an electrically conducting micropolar fluid over a porous shrinking sheet. The velocity of shrinking sheet and magnetic field are assumed to vary as power functions of the distance from the origin. A convective boundary condition is used rather than the customary conditions for temperature, i.e., constant surface temperature or constant heat flux. With the aid of similarity transformations, the governing partial differential equations are transformed into a system of nonlinear ordinary differential equations, which are solved numerically, using the variational finite element method (FEM). The influence of various emerging thermophysical parameters, namely suction parameter, convective heat transfer parameter, magnetic parameter and power index on velocity, microrotation and temperature functions is studied extensively and is shown graphically. Additionally the skin friction and rate of heat transfer, which provide an estimate of the surface shear stress and the rate of cooling of the surface, respectively, have also been computed for these parameters. Under the limiting case an analytical solution of the flow velocity is compared with the present numerical results. An excellent agreement between the two sets of solutions is observed. Also, in order to check the convergence of numerical solution, the calculations are carried out by reducing the mesh size. The present study finds applications in materials processing and demonstrates excellent stability and convergence characteristics for the variational FEM code.

Numerical study of steady dissipative mixed convection optically-thick micropolar flow with thermal radiation effects

The objective of this paper is to study theoretically and numerically the effect of thermal radiation on mixed convection boundary layer flow of a dissipative micropolar non-Newtonian fluid from a continuously moving vertical porous sheet. The governing partial differential equations are transformed into a set of non-linear differential equations by using similarity transformations. These equations are solved iteratively with the Bellman-Kalaba quasi-linearization algorithm. This method converges quadratically and the solution is valid for a large range of parameters. The effects of transpiration (suction or injection) parameter, buoyancy parameter, radiation parameter and Eckert number on velocity, microrotation and temperature functions have been studied. Under a special case comparison of the present numerical results is made with the results available in the literature and an excellent agreement is found. Additionally skin friction and rate of heat transfer have also been computed. The study has appli...

Effect of Uncertainties in Physical Properties on Mixed Convection Along a Rotating Vertical Slender Cylinder With Nanofluids

The present investigation is aimed to study the effects of uncertainties in physical properties on predicting mixed convection alumina-water nanofluid flow and heat transfer characteristics along a rotating vertical slender cylinder. For this purpose, the different models for thermal conductivity and dynamic viscosity which takes into account the effects of particle size, particle volume fraction, nanolayer conductivity and temperature on the steady boundary layer are applied. The transformed set of coupled non-linear partial differential equations for the single phase nanofluid model is solved by robust Finite Element Method. The influence of various pertinent parameters on velocity profile, temperature profile and on Nusselt number are shown graphically. Excellent validation of the present numerical results has been achieved with earlier published results. It is also found that the Nusselt number increases nonlinearly with the increase of nanoparticle loading for the KKL model which correlates strongly with experimental findings.Copyright