Effects of Soret, Dufour, chemical reaction, thermal radiation and volumentric heat generation/absorption on mixed convection stagnation point flow on an Iso-thermal vertical plate in porous media

A mathematical model is analyzed in order to study the effects of Soret, Dufour, chemical reaction, thermal radiation and volumentric heat generation/absorption on mixed convection stagnation point flow on an Iso-thermal vertical plate in a porous media. The governing partial differential equations are transformed into set of coupled ordinary differential equations, which are solved numerically using Runge-Kutta sixth order method along with shooting technique. The physical interpretation to this expression is assigned through graphs and tables for the wall shear stress , Nusselt number and Sherwood number . Results were compared with the existing literature and showed a perfect agreement. Similarly, results showed that the fields were influenced appreciably by the effects of the governing parameters: Soret number Sr, Dufour number Df, chemical reaction parameter γ, thermal radiation parameter Ra, order of reactions n, thermal Grashof number GT, solutal Grashof number GC, Prandtl number Pr, permeability parameter K, rate of heat generation/absorption parameter S, and magnetic field strength parameter M. It was evident that for some kind of mixtures such as the light and medium molecular weight, the Soret and Dufour’s effects should be considered as well

THE ROLE OF TECHNOLOGY IN THE BUILT ENVIRONMENT

Lately, the built environment has been witnessing a lot of hazards ranging from collapsed buildings and bridges, floods and typhoons, droughts and landslides, as well as fire, tsunamis, hurricanes and earthquakes. Others are hazards launched through technology such as bio-terrorism and cyber-terrorism. Thus, necessity is place on Architecture, Engineering and Construction (AEC) industry to prevent the "sick building" syndrome and make the built environment safe, secure, and healthy for mankind. This paper attempts to examine the immediate and remote causes of fail and sick buildings with a view to proffering solutions through the use of technology. Furthermore, the paper presents the application of the available technologies such as e-construction, Geographical Information System (GIS), Computer Aided Design (CAD) and the Global Positioning System (CPS) to the built environment. An integrated design environment within the AEC industry is proposed to allow for modeling, designing, analyzing, and visualizing structures. Thus, the behaviour of structures can be modeled through "virtual reality", leading to the creation of "smart buildings", which are design concepts for this generation

Effects of internal heat generation, thermal radiation, and buoyancy force on boundary layer over a vertical plate with a convective boundary condition

In this paper we analyze the effects of internal heat generation, thermal radiation, and buoyancy force on the laminar boundary layer about a vertical plate in a uniform stream of fluid under a convective surface boundary condition. In the analysis, we assumed that left surface of the plate is in contact with a hot fluid while a stream of cold fluid flows steadily over the right surface with a heat source that decays exponentially. Similarity variable method is applied to the governing non-linear partial differential equations. The transformed into a set of coupled nonlinear ordinary differential equations are solved numerically by applying shooting iteration technique together with fourth order Runge-Kutta integration scheme. The effects of Prandtl number, local Biot number, the internal heat generation parameter, thermal radiation, and the local Grashof number on the velocity and temperature profiles are illustrated and interpreted in physical terms. A comparison with previously published results in special case of the problem shows an excellent agreement

Finite Difference Dynamic Analysis of Railway Bridges Supported by Pasternak Foundation under Uniform Partially Distributed Moving Railway Vehicle

Rail transport has experienced great advances in recent times, characterised by increasing high speed and weights of railway vehicles. The vibration and dynamic stress being subjected to by the transport structures, such as road or railway bridges, have increased due to these factors. In this paper, the dynamic response of railway bridges, modelled as an elastic rectangular plate, continuously supported by Pasternak foundation and traversed by moving railway vehicle is investigated. Finite difference method is used to transform the set of coupled partial differential equations to a set of algebraic equations. The desired solutions are obtained with the aid of computer programs developed in conjunction with MATLAB. It is observed that the deflection of the railway bridge decreases as the foundation moduli increase. The rotatory inertia and shear deformation have significant effect on the deflection of the railway bridge under a moving railway vehicle (modelled as partially distributed moving load)

Dynamic Behaviour of a Double Rayleigh Beam-System Due to Uniform Partially Distributed Moving Load

This paper deals with the dynamic behavior of a double-beam system traversed by a uniform partially distributed moving load. The system is composed of two identical parallel homogeneous simply-supported uniform Rayleigh beams of equal lengths which are continuously connected by a viscoelastic core. The forced vibration problem is solved by the application of the finite Fourier and Laplace integral transformations. Using a numerical example, various plots of the deflections of the beams are presented and discussed for different values of the speed, rotatory inertia and fixed length of the load

Radiation and viscous dissipation effects for the Blasius and Sakiadis flows with a convective surface boundary condition

This study is devoted to investigate the radiation and viscous dissipation effects on the laminar boundary layer about a flat-plate in a uniform stream of fluid (Blasius flow), and about a moving plate in a quiescent ambient fluid (Sakiadis flow) both under a convective surface boundary condition. Using a similarity variable, the governing nonlinear partial differential equations have been transformed into a set of coupled nonlinear ordinary differential equations, which are solved numerically by using shooting technique along side with the sixth order of Runge-Kutta integration scheme and the variations of dimensionless surface temperature and fluid-solid interface characteristics for different values of Prandtl number Pr, radiation parameter NR, parameter a and the Eckert number Ec, which characterizes our convection processes are graphed and tabulated. Quite different and interesting behaviours were encountered for Blasius flow compared with a Sakiadis flow. A comparison with previously published results on special cases of the problem shows excellent agreement

Multiplicity of Solutions for a Reactive Variable Viscous Couette Flow under Arrhenius Kinetics

This paper investigates the properties of solution for a reactive temperature dependent viscous Couette flow through parallel plates with non-uniform temperature. We showed that the problem has two distinct solutions and the solution breaks down for some values of the Frank-kameneskii parameter. Effect of various parameters in the model are presented and discussed. Keywords: Arrhenius kinetics, Couette flow, variable viscosity, Bratu-type equatio

Dynamic Analysis of Railway Bridges Supported by Winkler Foundation under Uniform Partially Distributed Moving Railway Vehicle

Transport structure such as railway bridges (plates), are subjected to moving railway vehicles (loads) which vary in both space and time. This branch of transport has experienced great advances, characterised by increasing high speed and weights of railway vehicles. Structures and media on which the railway vehicles move have, therefore, been subjected to vibration and dynamic stress more than ever before. The motivation for this paper is the observation that most of the works available in the literature are concerned with plates for which the effects of both rotatory inertia and shear deformation are neglected. Also the plates are assumed not resting on any foundation. In this paper, the dynamic response of railway track, modelled as an elastic rectangular plate, continuously supported by an elastic foundation and traversed by moving railway vehicle is investigated. Finite difference method is used to transform the set of coupled partial differential equations to a set of algebraic equations. The desired solutions are obtained with the aid of computer programs developed in conjunction with MATLAB. This shows that the elastic foundation, rotatory inertia and shear deformation have significant effect on the dynamic response of the railway bridge, to the moving railway vehicle (modelled as partially distributed moving load). In particular, it is observed that the deflection of the railway bridge decreases as the foundation moduli increas

Dynamic Response of Mindlin Elastic Plate Supported by Pasternak Foundation under Uniform Partially Distributed Moving Load

Various transport structures, ranging from railways, roads and bridges to space vehicles and submarines, are usually subjected to moving loads which vary in both space and time. All branches of transport have experienced great advances, characterised by increasing high speed and weights of railway vehicles. Structures and media on which the railway vehicles move have, therefore, been subjected to vibration and dynamic stress more than ever before. The motivation for this paper is from the observation that most of the works available in the literature are concerned with plates for which the effects of both rotatory inertia and shear deformation are neglected. Also the plates are assumed not resting on any foundation. In this paper, the dynamic response of Mindlin plate, continuously supported by Pasternak foundation and traversed by moving load is investigated. Finite difference method is used to transform the set of coupled partial differential equations to a set of algebraic equations. The desired solutions are obtained with the aid of computer programs developed in conjunction with MATLAB. This shows that the elastic foundation, rotatory inertia and shear deformation have significant effect on the dynamic response of the plate, to the moving load. In particular, it is observed that the deflection of the plate decreases as the foundation moduli increas

A Comparison of Dynamic Behaviours of Mindlin, Shear, Rotatory and Kirchoff Plates Supported by Subgrade under Moving Load

Various Plates and Plate-like transport structures, such as roads, railway bridges, space vehicles and submarines, are usually subjected to different types of loads. These loads include cars, Railway vehicles and human beings. In this paper we made an attempt to analyse the dynamic responses of some specific plates to moving load. Four types of plates were considered, namely: Mindlin plate, Shear plate, Rotatory plate and Kirchoff plate. The moving load is assumed to be uniform partially distributed, while the plates are isotropic and supported by Winkler foundation. Finite difference technique was used to transform the set of dimensionless first order partial differential equations to a set of algebraic equations. Computer programs were developed and used in conjunction with MATLAB in order to obtain the desired solution. It was observed that the solution obtained were consistent with the ones in literature. Specifically, it was observed that for fixed values of velocity, contact area and foundation constant, the values of the maximum deflection are higher for Mindlin plates when compared to shear, rotatory and Kirchoff plates