In the current study, reduction of nitrogen oxide from exhaust gas in the presence of NH3 as reductant on selective catalytic reductant (SCR) impregnated catalytic converter was simulated using Comsol© software. Mass transfer (one-dimensional) and heat transfer (three-dimensional) governing equations were taken into account to model the unsteady state behavior of the catalytic converter. Modeli...

In this paper a numerical method is used to study the unsteady state natural convection heat transfer within a confined porous media with uniform internal heat generation. The governing equations based on the Darcy model and Bossiness approximations are solved, using the finite difference Alternating Direction Implicit (ADI) method. The developed program was used to simulate natural convection ...

excessive withdrawal of groundwater and reduced rainfall in recent years have caused the drawdown of groundwater table. therefore, it is necessary to manage it for preventing its damage. the present study was carried out to investigate the effect of increasing the irrigation efficiency on groundwater fluctuation on ajab-shir plain aquifer. the aquifer was simulated by using visual modflow 3.1 s...

Caruachi Hydroelectric Project conforms together with Guri, Tocoma and, Macagua the Lower Caroni Hydroelectric Development. Second Stage of River Diversion at Caruachi included diverting the Caroni River through 18, 5.5 × 9m sluices in the spillway lower body that after being closed by gates permitted the reservoir filling. In order to define the precise timing for closure of the sluices and to...

A potential flow model is used to study the unsteady flow past two airfoils in configuration, each of which is suddenly set into motion. The airfoil bound vortices are modeled using lumped vortex elements and the wake behind the airfoil is modeled by discrete vortices. This consists of solving a steady state flow problem at each time-step where unsteadiness is incorporated through the “zero nor...

This paper presents an adjoint method for the optimal control of unsteady flows. The goal is to develop the continuous and discrete unsteady adjoint equations and their corresponding boundary conditions for the timeaccuratemethod. First, this paper presents the complete formulation of the time-dependent optimal design problem. Second, we present the time-accurate unsteady continuous and discret...

The work presents an artificial compressibility method applied to incompressible Navier-Stokes equations for steady as well as for unsteady flows. Two modifications of unsteady numerical solution by an implicit finite volume method are considered. First one uses large artificial compressibility parameter and the iterative solution approximates unsteady evolution of flow. The second approach int...

In this paper, we study the steady and unsteady magneto hydro dynamic (MHD) viscous, incompressible free and forced convective flow of an electrically conducting Newtonian fluid through a porous medium in the presence of appreciable thermal radiation heat transfer and surface temperature oscillation taking hall current into account. The fluid is assumed to be optically-thin and magnetic Reynold...