Papers by Keyword: Three-Dimensional Flow

Abstract: In this study, we numerically investigate the hydromagnetic three dimensional flow of a radiating Maxwell fluid over a stretching sheet embedded in a porous medium with heat source/sink, first ordered chemical reaction and Soret effect. The corresponding boundary layer equations are reduced into set of non-linear ordinary differential equations by means of similarity transformations. The resulting coupled non-linear equations are solved numerically by employing boundary value problem default solver in MATLAB bvp4c package. The obtained results are presented and discussed through graphs and tables. It is noticed that the Deborah number reduces the velocity fields and improves the temperature and concentration fields. Nomenclature

Abstract: In this study we examined the entropy generation in the three-dimensional flow of nanofluid with graphene nanoparticles. Viscous heating function is added in the energy equation to study fluid frictional effects on entropy generation. The modeled equations are converted into ordinary differential equations using appropriate dimensionless quantities. Shooting technique is implemented to acquire numerical solutions. The numerical solutions are also obtained by using Matlab built-in boundary value solver bvp4c for the validation of our numerical code. The obtained results reveal that they are in good correlation. The obtained numerical results are represented by various graphs and illustrated in great detail.

Abstract: Using a multiscale model based on the variable interval time average method and a set of averaged equations for incompressible turbulent flows, we simulate the three-dimensional separated and reattaching flow over a swept backward-facing step. The results show that the reattachment length and vortex structure vary with the swept angles from 15° to 60° through a detailed study about velocity profile and pressure distribution. Generally the reattachment length and span wise vorticity decrease dramatically after =30°. The result fully accord with experimental data. Results show that this model is suitable for separated flows, and accurately predict the flow field, so this model should be useful in engineering application.

Abstract: The flow around two vertical cylindrical piles exposed to a steady current is studied numerically by a three-dimensional hydrodynamic model, which is closured with a k-ε turbulence model. This model is firstly validated by experimental data obtained from a labortory experiment for a steady flow through a circular pile. Then this validated model is used to study flow pattern around two cylindrical piles. Finally, four key physical factors of the size of the horseshoe vortex and lee wake vortex, the maximum current velocity and bottom shear stress are analyzed under the different pile spaces. The main conclusions are: i) the size of the horseshoe vortex increases with the increase of the two pile space, while the size of the lee wake vortex changes slightly; ii) the maximum current velocity and the maximum bottom shear stress decrease with the increase of two pile space, and reach steady after the two pile space larger than six times of cylindrical pile diameter.

Abstract: The purpose of this work is to study the fluid flow regimes in a porous media with high enough velocities (in the range of laminar flow). In our study, the results obtained from expanding Darcy’s equation to Forchheimer’s equation with volume averaging method have been used for studdying the fluid flow behavior in 2D and 3D models. Results of numerical simulations show that in all cases, there are weak inertial regime, strong inertial regime and transition zone. In all the cases, the domain of weak inertial regime is relatively narrow, and this problem is intensified in the 3D numerical simulations. This could be the reason of missing the weak inertial regime in experimental studies on inertial fluid flow in porous media. The domain of strong inertial regime in 3D models is so wide that after Darcy’s regime, the governed regime is the strong inertial regime. To obtain more accurate and analytical results, more studies should be done on the 2D and the 3D flow regimes.

Abstract: Numerical predictions are carried out in order to investigate the fractured horizontal well behaviour. A control volume based approach is used to solve the transient 3D diffusivity equation adopting an irregular hybrid grid. Effect of several parameters such as reservoir characteristics, fracture properties and physical and geometrical parameters of the reservoir and the well that may affect the well productivity and production are discussed. Simulation results allow to predict the optimum number of induced fractures.