جستجوی مقالات مرتبط با کلیدواژه "driven cavity" در نشریات گروه "مکانیک"

The cavity problem always has been considered as a classic and fundamental problem. Specific materials like Bingham viscoplastic which is sort of Non-newtonian fluids shows resistance in a certain range of stress, calling yield stress, and almost acts like rigid body in this limited area. In case of increase applied stress, flows like fluid. Considering heat transfer in this type of material and investigate it, yield stress and viscosity variations with temperature as in practice we face will not be far-fetched. In the present work the numerical solution of the problem of Bingham material inside lid-driven cavity, investigating fluid flow and heat transfer in view of the changes in material properties has been done and results have shown with change in dimensionless numbers and parameters of Re=10-1000, Bn=1-2000, Pr=0.01-100 and E=5000-50000. In this study, using the finite volume method to discretize governing equations and the use of collocated grid, effect of viscosity and yield stress dependence to temperature compared with independence mode and then distribution of horizontal and vertical components of velocity, yield areas and flow inside cavity, center of vortex and then heat transfer due to the stream lines next to side walls, have been analyzed.

This study presents a numerical investigation for laminar mixed convection flow of radiating gases in an inclined lid-driven cavity. The fluid is treated as a gray, absorbing, emitting and scattering medium. The governing differential equations consisting the continuity, momentum and energy are solved numerically by the computational fluid dynamics (CFD) techniques to obtain the velocity and temperature fields. Discretized forms of these equations are obtained by the finite volume method and solved using the SIMPLE algorithm. Since the gas is considered as a radiating medium, besides convection and conduction, radiative heat transfer also takes place in the gas flow. For computation of the radiative term in the gas energy equation, the radiative transfer equation (RTE) is solved numerically by the discrete ordinate method (DOM). The effect of lid driven speed, on the thermohydrodynamic behavior of two-dimensional cavity is carried out. Results are shown as contours of isotherms, streamlines and distributions of convective and total Nusselt numbers along the bottom wall of cavity. It is revealed that increasing in Reynolds number causes almost uniform temperature distribution in cavity, especially for 30° and 60° inclination angles.

Taguchi method since 1980 is used as an effective way to optimize the design process engineering tests. In this paper by using of taguchi method optimal conditions of the mixed convection and entropy generation in a square cavity filled with Cu-water nanofluid is analyzed. For this purpose a L16 (43) orthogonal taguchi array is used. Discretization of the governing equations were achieved through a finite volume method and solved with SIMPLE algorithm. The effect of Richardson number (0.1-100), the volume fraction of copper nanoparticles (0-10%) and the wavelength of the wavy surface (0- 1) as an effective parameters for analyzing in four levels are considered. This analysis was performed for fixed Grashof number 104. The results show that the mean Nusselt number decreases by increase of the Richardson number, the volume fraction of nanoparticles and the wavelength of the wavy surface. It is found that the Flat plate (for wavy surface with the wavelength 0) and the volume fraction 0% in the Richardson number 0.1 is optimal design for heat transfer while the geometry with Ф=5%, Ri=100 and λ=0.25 is optimal design for entropy generation. Finally for maximum heat transfer and minimum entropy generation the geometry with Ф=0%, Ri =1 and λ=0.25 can be considered as an optimal design.

In this study, the effects of strength and direction of a magnetic field on lid-driven cavity flow in a wide range of magnetic field strength variations (0 to 10 Tesla) are studied. The governing equations, including conservative equations of momentum, continuity and magnetic field were solved numerically. Momentum and continuity were solved by the finite volume method, using SIMPLE algorithm where the finite difference method was used for solving of magnetic field equation. In this research, the effects of magnetic field on the velocity distribution, streamlines, and vortex flow shows that the vortices of the cavity shrink up to 0.01 Tesla, where the uniform and vertical magnetic field was applied from the bottom surface. For the magnetic field of 0.01 Tesla, the vortices disappear. Higher values of magnetic field create larger vortices.

To investigate the mixed convection flows through nano-fluid in a square double lid-driven cavity with various inclination angles, a numerical method based on the finite volume approach is applied. In This paper Sio2/water nano-fluid have been used. The cavity is un-uniformly heated from the left, Th, and cooled from the opposite wall;the top and the bottom moving walls have been supposed to be insulated. The study has been executed for the Richardson number 0.1 to 10, Reynolds number 1 to 100 while solid volume fraction (φ) of nano-particles altered from 0 to 0.06. The impact of angle of inclination, solid volume fraction of nano-fluids, velocity of moving walls and Richardson number on hydrodynamic and thermal characteristics have been studied and discussed. As a result, it was found that the heat transfer increase with increase in solid volume fraction for a particular Reynolds.Also in higher Richardson, the effect of solid volume fraction increases on thermal behavior and flow pattern.