TVET
M.J. Maghrebi; A. Zarghami; M. Feyzabadi Farahani
Abstract
The non-dimensional Navier stokes equations in rotational form for the boundary layer flow are solved using direct numerical simulation. The length scale and velocity scale of the base flow the boundary layer thickness and the inviscid velocity outside the layer are used as the length and velocity scales ...
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The non-dimensional Navier stokes equations in rotational form for the boundary layer flow are solved using direct numerical simulation. The length scale and velocity scale of the base flow the boundary layer thickness and the inviscid velocity outside the layer are used as the length and velocity scales at the inlet boundary of the computational domain are used as two characteristics to define the flow Reynolds number. The governing equations are discritised in the streamwise direction using a sixth order compact finite difference scheme, and in the cross-direction using a mapped compact finite difference scheme. An algebraic mapping is used to map the physical domain into the computational domain .The compact third order of Runge-kutta method is used for the time-advancement purpose. The convective outflow boundary condition is employed to create a non-reflective type boundary condition at the outlet. The simulation results of this flow were compared by Blasius solution that show accuracy program. In this study, also, characteristics of laminar boundary layer flow verification for accuracy program with divided the lengths and velocity by length of plane and uniform velocity of environment respectively. Profiles and contours of velocity and vorticity have planed in flow arrow and self- similar have seen.
M.J. Maghrebi; A. Zarghami; M. Feyzabadi Farahani
Abstract
The dimensionless Navier-Stokes equation is solved in a rotational form for the flow of a two-dimensional boundary layer of plates by a direct numerical method. Considering the speed profile at the input of the computational domain, the thickness of the boundary layer has been used as the characteristic ...
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The dimensionless Navier-Stokes equation is solved in a rotational form for the flow of a two-dimensional boundary layer of plates by a direct numerical method. Considering the speed profile at the input of the computational domain, the thickness of the boundary layer has been used as the characteristic length and the uniform velocity of the environment has been used as the characteristic velocity for dimensionlessness. The governing differential equations are broken down using the method of finite compression difference in the main directions of the flow and perpendicular to the flow. A forced mapping has been used to convert the physical domain to the computational domain. In order to develop the calculations in the time domain, the third-order compact Ranj Kota method has been used. The output boundary condition is determined using the transfer model. The simulation results of this type of flow are compared with the resolution of Blasius, which shows the accuracy of the code. In this study, the flow characteristics of the quiet boundary layer to evaluate the accuracy of the code, test and by dividing the lengths and velocities by the thickness of the boundary layer and the uniform velocity of the environment, profiles and contours of velocity and vortex in the device of dimensionless coordinates and self-similarity have seen.
science education
M.J. Maghrebi; M. Feyzabadi Farahani; A. Zarghami
Abstract
Theories of linear stability, reinforcement, or degradation of small disturbances examine the velocity applied to the average velocity of the flow. When the boundary layer flow expands linearly in the early stages of its development, the input boundary conditions of the computational domain are determined ...
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Theories of linear stability, reinforcement, or degradation of small disturbances examine the velocity applied to the average velocity of the flow. When the boundary layer flow expands linearly in the early stages of its development, the input boundary conditions of the computational domain are determined using the results of the linear stability solution. In order to better adapt to laboratory results, spatial stability analysis is used. Using an algebraic mapping, the physical domain is converted to a computational domain. To solve the Or-Samerfeld equation, a spectral method has been used that has led to the solution of a special value problem. Comparing laboratory results and results of spatial and temporal perturbation stability analysis, it can be stated that spatial perturbation growth analysis more accurately describes the instability characteristics of the perturbation boundary flow. Small frequencies are much more accurate.
