Numerical Analysis of Turbulent Wakes of Turbomachinery Rotor Blades

1980 ◽  
Vol 102 (4) ◽  
pp. 462-472 ◽  
Author(s):  
C. Hah ◽  
B. Lakshminarayana
Keyword(s):  
Numerical Analysis ◽  
Three Dimensional ◽  
Reynolds Stress Model ◽  
Rotor Blades ◽  
Turbulence Closure ◽  
Turbulence Structure ◽  
Closure Model ◽  
Mean Velocity ◽  
Turbulence Closure Model ◽  
The Mean

The wakes of turbomachinery rotor blades are turbulent, three-dimensional, and are subjected to curvature and rotation effects. The objective of this study is to predict the development of such wakes and compare the predictions with the existing data. A finite difference procedure is employed in the numerical analysis of the wake utilizing the continuity, momentum, and turbulence closure equations in the rotating curvilinear and non-orthogonal coordinate system. The turbulence closure is affected by the modified Reynolds stress model. The effects of curvature and rotation on the turbulence structure are accounted for with this turbulence closure model. The pedictions from the present turbulence model agree well with the mean velocity and the turbulence wake data.

Comparison of a Nonlinear k-ε Turbulence Closure Model With Stress Transport Models

1993 ◽  
Author(s):  
Muhammad A. R. Sharif ◽  
Yat-Kit E. Wong
Keyword(s):  
Pipe Flow ◽  
Flow Problem ◽  
Swirling Flow ◽  
Transport Model ◽  
Turbulent Pipe Flow ◽  
Turbulence Closure ◽  
Closure Model ◽  
Transport Models ◽  
Mean Velocity ◽  
Turbulence Closure Model

Abstract The performance of a nonlinear k-ϵ turbulence closure model (NKEM), in the prediction of isothermal incompressible turbulent flows, is compared with that of the stress transport models such as the differential Reynolds stress transport model (RSTM) and the algebraic stress transport model (ASTM). Fully developed turbulent pipe flow and confined turbulent swirling flow with a central non-swirling jet are numerically predicted using the Marker and Cell (MAC) finite difference method. Comparison of the prediction with the experiment show that all three models perform reasonably well for the pipe flow problem. For the swirling flow problem, the RSTM and ASTM is superior than the NKEM. RSTM and ASTM provide good agreement with measured mean velocity profiles. However, the turbulent stresses are over- or under-predicted. NKEM performs badly in prediction of mean velocity as well as the turbulent stresses.

scholarly journals Prediction of flow and dispersion in cross–ventilated buildings

2019 ◽  
Vol 128 ◽  
pp. 05002
Author(s):  
Ali Cemal Benim ◽  
Michael Diederich ◽  
Ali Nahavandi
Keyword(s):  
Computational Analysis ◽  
Turbulence Models ◽  
Reynolds Stress Model ◽  
Turbulence Structure ◽  
Detached Eddy Simulation ◽  
Mean Velocity ◽  
Eddy Simulation ◽  
Large Eddy ◽  
The Mean ◽  
Grid Independence

The present paper presents a detailed computational analysis of flow and dispersion in a generic isolated single–zone buildings. First, a grid generation strategy is discussed, that is inspired by a previous computational analysis and a grid independence study. Different turbulence models are appliedincluding two-equation turbulence models, the differential Reynolds Stress Model, Detached Eddy Simulation and Zonal Large Eddy Simulation. The mean velocity and concentration fields are calculated and compared with the measurements. A satisfactory agreement with the experiments is not observed by any of the modelling approaches, indicating the highly demanding flow and turbulence structure of the problem.

Flow Structure Issued from a Bent Chimney around a Cylindrical Obstacle: Effect of the Aspect Ratio

2011 ◽  
Vol 312-315 ◽  
pp. 965-970 ◽  
Author(s):  
Inès Bhouri Baouab ◽  
Nejla Mahjoub Said ◽  
Hatem Mhiri ◽  
Georges Le Palec ◽  
Philippe Bournot
Keyword(s):  
Numerical Study ◽  
Three Dimensional ◽  
Reynolds Stress Model ◽  
Stress Model ◽  
Closure Model ◽  
Turbulence Closure Model ◽  
Cylindrical Obstacle ◽  
Recirculation Zones ◽  
Obstacle Effect ◽  
Pollutants Dispersion

We present in this work a numerical study of pollutants’ dispersion resulting from a bent chimney around a cylindrical obstacle. A three-dimensional numerical model, based upon the RSM (Reynolds Stress Model) turbulence closure model was used. The adopted grid is not uniform, particularly refined near the chimney and around the cylindrical building. The domain is large enough to be able to visualize the recirculation zones and the vortices created by the building. The results obtained in three dimensional configurations make possible the description of the dynamics and mass features under different aspect rations.

Numerical Simulation on the TIBL Structure in Shoreline Areas with a 2D Higher-Order Turbulence Closure Model

1995 ◽  
Vol 34 (2) ◽  
pp. 520-527
Author(s):  
Jiang Weimei ◽  
Wu Xiaoming ◽  
Zhou Jingnan
Keyword(s):  
Numerical Simulation ◽  
Internal Boundary Layer ◽  
Higher Order ◽  
Turbulence Closure ◽  
Internal Boundary ◽  
Initial Condition ◽  
Closure Model ◽  
Thermal Internal Boundary Layer ◽  
Turbulence Closure Model ◽  
The Mean

Abstract A 2D higher-order turbulence closure model for research on the structure of the thermal internal boundary layer (TIBL) has been developed in this paper. The mean quantities (temperature and wind), as well as their turbulent moments and their distribution under the TIBL, were computed. Results of numerical simulation show that under the initial condition of onshore flow and surface temperature on land being higher, than on water. 1) the profile of the TIBL on shore can be identified by the distributions of the mean wind and temperature, and during the integration hours there is an unstable stratified region over land that extends upward and inland gradually; 2) the shape of the profiles of the TIBL is roughly in concordance with observed profiles, but there are some differences, obviously, between the results computed by the formula of h ∼ x1/2 and the results of the numerical experiment; and 3) u′2, v′2, w′2, and u′w′, θ′w′ and their general features are well reproduced by the model. It is shown that the numerical model is feasible and effective.

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