ln the paper a numerical program package is described to calculate incompressible, unsteady, three-dimensional, viscous and turbulent flow fields around sharp edged obstacle. By this the velocity and pressure distributions in the flow field and on the surfaces of square-formed bodies in a plane channel can be determined, as well as the frequencies of periodic vortex separations The channel consists of two plates extended to infinity. On the lower plate the square-formed body, which is identical with the building model, is placed.
This paper investigates the role of turbulence models in numerical calculations of flow over obstacles with second-moment closure models. Two models for the pressure-strain correlations are examined in the study. Computations of the main characteristics of the mean flow and the turbulent fields are compared against experimental data, and results obtained with the standard k-e model. All models give reasonable agreement with the data.
Flowfields around bluff bodies are characterized by complex distributions of the strain-rate tensor. Such flowfields can be analyzed with various turbulence models. The shortcoming of the eddy viscosity modelling in the k-e model is scrutinized in comparison with the results of ASM. The accuracy of the algebraic approximation adopted in ASM is examined using the numerical data given from LES. A new LES model with variable Smagorinsky constant is then presented.
The effect of airflow through an opening (or a crack) on the natural convection in a stairwell model is presented. The flow is driven by energy input from an electric panel heater located in the lower floor of the stairwell. The work concentrates on the effect of the size of inlet opening by varying it while keeping the area of the outlet constant. New data are presented for the measured temperatures and velocities at various cross-sections of the stairwell.
In modem livestock buildings air distribution and air quality are important parameters to animal welfare and to the health of full-time employees in animal production. Traditional methods for calculating air distribution in farm buildings are mainly based on formulas for air jets which do not include the effect of room geometry, obstacles or heat sources. This paper describes the use of Computational Fluid Dynamics to predict air flow patterns and temperature distribution in a ventilated space.
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