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.
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.
Direct capture efficiency of a local exhaust system is defined by introducing an imaginary control box surrounding the contaminant source and the exhaust opening. The imaginary box makes it possible to distinguish between contaminants directly captured and those that escape. Two methods for estimation of direct capture efficiency are given: (I) a numerical method based on the time-averaged Navier-Stokes equations for turbulent flows; and (2) a field method based on a representative background concentration.
Login