modelling

This paper describes an innovative experimental technique that accurately reproduces natural ventilation flows, driven by the combined effects of stack and wind, at small scale in laboratory models of rooms or buildings. This technique provides a powerful tool for examining the performance of naturally ventilated buildings at the design stage as it may be used to predict quantitatively ventilation flow rates and temperature stratification under a wide range of climatic conditions.

This paper discusses two complementary techniques for modeling human exposures to airborne contaminants with a focus on control decisions involving ventilation. Particular attention is given to: (I) the use of empirical-conceptual models with dimensional analysis and (2) computational fluid dynamic simulations. Both techniques provide valuable information. An empirical -conceptual model is formulated with dimensional analysis for a spray painting operation.

The airflow in buildings involves a combination of many different flow elements. It is, therefore, difficult to find an adequate, all-round turbulence model covering all aspects. Consequently, it is appropriate and economical to choose turbulence models according to the situation that is to be predicted. This paper discusses the use of different turbulence models and their advantages in given situations. As an example, it is shown that a simple zero-equation model can be used for the prediction of special situations as flow with a low level of turbulence.

The subject of this paper is the experimental determination of the flow characteristics of three-dimensional wall jets. The jets were produced from a diffuser with a rectangular outlet. The diffuser outlet size and flow rate were varied to produce both low and high outlet aspect ratios and Reynolds numbers. Velocity profile measurements were made to determine the centerline velocity decay and the extent of the lateral and vertical spread of the jet.