Turbulent recirculating flows in many types of ventilated rooms are numerically simulated three-dimensionally by means of k-e 2-equation turbulence model. The results obtained from numerical simulation are compared with those given by model experiments concerned with air velocity and contaminant diffusion.

Long term measurements of attic wood moisture content have shown that at least fifty kilograms of water may be stored in roof sheathing members over the course of the winter, to be released in the spring. Overlaid on this seasonal cycle there is a daily variation driven by temperature changes in the attic. A dynamic model is required to predict the resulting attic air humidity ratio. Hourly moisture flows in a typical attic - from ventilation and from the wood - are examined, and a simple first-principles dynamic mathematical model to relate them is developed.