Mathematical modelling approaches to air infiltration and ventilation applications.

The objective of this paper is to highlight the range of air infiltration and ventilation models that are available to the designer and to indicate the appropriate level of associated computer hardware that is necessary to support these modelling methods. The description begins with a discussion on simple empirical methods intended for basic design calculations. The applicability of these methods is discussed and some of their shortcomings are highlighted. Theoretically based flow modelling methods are then considered with particular emphasis on an appraisal of the numerical representation of the flow mechanisms and of the associated driving forces. The minimum data requirements which are necessary in order to undertake reliable design simulations are also outlined. The paper concludes with a description of some currently available algorithms, guidelines on selecting an appropriate technique for specific applications and an analysis of the reliability and uncertainties of present calculation methods.