modelling

Adsorption, desorption and chemisorption are known to impact the dispersal of volatile organic and chemically reactive compounds in buildings. These same three processes may be used to advantage to control the levels of these compounds indoors using building sorption filtration devices.

There is a need to calculate root mean square (r.m.s.) pressures from the output of steady-state computer programs. We know much less about calculating r.m.s. pressures than about calculating r.m.s. velocities. R.m.s. pressures can be quickly estimated from calculated mean pressures, mean velocities and r.m.s. velocities using the equations in this paper. The equations have been used in \Mind Engineering but can be applied in any turbulent flow where pressures are required.

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 paper considers issues pertaining to the capabilities and limitations of computational methods for multidimensional turbulent flows of the type encountered in fluids engineering. It argues that CFD, whilst offering considerable predictive power and potential, is not yet sufficiently well established to be applied routinely to complex 3D flows, unless only a rough qualitative. statement is being sought.

In order to evaluate the accuracy of COMIS predictions for large openings,and to study its sensitivity, two tests have been performed. In the first test, COMIS is used together with four existing multizone air flow models to calculate natural ventilation in a building for various climatic and opening configurations. In the second test, COMIS predictions are compared with single-sided ventilation measurements taken in test cells. The results of the tests are reported.

A sudden contamination of the outdoor air by some toxic gas can have several causes. To find out the protection afforded by sheltering indoors was the primary goal of the investigation. The object of the computational approach was a single family house with 2 floors. Three different models were utilized to calculate the infiltration air flows, the contaminant transport inside the building and the temperature decay of the building.