The techniques available for the simulation of the complex geometries common in air diffusers are quite different from the ones optimized for a complete room simulation. For this reason the full room simulation usually neglects the complexities of the diffusers introducing ad hoc boundary con- ditions often requiring extensive experimental setups for a correct definition. An alternative approach could be the use of numerical analysis for the diffuser characterization. In this work a detailed analysis of a perforated plate type diffuser is performed, particular effort has been devoted to the perforated plate modeling comparing different possible approaches. The simulation has been carried out using the commercial code FLUENT 6.1
