EMBEDDED DETAILED ANALYSIS INTEGRATING CFD WITH MULTIZONE METHODS OF BUILDING AIRFLOW ANALYSIS

Methods of computational fluid dynamics (CFD) have been applied to predict the details of air,contaminant and thermal transport within isolated building zones, yet zone transport processes do notoccur in isolation they result from and interact with transport from the larger building system in whichthey are embedded. Consequently, there is a growing interest in combining CFD models of individualzones within multizone models of enclosing building systems to more faithfully model both the largerbuilding interactions and the intrazonal details. In the rush to combine these modeling capabilities,however, few have paused to consider the problem of embedded detailed analysis fundamentally.A fundamental approach based on mathematically coupling the CFD equations governing microscopicairflow in the embedded zone(s) to port plane formulations of the multi-zone equations governingmacroscopic airflow in the enclosing building system will be presented. Specifically, finite elementapproximations of both the Stokes Flow and the Reynolds Average Navier Stokes (RANS) equationswill be coupled to port plane formulations of the multizone equations and applied to a test case problemto illustrate the advantages of the approach and, yet, the limitations of embedded analysis in general.