AbstractThe parallel solution of the incompressible Navier–Stokes equations coupled with the energy equation is considered. For turbulent flows, the k/ε model together with a modified wall‐function concept is used. The iterative process requires the fast solution of advection–diffusion reaction and Oseen‐type problems. These linearized problems are discretized using stabilized finite element methods. We apply a coarse–granular iterative substructuring method which couples the subdomain problems via Robin‐type interface conditions. Then we apply the approach to the simulation of indoor air flow problems. Copyright © 2002 John Wiley & Sons, Ltd.