MODELING OF THE TURBULENT THERMAL-BOUNDARY-LAYER IMPLEMENTED IN CFD CODE N3S AND APPLICATION TO FLOWS IN HEATED AND COOLED ROOMS

This paper presents an efficient finite element method for solving the unsteady Navier-Stokes equations for turbulent incompressible flow co upled with thermal problems. This method has been implemented in the N 3S code, developed at Electricite de France. The lime discretization i s first described. We precise then the Chorin and the 'projected Uzawa ' algorithms used for the Stokes problem. Recent improvements concerni ng the optimization of finite element calculations are also detailed. The second part deals with the modelling of the thermal boundary layer used to simulate walls with fixed temperature in turbulent flows. The differences with other modelling suggested in the literature are disc ussed. The last part presents some applications. EDF is involved in th e conception of heating or cooling systems and numerical methods const itute a very useful tool to study the movements of air in habitations. The calculations are validated by comparisons with measurements.