Calculation of turbulent flow for building ventilation by means of jet profiles with regard to wall influences

Basis of this work was the question of the formation of air flows in ventilated test rooms with regard to wall influences. In order to determine the effects of the room geometry and the air inlet angle a on the airflow a jet which was placed just below the ceiling was observed in symmetrically designed test rooms. Since there is a correspondence between measurement and CFD simulation, velocity vectors are extrapolated from the CFD simulation and analysed for different geometrical data. It could be shown that due to the equilibrium of the wall shear stresses three-dimensional effects such as cross flows arise. Although two-dimensional inlet and outlet boundary conditions were defined they can produce symmetrical or non-symmetrical room air flows and a varying number of jet centerlines. An influence of the inlet angle a on the distance a and on the number of jet centerlines could be observed. The effect of room width B is small for an inlet angle up to a =30 and a room width greater than B=3H. The influence of the room length L is evident for L<3H. The comparison of the numerical calculation of the velocity profiles with the two dimensional wall jet model showed a considerable agreement in the plane of the jet centerline.