Definition of the flow parameters at the room inlet device - measurements and calculations.

Due to the limitations of computer storage and time the flow boundary conditions at an air inlet device have to be specified for numerical simulations of air flow patterns in rooms. With regard to this the present work gives velocity measurements near an industrial air inlet using a Laser-Doppler-Anemometer. From the stochastic velocity data the time-averaged velocity components, standard deviation and turbulent kinetic energy are evaluated. Furthermore the dissipation rate of the turbulent kinetic energy is determined from the time scale of the autoconelation coefficient and alternativly from the frequency spectrum of turbulence. The assumptions required for the calculations are discussed. Finally, measured data at a distance of one meter from the air inlet are compared with the numerically predicted velocity field and turbulence parameters, which are based on boundary conditions of a simplified inlet. Comparisons of numerically predicted air flow in the occupied zone show a significant difference depending on whether measured boundary conditions or those for a simplified slit are used. In particular the predicted turbulent kinetic energy for the simplified slit boundary condition is twice that for the measured boundary condition.