Non-homogeneous thermal boundary conditions may play a relevant role in flow fields within ventilated enclosures. One such large-scale (23 m(3)) test enclosure has been set in operation by termination jets under a combination of thermal unbalances in order to describe the dependence of secondary flow patterns on the bulk airflow. An integrated approach has therefore been attempted that features both measurements and calculations. An extensive and painstaking set of flow field measurements has been performed first, relative to different thermal and fluid dynamic working conditions, by means of a custom Laser Doppler Velocimetry apparatus. A commercial CFD software was then employed to perform the related calculations. A transitional regime is present ( Re approximate to 2000, based on grille diffuser equivalent diameter) at the given forcing inlet flow, as well as the competition between natural and forced convection. Some qualitative comparisons with respective experimental data are presented to delineate the role of thermal disturbances.