EXPERIMENTAL EVALUATION OF THE VELOCITY-FIELDS FOR LOCAL EXHAUST HOODS WITH CIRCULAR AND RECTANGULAR OPENINGS

A detailed experimental evaluation of the velocity fields induced in t he proximity of local exhaust hoods with circular and rectangular (rig ht quadrilateral) openings is presented. It contains a comprehensive d escription of the purpose-built test facility, of the measurement inst rumentation adopted, and of the experimental procedure in use. Results show that, for a given opening shape, the velocity fields are quite d ifferent for flanged or plain hood opening. Fluid-dynamic asymmetries, probably caused by possible instability phenomena (fluid stream attac hment) and by the influence of external supports or objects, are also observed. Further work on this topic is presented in a related paper [ F. Cascetta and L. Bellia, Building and Environment 31, 451-459 (1996) ]. Copyright (C) 1996 Elsevier Science Ltd.