Abstract
Experimental studies of centerline velocity gradients for plain and flanged inlets in the 1930's and 1940's by Dalla Valle and Silverman are the bases for design equations in use today for local exhaust ventilation. Findings from these “classic” studies for circular, rectangular, and narrow slot inlets are presented and compared to experimental data obtained recently for high velocity/low volume exhaust nozzles. The application of Dalla Valle's equations for circular and rectangular inlets and Silverman's equations for narrow slots generally are confirmed. However, significant variations, particularly for flanged and rectangular configurations are noted. Implications resulting from experimental and analytical methodology are discussed.