Pulsed radial jet reattachment nozzle

Steady periodic surface pressure distributions have been obtained for a mec hanically pulsed radial jet reattachment (PRJR) nozzle. Local time-averaged and average Nusselt numbers have been obtained for air flow exiting a PRJR nozzle and impinging on a flat plate. The Nusselt numbers were obtained as ii function of the following nondimensional nozzle parameters: Reynolds nu mber, nozzle to plate spacing, exit angle, Strouhal number (pulsation frequ ency), exit gap spacing, and pulsation amplitude. The nozzle exit gap is cy clically varied for a PRJR nozzle, causing pulsations in the flow field tha t alter the convective coefficients and surface pressure distribution when compared to flow exiting an RJR nozzle under similar conditions. It was sho wn that the Nusselt number is a strong function of the Reynolds number, exi t angle, and the combined effects of nozzle height, pulsation amplitude, an d pulsation frequency. (C) 1999 Elsevier Science Ltd. All rights reserved.