Effect of facility variations on the acoustic characteristics of three single stream nozzles

The characteristics of the jet noise produced by three single stream referee nozzles have been investigated statically at the NASA‐Lewis Research Center outdoor jet acoustic facility. These nozzles were a 712‐cm‐diam conical convergent, a 10‐cm‐diem conical convergent, and an 8‐lobe daisy nozzle with 712cm equivalent diameter flow area. The same nozzles have been previously tested in other facilities such as the Royal Aircraft Establishment 24‐ft acoustic wind tunnel. The test conducted covered pressure ratios from 1.4 to 2.5 at total temperatures of 810°K and ambient. Data were obtained using four different acoustic arena arrangements. Data taken with the different arrangements are compared. The results obtained are also compared with data from other facilities and with a prediction procedure developed elsewhere [i.e., Stone and Montegani (1979).]