Investigation Of Net Thrust And Base Pressure Characteristics Of Cylindrical Afterbodies With Clustered Supersonic Nozzles At Transonic Mach Numbers PDF Download

A wind-tunnel investigation was conducted at Mach numbers from 0.9 to 1.4. Design Mach numbers of the nozzles were 2.0 and 2.5 and the number of clustered nozzles ranged from two to six. The nozzles had throat-to-base diameter ratios of 0.155, 0.225, 0.278, and 0.320. Some models were tested with various configurations of extended, shrouded, flush, and canted nozzles. The nozzles discharged unheated air from the base at ratios of jet total pressure to free-stream static pressure ranging from 1 to approximately 20. Results showed that both the ratio of total exit area to base area and the number of jets affect the netthrust factor to a significant degree for the extended-nozzle configurations. Good net-thrust factors were obtained with all the model configurations near the design jet total-pressure ratio; however, the extended-nozzle configuration had the highest net-thrust factor over the test jet total-pressure-ratio range. Canting the twin nozzles outward resulted in a favorable thrust factor over a limted jet total-pressureratio range. (Author).