 investig superson speed effect jet mach number diverg angl nozzl pressur base annulu bodi revolut investig superson speed effect jet mach number diverg angl nozzl pressur base annulu bodi revolut investig conduct langlei 9-inch superson tunnel determin jet effect vari jet mach number nozzl diverg angl pressur base annulu model cylindr afterbodi test conduct wide rang jet static pressur ratio reynold number free-stream mach number 1 62 1 94 2 41 test conduct artifici induc turbul boundari layer model lower rang jet static pressur ratio jet flow sonic superson nozzl pressur act base annulu essenti manner naca rm e53h25 cover jet static pressur ratio base pressur level increas jet static pressur ratio extrem static pressur ratio reach test sonic nozzl base pressur began decreas lower rang jet static pressur ratio nozzl diverg angl gener larger base pressur nozzl mach number increas base pressur chang diverg angl 0 10 small compar increas diverg angl chang data indic effect diverg angl reduc ratio jet exit diamet base diamet decreas jet mach number effect increas increas stream mach number 