Jet Noise Scaling in Dual Stream Nozzles

摘要: Power spectral laws in dual stream jets are studied by considering such flows a superposition of appropriate single-stream coaxial jets. Noise generation each mixing region is modeled using power developed earlier for single as function jet temperature and observer angle. Similarity arguments indicate that noise nozzles may be considered composite four representing primary/secondary, secondary/ambient, transition, fully mixed zones. Frequency filter designed to highlight contribution from jet. Predictions provided at an area ratio 2.0--bypass 0.80 3.40, compared with measurements within wide range velocity ratios. These models suggest the low frequency unheated dominated all ratios, while high secondary when larger than 0.80. Transition equally dominate heated At ratios less 0.50, primary/bypass becomes significant contributing factor similar secondary/ambient