Flow Characteristics of Dual Throat Thrust Vectoring Nozzles

The investigation was conducted to investigate the flow characteristics on the dual throat thrust vectoring nozzle. Based on a simplified aircraft afterbody model, the numerical calculation and the wind tunnel test were carried out to study the effect of the integrated design of aircraft afterbody on the flow characteristics. The impact of the main flow/vectoring jet flow interaction on the aircraft afterbody was further investigated. The results indicate that, the difference between the upside and downside wall pressures is the main reason for the generation of thrust vectoring, and this difference is created by the separated turbulent flows in the cavity. The wall pressure difference increases with the enhancement of the secondary injection flow rate. Then the thrust vector angle of nozzle increases. The thrust vector angle reach the peak value 16.6° without outflow at the conditions that the primary NPR=4.0 and the secondary NPR_s=4.8. While the peak thrust vector angle is 11.2° with outflow Ma=0.4. The dominant frequency of noise created from the nozzle cowl is within 900 Hz. The peak noise is located at the cowl configuration which changes sharply. The variation of the vectoring jet angle has no effect on the peak noise frequency, but only affects the amplitude below 1 000 Hz on the downside of nozzle cowl, and the influence of the maximum frequency spectrum amplitude is 2 dB.