Experimental Study of Influence of the Chevrons on Jet-Flap Interaction Noise

Abstract

The interaction noise of turbulent jet with deflected flap is considered. The test objects are small-scale models of turbulent jet and flap in scale 1:6. To compare the effect of chevrons on the interaction noise level, experiments are carried out for two types of conical nozzles: conventional and chevron. It is also used conventional flap and chevron flap. Noise measurements in acoustic far field are carried out in the PNRUP acoustic chamber for directions from 15 to 105 degrees with a step of 15 degrees. The flap deflection angle varied from 0 to 45 degrees in increments of 5 degrees. The results are compared with each other. It was found that the use of chevrons for nozzle and for flap has the effect of some reduction in the interaction noise. Moreover, the jet outflowing from the chevron nozzle, when interacting with chevron flap, gives lower noise level than when interacting with conventional flap.