Noise Reduction in Subsonic Jets Using Chevron Nozzles

The exhaust of the jet engines used in commercial (subsonic) aircrafts produce a lot of noise known as jet noise. This noise has adverse effects on the population living nearby the airports. However, the noise levels are above the permissible limit and thus need more attention. This paper reviews some of the techniques for noise reduction and mainly focuses on the use of chevron nozzle in reducing the jet noise. Large eddy simulations are performed for a simple nozzle and chevron nozzle with triangular wedges at the rear circumference of the nozzle with same boundary conditions. Acoustic data is collected at different receiver locations to understand the effect of chevrons in jet noise reduction. The result of the simulations shows that chevrons are good attenuators of jet noise.