Jet exhaust noise reduction system and method

摘要

A system for reducing jet noise emission from an internally mixed gas turbine engine exhaust, comprising a fan/core flow mixer having a plurality of mixer lobes and a common flow nozzle having an equal number of tabs located along a circumferential edge of an aft end of the nozzle. There is a predetermined clocking relationship between the plurality of mixer lobes and the plurality of nozzle tabs that results in reduced exhaust noise emission, most evident in the lower frequency range. A method for reducing jet noise emission from an internally mixed gas turbine engine exhaust comprises selectively aligning a circumferential distribution of a mixed flow vorticity field produced by a fan/core mixer with a circumferentially distributed exhaust flow vorticity field produced by a modified common flow nozzle at an exit plane of the engine exhaust.