MACH WAVE ELIMINATION IN SUPERSONIC JETS

Experimental results are presented on a method that eliminates Mach wa ves from the exhaust of supersonic jets and, hence, that removes a str ong component of supersonic jet noise. Elimination is achieved by surr ounding the jet with an annular stream at prescribed velocity and temp erature so that all turbulent motions become intrinsically subsonic. N o mechanical suppressors are used. Implementation of the technique in a typical turbofan engine is estimated to increase takeoff thrust with minimal impact on overall fuel consumption.