A theoretical investigation of supersonic jets in subsonic flow fields

Abstract

A method of calculating the development of a supersonic jet exhausting into a subsonic free stream is presented. The method of characteristics is used with the conditions on the jet boundary modified by the change in static pressure produced by the external stream. The method is particularly applied to cases where the inner boundary of the jet is a solid surface, e.g. the fan exhaust of a bypass engine. Theory and experiment are in close agreement for the range of jet pressure ratios and free-stream Mach numbers associated with engines of high bypass ratio.