Tone injected nacelle for aeroacoustic wind tunnel testing

Abstract

An aeroacoustical test apparatus for evaluating a component. The apparatus includes a primary exhaust generating means which detects a primary gaseous flow through a primary passageway and out the primary nozzle. The apparatus further includes a secondary bypass flow generating means which directs bypass flow through a bypass passageway and out the secondary nozzle. An acoustical energy generating means having a sound transmitting axis is substantially centered on the longitudinal center axis of the apparatus. The acoustical energy generating means projects acoustical energy through a first centrally located acoustical coupler and a plurality of secondary acoustical couplers which extend around the primary exhaust generating means and into the secondary bypass passageway to cause the acoustical energy to exit from the secondary nozzle. Acoustical energy is generated by the acoustical energy generating means and acoustical energy flows into the first acoustical coupler and expands as it goes into the plurality of secondary acoustical couplers and expands further as it goes into the annular bypass passageway. The introduction of acoustical energy into the air in the annular bypass passageway results in the generation in that passageway of fan noise which would be created in the bypass duct of a jet engine employing the nozzle assembly being tested under actual operating conditions. A method for evaluating a component is also disclosed.