Features of experimental research of supersonic jet noise reduction

This work experimentally investigates an acoustic field of a supersonic block jet and suppression of the sound level by water injection. The research facility consists of a solid engine with five nozzles fixed in a horizontal position, and the circular manifold which can inject water jets into the mixing layer. It is stated that afterburning of solid fuel in a supersonic jet has significant influence on the intensity of the acoustic radiation, generating an additional discrete noise source. The experiments showed that the injection of water at an angle of 60° to the axis of the jet eliminates the discrete tone.