Effect of artificial streamwise vortexes on characteristics of supersonic jet

A parametric study of a microjet injection on the structure and acoustic radiation of a supersonic jet was carried out. The experiments were performed on a vertical jet facility of the ITAM SB RAS with an open working chamber. A supersonic underexpanded jet Ma=1, Npr=5, flowing out of the profiled nozzle Da=30 mm, was used. Ten different configurations were studied, in which the following gas-dynamic and geometric parameters of the experiment were changed one by one: pressure, injection distance, azimuthal, tangential, and axial tilt angles of the microjets. The flow was visualized using raster method and the noise characteristics of the supersonic jet were recorded at one of the points of the acoustic far field. It has been discovered that the microjet injection in general leads to an increase in the jet range and a decrease in the mixing intensity in the jet. The vicinity of the microjet injection point and the main nozzle exit section and the tangential angle of micronozzles inclination had the greatest effect on noise reduction.