Numerical investigation supersonic jet near field with a longitudinal slit cutout on the expiration channel

摘要

The effects of a slit cutout length on the parameters of a supersonic flow are studied. The flow in the nozzle with a Mach number M = 2 was simulated numerically. The jet from the nozzle passed through the 30 cm long tube and then exhausted into quiescent air. Two symmetrical longitudinal slits were cut at the end of the tube. Three cases with 3, 6, and 9 cm cutouts were considered. The slit width was fixed at 1 cm for all cases. The study showed that an increase in the cutouts length leads to a slight increase in the mixing zone width at the jet boundary. However, the mixing intensity gradient was decreased. This flow case is somewhat similar to the chevrons used in some practical applications. So the cutouts can be used to reduce the intensity of the acoustic noise in the far field.