Elimination of screech tone noise in supersonic swirling jets

Generating a sufficient degree of swirl in underexpanded jets coming from a convergent nozzle is capable of eliminating the quasiperiodic shock cells that are essential components in the production of screech tone noise. Imparting swirl to a supersonic jet removes the presence of the fourth and fifth shock shells that cause the screech tone noise. The study also proved that flow recirculation alone is not capable of eliminating the quasiperiodic shock shell structure.