Suppression of Self-Sustained Oscillations in a Supersonic Impinging Jet

A passive control technique was used to suppress the self-sustained oscillations in a supersonic impinging jet. A rigid plate, placed in the ambient region close to the jet exit, was used to interrupt the upstream propagating acoustic waves originating from the impingement region. The effectiveness of this technique was examined using the particle image velocimetry. The results clearly showed that the large-scale coherent vortical structures, which dominated the normal impinging jet, are completely suppressed with the passive control technique. As a result, a signie cant reduction in induced entrainment velocity was found. A recovery of about 16% of the lift loss on the attached lift plate was achieved when compared to an uncontrolled impinging jet. A reduction of about 11 dB in the near-e eld overall sound pressure level was observed.