In this chapter, the correlation between density and pressure fluctuation and
vortex motion is studied. The correlation between flow separation and vortex motion is
studied as well. The correlation clearly shows the vortex ring generation, size,
frequencies, and strength are closely related to the fluctuation of density and pressure.
This would provide a powerful tool for SBLI control and noise reduction.
Keywords: Correlation, Flow separation, Fluctuation, Mean value, Noise
reduction, Shock, Shock and vortex interaction, Vortex ring, Vorticity.