Julien Berland, Christophe Bogey and Christophe Bailly Laboratoire de Mécanique des Fluides et d'Acoustique, UMR CNRS 5509, École Centrale de Lyon

Snapshot of the density modulus (gray), of the spanwise vorticity (purple and green) and of the near-field pressure (red), in a plane perpendicular to the spanwise direction. The hatched white surface represents the nozzle lips. The jet operates at fully expanded Mach number equal to 1.55, with Reynolds number 60,000 based on the jet height.

Compression shocks corresponding to high-density gradients are observed inside the jet plume. Upstream-propagating wave-fronts associated with screech tones radiation are also clearly visible on either side of the jet. In addition the simulation results have provided evidences of the connection between the shock-leakage process (Suzuki & Lele, J. Fluid Mech., 2003) and the generation of screech tones.

The photograph was taken by Berland J., Bogey C. and Bailly C in 2007, Numerical study of screech generation in a planar supersonic jet