Turbulent eddies in a compressible jet in crossflow measured using pulse-burst particle image velocimetry

摘要: Pulse-burst Particle Image Velocimetry (PIV) has been employed to acquire time-resolved data at 25 kHz of a supersonic jet exhausting into subsonic compressible crossflow. Data were acquired along the windward boundary shear layer and used identify turbulent eddies as they convect downstream in far-field interaction. Eddies found have tendency occur closely spaced counter-rotating pairs are routinely observed PIV movies, but variable orientation these makes them difficult detect statistically. Correlated vortices more strongly pass by larger spacing, both leading trailing reference eddy. This indicates paired nature for recur repeatable spacing. Velocity spectra reveal peak frequency consistent with this spacing between shear-layer rotating identical sign. The spatial scale appears si...