Eduction of Vortical Structures in a Rectangular Jet by Fluctuating Pressure Measurements

Vortical structures in a rectangular jet were educed by measurements of phase-average fluctuating pressure, and the results were discussed in comparison with those by visualization experiments. The measurements were carried out for the air jet issuing from a sharp-edged rectangular orifice. The jet was excited at the interaction mode where the stable interaction of vortical structures was generated. In the phase-average measurements, reference signals were detected by an I-type hot-wire probe fixed near the jet center, and the phase-average fluctuating pressure was measured over the flow field with a pressure probe. The contours of phase-average fluctuating pressure provided us with more information on the details of vortical structures than visualization experiments. The results suggest that direct measurements of fluctuating pressure are very useful to detect the complicated vortical structures occurring in the rectangular jet.