DOI: 10.1615/TSFP8
FLAPPING MOTION OF A SUPERSONIC RECTANGULAR JET, A REDUCED ORDER MODEL STUDY
ABSTRACT
This article describes an aeroacoustic feedback resonant mechanism observed in a rectangular supersonic jet operating at off design conditions. Strong acoustic waves, that have a narrow band non-linear behavior, are observed in the external flow field and the jet undergoes a strong coherent flapping motion.
A low order model study, based on POD analysis, is performed on dual-time schlieren visualization, allowing to relate the external acoustic waves and the coherent motion of the jet.
The main characteristics of this aero-acoustic feedback loop are investigated and it is shown that the behavior of the jet is not exactly similar to the well known screech phenomenon. Differences between the case studied here and a classical screech phenomenon are then discussed.