The evolution of instabilities in the axisymmetric jet. Part 2. The flow resulting from the interaction between two waves

Abstract

Leading nonlinear interactions generated by waves externally superimposed on an axisymmetric jet are considered theoretically, and the results verified experimentally. The mean flow in the jet loses its axial symmetry whenever the jet is excited simultaneously by two different azimuthal modes of the same frequency. Subharmonic resonance occurs in this flow whenever the conditions warrant such an occurrence, generating azimuthal modes which may not have been present otherwise in this flow. Some of these resonance conditions are explored.