The axisymmetric screech tones of round twin jets examined via linear stability theory

Spatial linear stability analysis is used to study the axisymmetric screech tones generated by twin converging round nozzles at low supersonic Mach numbers. Vortex-sheet and finite-thickness models allow for identification of different waves supported flow conditions. Regions frequency–wavenumber domain which upstream-propagating guided jet modes are observed be neutrally stable vary as a function solution symmetry, separation, $S$ , velocity profile used. Screech-frequency predictions performed using wavenumbers obtained from both agree well with experimental data. Predictions model better align measured experimentally so seen an improvement on made vortex sheet. Additionally, results predict symmetric antisymmetric that found in vortex-sheet only greater . The present indicate feedback loop generating these similar single-jet resonance, equivalent upstream downstream modes.