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

Stavropoulos, M.N., Mancinelli, M., Jordan, P., Jaunet, V., Weightman, J., Edgington-Mitchell, D.M., et al. (2023). The axisymmetric screech tones of round twin jets examined via linear stability theory. JOURNAL OF FLUID MECHANICS, 965 [10.1017/jfm.2023.398].

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

Mancinelli M.;Jordan P.;
2023-01-01

Abstract

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 the different waves supported by the flow at different conditions. Regions of the frequency-wavenumber domain for which the upstream-propagating guided jet modes are observed to be neutrally stable are observed to vary as a function of solution symmetry, jet separation, S, and the velocity profile used. Screech-frequency predictions performed using wavenumbers obtained from both models agree well with experimental data. Predictions obtained from the finite-thickness model better align with the screech tones measured experimentally and so are seen to be an improvement on predictions made with the vortex sheet. Additionally, results from the finite-thickness model predict both symmetric and antisymmetric screech tones for low S that are found in the vortex-sheet model only at greater S. The present results indicate that the feedback loop generating these screech tones is similar to that observed for single-jet resonance, with equivalent upstream and downstream modes.
2023
Stavropoulos, M.N., Mancinelli, M., Jordan, P., Jaunet, V., Weightman, J., Edgington-Mitchell, D.M., et al. (2023). The axisymmetric screech tones of round twin jets examined via linear stability theory. JOURNAL OF FLUID MECHANICS, 965 [10.1017/jfm.2023.398].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11590/470589
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