Coupling Modes of an Underexpanded Twin Axisymmetric Jet

Abstract

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Intermittent modal coupling in screeching underexpanded circular twin jets

“…It remains unclear whether the phase anomaly observed in both Knast et al. (2018) and Bell et al. (2018) is the signature of nonlinear interaction.…”

“…2009; Raman, Panickar & Chelliah 2012; Knast et al. 2018). The coupling behaviour has been observed to be a function of nozzle pressure ratio (NPR), nozzle spacing, boundary-layer thickness, shear-layer growth rate, nozzle geometry and the acoustic environment (Wlezien 1989; Morris 1990; Alkislar et al.…”

“…Knast et al. (2018) revisited the circular twin jet in a canonical set-up similar to Seiner et al. (1986), comparing experimental data to the frequency prediction relations developed by Powell (1953), Shen & Tam (2002) and Panda (1999).…”

Aeroacoustic resonance and self-excitation in screeching and impinging supersonic jets – A review

“…Clockwise from top left: axisymmetric-jet screech (flapping mode), elliptical-jet screech (flapping mode), 5 supersonic-jet impingement (helical mode), 6 twin-jet screech (coupled helical modes). 7 discrete-frequency sound; the desire to suppress this sound motivates much of the research into aeroacoustic resonance. An example of the intense tones is presented in Figure 2 for a screeching axisymmetric jet; both strong fundamental and harmonic tones are evident.…”

The generation of screech tones by shock leakage

“…2018; Knast et al. 2018). Interpretation of this relatively straightforward case will then facilitate a discussion of a more canonical single axisymmetric jet.…”