Abstract
Motivated by the success of wavepackets in modelling the noise from subsonic and perfectly-expanded supersonic jets, we apply the wavepacket model to imperfectly expanded supersonic jets. Previous work by Savarese et al. [1] adopted a kinematic single-point wavepacket model first formulated by Lele [2]. Recent studies with subsonic jets, however, have demonstrated the importance of capturing the ‘jittering’ of wavepackets in order to correctly predict the intensity of far-field sound. Following the analysis of Cavalieri and Agarwal [3], we extend their methodology to model the acoustic sources of broadband shock-associated noise in imperfectlyexpanded supersonic jets using cross-spectral densities of the turbulent and shock-cell velocity quantities. We model the downstream propagating vortices as wavepackets, with the aim of determining the relationship between coherence decay, the statistical representation of jitter, and broadband shock-associated noise. Unlike the subsonic case where inclusion of coherence decay amplifies sound pressure level over the whole acoustic spectrum, we find that it does not play a critical role in increasing sound amplitude for shock-cell noise. When higher-order shock-cell modes are used to capture high frequency noise, however, the inclusion of a jittering wavepacket is necessary.
Original language | English |
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Title of host publication | 2018 AIAA/CEAS Aeroacoustics Conference |
Publisher | American Institute of Aeronautics and Astronautics |
ISBN (Print) | 9781624105609 |
DOIs | |
Publication status | Published - 1 Jan 2018 |
Event | AIAA/CEAS Aeroacoustics Conference 2018 - Atlanta, United States of America Duration: 25 Jun 2018 → 29 Jun 2018 Conference number: 24th https://arc.aiaa.org/doi/book/10.2514/MAA18 |
Conference
Conference | AIAA/CEAS Aeroacoustics Conference 2018 |
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Country/Territory | United States of America |
City | Atlanta |
Period | 25/06/18 → 29/06/18 |
Internet address |