ACOUSTIC LINERS' DISSIPATION ANALYSIS IN PRESENCE OF GRAZING FLOW USING HOWE’S ENERGY COROLLARY

Francesco Scarano; Angelo Paduano; Francesco Avallone

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Summary

Paper Title

ACOUSTIC LINERS' DISSIPATION ANALYSIS IN PRESENCE OF GRAZING FLOW USING HOWE’S ENERGY COROLLARY

Authors

Francesco Scarano
Angelo Paduano
Francesco Avallone

Modality

Onsite-Oral

Subject area

07.0. Aircraft Noise

Publishing Date

18/08/2025

Country of Publishing

Brazil | Brasil

Language of Publishing

Inglês

Paper Page

https://www.even3.com.br/anais/international-congress-exposition-noise-control-engineering/1070075-acoustic-liners-dissipation-analysis-in-presence-of-grazing-flow-using-howes-energy-corollary

ISBN

978-65-272-1573-8

Keywords

acoustic liners, noise absorption, acoustic dissipation by vortex shedding

Summary

Acoustic liners are installed in the intake of aircraft engines to absorb noise. In operating conditions, the acoustic liners are subjected to grazing acoustic waves and a turbulent boundary layer that develops over the nacelle. In presence of high sound pressure level (>140 dB) and grazing flow, the liner works in the so-called non-linear regime and the acoustic dissipation is governed by the vortex shedding formed at the mouths of the orifices. In addition, the grazing flow modifies the impedance of the liner. High fidelity simulations are conducted on a spatially evolving turbulent boundary layer interacting with a multi-orifice liner in presence of a grazing acoustic tone. The energy dissipated by vortex shedding and the topology of the dissipation are quantified using Howe’s energy corollary, a methodology applied here for the first time to acoustic liners. We demonstrate that, in absence of flow, the dissipation by shedding occurs in the inflow and outflow phases while the effect of the flow is to inhibit the vortex shedding in the outflow. This leads to an overall acoustic dissipation reduction by vortex shedding, with respect to the no-flow case, and a modification of the impedance.

Title of the Event: Inter-Noise 2025
City of the Event: São Paulo
Title of the Proceedings of the event: Proceedings of the 54th International Congress and Exposition on Noise Control Engineering
Name of the Publisher: Even3
Means of Dissemination: Meio Digital

How to cite

SCARANO, Francesco; PADUANO, Angelo; AVALLONE, Francesco. ACOUSTIC LINERS' DISSIPATION ANALYSIS IN PRESENCE OF GRAZING FLOW USING HOWE’S ENERGY COROLLARY.. In: Proceedings of the 54th International Congress and Exposition on Noise Control Engineering. Anais...Sao Paulo(SP) WTC Events Center, 2025. Available in: https//www.even3.com.br/anais/international-congress-exposition-noise-control-engineering/1070075-ACOUSTIC-LINERS-DISSIPATION-ANALYSIS-IN-PRESENCE-OF-GRAZING-FLOW-USING-HOWES-ENERGY-COROLLARY. Access in: 08/09/2025