Aeroacoustic investigation of shrouded propeller systems
Aeroacoustic investigation of shrouded propeller systems
This paper presents an experimental, numerical, and analytical investigation into the influence of shroud length on the acoustic performance of ducted propeller systems, with relevance to Urban Air Mobility (UAM) and Unmanned Aerial Vehicle (UAV) applications. Building on previous work that examined intake geometry and acoustic liners, this study isolates the effect of the shroud length by comparing two configurations of different lengths under identical intake and thrust conditions. Far-field and in-duct noise measurements are presented and complemented by hot-wire flow diagnostics and numerical simulations using the Lattice-Boltzmann (LB) method. Additionally, a simplified analytical model is presented to assess the role of acoustic near-field effects in noise radiation. The results show that the longer duct configuration increases broadband noise at lower frequencies, while the shorter duct exhibits higher tonal and broadband noise at higher frequencies, particularly in the rear arc. Analytical predictions confirm that radiation effects due to source proximity to the intake are only significant when the source lies within half a wavelength of the duct inlet. For the configurations tested, these effects contribute less than 1 dB to the overall noise difference, indicating that source-related flow effects are dominant. The LB simulations show good agreement with experimental data and provide a foundation for future analysis of the noise generation mechanisms.
Acoustic Liner, Blade Passing Frequency, Flow Conditions, Law of the Wall, Numerical Simulation, Overall Sound Pressure Level, Propeller Noise, Shrouded Propellers, Unmanned Aerial Vehicle, Urban Air Mobility
American Institute of Aeronautics and Astronautics
Palleja Cabre, Sergi
b841a96c-05d1-4f08-a197-8693cb3a3f90
Ballgjati, Jona
64f225e3-84ae-42b6-9d7b-76dfaeb1bec0
Saraceno, Ivan
37e98610-bd4e-4cb6-96fa-f85b970a2a4e
Joseph, Phillip
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Paruchuri, Chaitanya
5c1def64-6347-4be3-ac2d-b9f6a314b81d
Avallone, Francesco
9bb6adef-cc50-498a-abca-497bca096a57
16 July 2025
Palleja Cabre, Sergi
b841a96c-05d1-4f08-a197-8693cb3a3f90
Ballgjati, Jona
64f225e3-84ae-42b6-9d7b-76dfaeb1bec0
Saraceno, Ivan
37e98610-bd4e-4cb6-96fa-f85b970a2a4e
Joseph, Phillip
9c30491e-8464-4c9a-8723-2abc62bdf75d
Paruchuri, Chaitanya
5c1def64-6347-4be3-ac2d-b9f6a314b81d
Avallone, Francesco
9bb6adef-cc50-498a-abca-497bca096a57
Palleja Cabre, Sergi, Ballgjati, Jona, Saraceno, Ivan, Joseph, Phillip, Paruchuri, Chaitanya and Avallone, Francesco
(2025)
Aeroacoustic investigation of shrouded propeller systems.
In,
AIAA Aviation Forum and Ascend 2025.
AIAA AVIATION FORUM AND ASCEND 2025 (21/07/25 - 25/07/25)
American Institute of Aeronautics and Astronautics.
(doi:10.2514/6.2025-3750).
Record type:
Book Section
Abstract
This paper presents an experimental, numerical, and analytical investigation into the influence of shroud length on the acoustic performance of ducted propeller systems, with relevance to Urban Air Mobility (UAM) and Unmanned Aerial Vehicle (UAV) applications. Building on previous work that examined intake geometry and acoustic liners, this study isolates the effect of the shroud length by comparing two configurations of different lengths under identical intake and thrust conditions. Far-field and in-duct noise measurements are presented and complemented by hot-wire flow diagnostics and numerical simulations using the Lattice-Boltzmann (LB) method. Additionally, a simplified analytical model is presented to assess the role of acoustic near-field effects in noise radiation. The results show that the longer duct configuration increases broadband noise at lower frequencies, while the shorter duct exhibits higher tonal and broadband noise at higher frequencies, particularly in the rear arc. Analytical predictions confirm that radiation effects due to source proximity to the intake are only significant when the source lies within half a wavelength of the duct inlet. For the configurations tested, these effects contribute less than 1 dB to the overall noise difference, indicating that source-related flow effects are dominant. The LB simulations show good agreement with experimental data and provide a foundation for future analysis of the noise generation mechanisms.
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More information
Published date: 16 July 2025
Venue - Dates:
AIAA AVIATION FORUM AND ASCEND 2025, , Las Vegas, United States, 2025-07-21 - 2025-07-25
Keywords:
Acoustic Liner, Blade Passing Frequency, Flow Conditions, Law of the Wall, Numerical Simulation, Overall Sound Pressure Level, Propeller Noise, Shrouded Propellers, Unmanned Aerial Vehicle, Urban Air Mobility
Identifiers
Local EPrints ID: 504966
URI: http://eprints.soton.ac.uk/id/eprint/504966
PURE UUID: 14f4ebd4-deef-4f72-be49-4c8456b1139f
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Date deposited: 23 Sep 2025 16:45
Last modified: 17 Oct 2025 02:22
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Contributors
Author:
Jona Ballgjati
Author:
Ivan Saraceno
Author:
Francesco Avallone
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