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Broadband Predictions of Optimized Proprotors in Axial Forward FlightA low-fidelity toolchain was used to predict broadband self-noise trends for three proprotors in axial flight: a baseline (C24ND) and two acoustically constrained proprotors (OPT-III and COPR-3). Rotor loads were predicted with the ANOPP Propeller Analysis System (PAS) and self-noise was predicted with the semiempirical method of Brooks, Pope, and Marcolini (BPM) implemented in the ANOPP2 Self-Noise Internal Functional Module (ASNIFM). Comparisons to experimental data revealed that trends for turbulent boundary layer trailing edge (TBL-TE) noise could be modeled across several flight conditions by increasing the boundary layer thicknesses via the trip setting. Since the Mach number range of the BPM method is exceeded in these predictions, a dependence of boundary layer displacement thickness on blade station Mach number was suggested as a possible reason for needing to model thicker boundary layers, suggesting that the TBL-TE model needs to be developed further. Bluntness vortex shedding noise (BVS) predictions required tuning the trailing edge thickness and trailing edge closure angle for each flight condition to match experimental trends, demonstrating that the BVS noise model is incomplete and that BVS noise may vary with the angle of attack. This study indicates that the BPM self-noise method needs to be improved, which will lead to more accurate broadband predictions.
Document ID
20230006442
Acquisition Source
Langley Research Center
Document Type
Presentation
Authors
Joshua Blake
(Langley Research Center Hampton, Virginia, United States)
Chris Thurman
(Langley Research Center Hampton, Virginia, United States)
Nik Zawodny
(Langley Research Center Hampton, Virginia, United States)
Len Lopes
(Langley Research Center Hampton, Virginia, United States)
Date Acquired
April 26, 2023
Subject Category
Acoustics
Aerodynamics
Meeting Information
Meeting: AIAA AVIATION Forum and Exposition 2023
Location: San Diego, CA
Country: US
Start Date: June 12, 2023
End Date: June 16, 2023
Sponsors: American Institute of Aeronautics and Astronautics
Funding Number(s)
WBS: 109492.02.07.07.03
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
Technical Review
NASA Peer Committee
Keywords
Broadband self-noise
ASNIFM
ANOPP2
BPM
TBL-TE
BVS
bluntness noise
trailing edge noise
axial flight
proprotor
low-fidelity
optimization
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