Jet-Installation Noise Reduction with Permeable Flaps at In-Flight Conditions

Conference Paper (2022)
Author(s)

Leandro Rego (TU Delft - Wind Energy)

R. Zamponi (TU Delft - Wind Energy)

D. Ragni (TU Delft - Wind Energy)

Francesco Avallone (TU Delft - Wind Energy)

Damiano Casalino (TU Delft - Wind Energy)

M. Cruellas Bordes (German-Dutch Wind Tunnels (DNW))

Research Group
Wind Energy
Copyright
© 2022 Leandro Rego, R. Zamponi, D. Ragni, F. Avallone, D. Casalino, M. Cruellas Bordes
DOI related publication
https://doi.org/10.2514/6.2022-2874
More Info
expand_more
Publication Year
2022
Language
English
Copyright
© 2022 Leandro Rego, R. Zamponi, D. Ragni, F. Avallone, D. Casalino, M. Cruellas Bordes
Research Group
Wind Energy
ISBN (electronic)
978-1-62410-664-4
Reuse Rights

Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons.

Abstract

An experimental investigation on jet-installation noise reduction with permeable flaps on an aircraft half-model is performed, focusing on the effects on the noise levels as well as on the aerodynamic properties of the model (lift and drag forces). A nozzle with an exit diameter = 113 mm is included for generating a single-stream jet flow in the vicinity of the airframe. Two perforated flaps with different hole distributions are investigated. The first one has a uniform hole distribution with equal hole spacing in both streamwise and spanwise directions, whereas the second one has a gradient permeability with the hole spacing progressively decreasing towards the trailing edge. Aerodynamic force measurements, carried out with a balance, show that the permeable flaps are responsible for a lift reduction in the order of 7%, and a slight drag increase, in the order of 0.5%, with the gradient permeability flap outperforming the uniform one. Flow-field maps indicate that the effect on lift is linked to the formation of side-edge vortices at the spanwise positions corresponding to the discontinuity between solid and porous regions. Acoustic results obtained from phased array measurements show that the source at the flap trailing edge, generated by the interaction with the jet, reduces by 3 dB in amplitude with both permeable flaps, which perform similarly. Therefore, the permeable flaps are able to significantly reduce jet-installation noise for an aircraft configuration in flight conditions, however care must be taken in the design of the permeable structure in order to avoid aerodynamic degradation.

Files

6.2022_2874.pdf
(pdf | 2.74 Mb)
- Embargo expired in 02-01-2023
License info not available