Experimental and Analytical Investigation of the Distortion of Turbulence Interacting with a Porous Airfoil

R. Zamponi, C Schram, S. Moreau, D. Ragni

Research output: Chapter in Book/Conference proceedings/Edited volumeConference contributionScientificpeer-review

3 Downloads (Pure)

Abstract

View Video Presentation: https://doi-org.tudelft.idm.oclc.org/10.2514/6.2021-2289.vid

A possible strategy for the reduction of the aeroacoustic noise generated by turbulence interacting with a wing profile, also referred to as leading-edge noise, is represented by the implementation of a porous medium in the structure of the airfoil. However, the physical mechanisms involved in this noise mitigation technique remain unclear. The present work aims at elucidating these phenomena and particularly how the porosity affects the incoming turbulence characteristics in the immediate vicinity of the surface. A porous NACA-0024 profile integrated with melamine foam has been compared with a solid baseline, both airfoils being in turn subjected to the turbulence shed by an upstream cylindrical rod. The mean wall-pressure distribution along the airfoils shows that the implementation of the porous material mostly preserves the integrity of the NACA-0024 profile’s shape. Results of hot-wire anemometry indicate that the porous design proposed in this study allows for damping of the velocity fluctuations and has a limited influence on the upstream mean flow field. Specifically, the upwash component of the root-mean-square of the velocity fluctuations turns out to be significantly attenuated in the porous case in contrast to the solid one. Furthermore, the comparison between the power spectral densities of the incident turbulent velocities demonstrates that the porosity has an effect mainly on the low-frequency range of the turbulent velocity power spectrum. This evidence is in line with the results of the acoustic beamforming measurements, which exhibit a noise abatement in an analogous frequency range. On the basis of these observations, an interpretation of the phenomena occurring in the turbulence-interaction noise reduction due to a porous treatment of the airfoil is finally given with reference to the theoretical inputs of the rapid distortion theory.
Original languageEnglish
Title of host publicationAIAA AVIATION 2021 FORUM
Number of pages20
ISBN (Electronic) 978-1-62410-610-1
DOIs
Publication statusPublished - 2021
EventAIAA Aviation 2021 Forum - Virtual Event
Duration: 2 Aug 20216 Aug 2021

Conference

ConferenceAIAA Aviation 2021 Forum
Period2/08/216/08/21

Fingerprint

Dive into the research topics of 'Experimental and Analytical Investigation of the Distortion of Turbulence Interacting with a Porous Airfoil'. Together they form a unique fingerprint.

Cite this