Direct Numerical Simulation of a Turbulent Boundary Layer over Acoustic Liners

Research output: Chapter in Book/Conference proceedings/Edited volumeConference contributionScientific


The nacelle of aircraft engines is coated with acoustic liners to reduce engine noise. An undesirable effect of these liners is that they increase aerodynamic drag. We study this drag penalty by performing Direct Numerical Simulations of a turbulent boundary layer over an acoustic liner array at friction Reynolds number, Re τ ≈ 850–2500. We use this simulation to confirm several findings that we recently brought forward using a simpler channel flow setup. We show that acoustic liners lead to high wall-normal velocity fluctuations that can be directly correlated with a modulation of the classical near-wall cycle and to an increase in drag. We also confirm that the acoustic liners act as permeable surface roughness and the non-linear Forchheimer coefficient is the relevant permeability parameter for scaling the drag increase.
Original languageEnglish
Title of host publicationAIAA AVIATION 2023 Forum
PublisherAmerican Institute of Aeronautics and Astronautics Inc. (AIAA)
Number of pages8
ISBN (Electronic)978-1-62410-704-7
Publication statusPublished - 2023
EventAIAA AVIATION 2023 Forum - San Diego, United States
Duration: 12 Jun 202316 Jun 2023


ConferenceAIAA AVIATION 2023 Forum
Country/TerritoryUnited States
CitySan Diego

Bibliographical note

Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project
Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.


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