Work

Phononic compliant surfaces for the suppression of travelling-wave flutter instabilities in boundary-layer flows

Year: 2025

Type: article

Abstract: Compliant walls made from homogeneous viscoelastic materials may attenuate the amplification of Tollmien–Schlichting waves (TSWs) in a two-dimensional boundary-layer flow, but they also amplify travelling-wave flutter (TWF) instabilities at the interface between the fluid and the solid, which may lead to a premature laminar-to-turbulent transition. To mitigate the detrimental amplification of TWF, we propose to design compliant surfaces using phononic structures that aim at avoiding the propagation of elastic waves in the solid in the frequency range corresponding to the TWF. Thus, stiff inserts are periodically incorporated into the viscoelastic wall in order to create a band gap in the frequency spectrum of the purely solid modes. Fluid–structural resolvent analysis shows that a significant reduction in the amplification peak related to TWF is achieved while only marginal deterioration in the control of TSWs is observed. This observation suggests that the control of TSWs is still achieved by the overall compliance of the wall, while the periodic inserts inhibit the amplification of TWF. Bloch analysis is employed to discuss the propagation of elastic waves in the phononic surface to deduce design principles, accounting for the interaction with the flow.

Source: Journal of Fluid Mechanics

DOI: 10.1017/jfm.2025.10655

Authors: Nicolò Fabbiane, Olivier Marquet, Lorenzo Pierpaoli, Régis Cottereau, Marie Couliou

Institutions: Office National d'Études et de Recherches Aérospatiales, Institut Polytechnique de Paris, Laboratoire de Mécanique et d’Acoustique

Language: English

Topic: Fluid Dynamics and Turbulent Flows

Subfield: Computational Mechanics

Field: Engineering

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $3,550

Funders: Délégation Générale pour l'Armement, Office National d'études et de Recherches Aérospatiales