Modal Analysis of Buffet Effects Induced by Ultrahigh Bypass Ratio Nacelle Installation

Fuente: arXiv
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Autori principali: Spinner, Sebastian, Weiner, Andre
Natura: Preprint
Pubblicazione: 2026
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author Spinner, Sebastian
Weiner, Andre
author_facet Spinner, Sebastian
Weiner, Andre
contents Unsteady shock-boundary-layer interaction on the lower surface of a transport-aircraft wing can be caused or amplified by ultrahigh-bypass-ratio underwing nacelle installation. This work analyzes the resulting buffet dynamics on the Airbus XRF-1 configuration at a Mach number of $0.84$, a Reynolds number of $3.3\times 10^6$, and $-4^\circ$ angle of attack using scale-resolving delayed detached eddy simulations and unsteady pressure-sensitive paint measurements. Coherent structures are extracted employing a data-efficient multi-taper spectral POD. Dominant modes occur in the Strouhal number range $St \in [0.1,0.3]$. Surface modes reveal wave-like shock motions that originate near the pylon-wing intersection and propagate inboard towards the fuselage. These shock oscillations are linked to unsteady flow separation downstream of the shock. Additional dominant modes show spanwise oscillations of the separated flow region and shock oscillations phase-linked to shear layer instabilities. The modal analysis of volume data reveals pressure waves connected to these modes traveling upstream above and below the wing.
format Preprint
id arxiv_https___arxiv_org_abs_2602_16443
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Modal Analysis of Buffet Effects Induced by Ultrahigh Bypass Ratio Nacelle Installation
Spinner, Sebastian
Weiner, Andre
Fluid Dynamics
Unsteady shock-boundary-layer interaction on the lower surface of a transport-aircraft wing can be caused or amplified by ultrahigh-bypass-ratio underwing nacelle installation. This work analyzes the resulting buffet dynamics on the Airbus XRF-1 configuration at a Mach number of $0.84$, a Reynolds number of $3.3\times 10^6$, and $-4^\circ$ angle of attack using scale-resolving delayed detached eddy simulations and unsteady pressure-sensitive paint measurements. Coherent structures are extracted employing a data-efficient multi-taper spectral POD. Dominant modes occur in the Strouhal number range $St \in [0.1,0.3]$. Surface modes reveal wave-like shock motions that originate near the pylon-wing intersection and propagate inboard towards the fuselage. These shock oscillations are linked to unsteady flow separation downstream of the shock. Additional dominant modes show spanwise oscillations of the separated flow region and shock oscillations phase-linked to shear layer instabilities. The modal analysis of volume data reveals pressure waves connected to these modes traveling upstream above and below the wing.
title Modal Analysis of Buffet Effects Induced by Ultrahigh Bypass Ratio Nacelle Installation
topic Fluid Dynamics
url https://arxiv.org/abs/2602.16443