Incipient buffet over laminar-flow airfoil - a DNS study at moderate Reynolds numbers
Incipient buffet over laminar-flow airfoil - a DNS study at moderate Reynolds numbers
In order to study transonic buffet over aircraft wings, the linear stability of the flowfield is analysed based on direct numerical simulations at moderate Reynolds numbers. A significant change of the boundary layer stability depending on the aerodynamic load of the airfoil is suggested by local linear stability theory. Besides Kelvin Helmholtz instabilities, a global mode, showing the coupled dynamics of the separation bubbles, can be identified in agreement with literature. Both modes are present in a dynamic mode decomposition (DMD) of the unsteady direct numerical solution. Furthermore, DMD picks up the buffet-mode at a Strouhal number of St = 0.12 that agrees with experiments. Two additional modes with similar structure are observed at St = 0.45 and St = 0.6, suggesting that the observed buffet might involve triadic mode interactions , rather than being a single global mode.
Direct numerical simulation, Wing, Global stability analysis, Dynamic mode decomposition, Transonic buffet
87-92
Zauner, Markus
c0207f79-62cc-4909-8aa0-6bb9d99e1ea3
Sandham, Neil
0024d8cd-c788-4811-a470-57934fbdcf97
27 September 2018
Zauner, Markus
c0207f79-62cc-4909-8aa0-6bb9d99e1ea3
Sandham, Neil
0024d8cd-c788-4811-a470-57934fbdcf97
Zauner, Markus and Sandham, Neil
(2018)
Incipient buffet over laminar-flow airfoil - a DNS study at moderate Reynolds numbers.
In Proceedings ot the 12th International ERCOFTAC Symposium on Engineering Turbulence Modelling and Measurements.
.
Record type:
Conference or Workshop Item
(Paper)
Abstract
In order to study transonic buffet over aircraft wings, the linear stability of the flowfield is analysed based on direct numerical simulations at moderate Reynolds numbers. A significant change of the boundary layer stability depending on the aerodynamic load of the airfoil is suggested by local linear stability theory. Besides Kelvin Helmholtz instabilities, a global mode, showing the coupled dynamics of the separation bubbles, can be identified in agreement with literature. Both modes are present in a dynamic mode decomposition (DMD) of the unsteady direct numerical solution. Furthermore, DMD picks up the buffet-mode at a Strouhal number of St = 0.12 that agrees with experiments. Two additional modes with similar structure are observed at St = 0.45 and St = 0.6, suggesting that the observed buffet might involve triadic mode interactions , rather than being a single global mode.
Text
ETMM12 - Conference Proceedings
- Author's Original
More information
Published date: 27 September 2018
Venue - Dates:
The 12th International ERCOFTAC Symposium on Engineering Turbulence Modelling and Measurements, La Grande-Motte, Montpellier, France, 2017-09-26 - 2018-09-28
Keywords:
Direct numerical simulation, Wing, Global stability analysis, Dynamic mode decomposition, Transonic buffet
Identifiers
Local EPrints ID: 425396
URI: http://eprints.soton.ac.uk/id/eprint/425396
PURE UUID: 66e49ada-2e0c-48ce-b312-7e3446380b15
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Date deposited: 17 Oct 2018 16:30
Last modified: 17 Jul 2024 01:36
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Contributors
Author:
Markus Zauner
Author:
Neil Sandham
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