Unsteady behaviour in direct numerical solutions of transonic flow around an airfoil
Unsteady behaviour in direct numerical solutions of transonic flow around an airfoil
In order to improve the aerodynamic performance and extend the flight envelope of next-generation aircraft, it is necessary to understand complex transonic flow phenomena on the wings and their impact on laminar-turbulent transition and flow separation. In particular, self-sustained low-frequency oscillations of shock waves, known as transonic buffet, are of great interest as they affect the aircraft handling and the structural integrity lifetime of the wings. This contribution addresses the flow characteristics at conditions where the onset of buffet phenomena is expected. We performed and analysed direct numerical simulations (DNS) of a supercritical laminar-wing section at moderate Reynolds numbers up to Re = 800,000 and an angle of attack of 4 degrees. It is shown that raising the Reynolds number increases the aerodynamic load on the wing significantly due to the reduced flow separation at the trailing edge. Simulations show upstream travelling pressure waves originating near the trailing edge and low-frequency oscillations in the lift coefficient. A distinct periodic forwards and backwards
motion of a permanent shock wave is not observed, but the frequency spectra of surface-density fluctuations at various positions show low-frequency phenomena similar to those observed in wind-tunnel tests at higher Reynolds numbers.
American Institute of Aeronautics and Astronautics
Zauner, Markus
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De Tullio, Nicola
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Sandham, Neil
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25 June 2018
Zauner, Markus
c0207f79-62cc-4909-8aa0-6bb9d99e1ea3
De Tullio, Nicola
db4397b2-3fab-476c-a0f4-4caf9848d5f7
Sandham, Neil
0024d8cd-c788-4811-a470-57934fbdcf97
Zauner, Markus, De Tullio, Nicola and Sandham, Neil
(2018)
Unsteady behaviour in direct numerical solutions of transonic flow around an airfoil.
In 2018 Fluid Dynamics Conference.
American Institute of Aeronautics and Astronautics.
14 pp
.
(doi:10.2514/6.2018-2911).
Record type:
Conference or Workshop Item
(Paper)
Abstract
In order to improve the aerodynamic performance and extend the flight envelope of next-generation aircraft, it is necessary to understand complex transonic flow phenomena on the wings and their impact on laminar-turbulent transition and flow separation. In particular, self-sustained low-frequency oscillations of shock waves, known as transonic buffet, are of great interest as they affect the aircraft handling and the structural integrity lifetime of the wings. This contribution addresses the flow characteristics at conditions where the onset of buffet phenomena is expected. We performed and analysed direct numerical simulations (DNS) of a supercritical laminar-wing section at moderate Reynolds numbers up to Re = 800,000 and an angle of attack of 4 degrees. It is shown that raising the Reynolds number increases the aerodynamic load on the wing significantly due to the reduced flow separation at the trailing edge. Simulations show upstream travelling pressure waves originating near the trailing edge and low-frequency oscillations in the lift coefficient. A distinct periodic forwards and backwards
motion of a permanent shock wave is not observed, but the frequency spectra of surface-density fluctuations at various positions show low-frequency phenomena similar to those observed in wind-tunnel tests at higher Reynolds numbers.
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6.2018-2911
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e-pub ahead of print date: 24 June 2018
Published date: 25 June 2018
Venue - Dates:
AIAA Aviation Forum: 2018 Fluid Dynamics Conference, , Atlanta, Georgia, 2018-06-25 - 2018-06-29
Identifiers
Local EPrints ID: 422148
URI: http://eprints.soton.ac.uk/id/eprint/422148
PURE UUID: 49d8314c-3d6d-4305-940b-909446d5d220
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Date deposited: 18 Jul 2018 16:30
Last modified: 13 Dec 2024 02:36
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Author:
Markus Zauner
Author:
Nicola De Tullio
Author:
Neil Sandham
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