Dynamic pitching effect on a laminar separation bubble
Dynamic pitching effect on a laminar separation bubble
The unsteady effect of a periodic pitching motion on the characteristic of a laminar separation bubble on the suction side of a SD7003 aerofoil is investigated by means of time-resolved planar and tomographic particle image velocimetry. The measurements provide information on the separation, transition and vortex roll-up onset as well as the spanwise distribution of vortical structures, for both the dynamic pitching between 4° and 8° and corresponding cases at a static pitch angle. During pitching, a clear hysteresis behaviour is observed for the vortex roll-up position and shedding frequency, showing a strongly delayed recovery of the shear layer with respect to the steady aerofoil case. The development of the shear layer transition exhibits initially 2D Kelvin–Helmholtz rollers that are interrupted, forming ?-shaped rollers, which eventually evolve into 3D arch-shaped hairpin structures. The 3D analysis of undulated rollers allowed the determination of the rollers streamwise spatial separation for both static and pitching aerofoil cases
1-17
Nati, A.
faf74188-ba44-4f87-83af-4bbda0f15bab
de Kat, R.
d46a99a4-8653-4698-9ef4-46dd0c77ba5d
Scarano, F.
64d9932b-d96e-4e8b-8849-45f320429912
van Oudheusden, B.W.
2e0bdc67-1e33-4654-964f-3820342f4afd
19 August 2015
Nati, A.
faf74188-ba44-4f87-83af-4bbda0f15bab
de Kat, R.
d46a99a4-8653-4698-9ef4-46dd0c77ba5d
Scarano, F.
64d9932b-d96e-4e8b-8849-45f320429912
van Oudheusden, B.W.
2e0bdc67-1e33-4654-964f-3820342f4afd
Nati, A., de Kat, R., Scarano, F. and van Oudheusden, B.W.
(2015)
Dynamic pitching effect on a laminar separation bubble.
Experiments in Fluids, 56 (172), .
(doi:10.1007/s00348-015-2031-6).
Abstract
The unsteady effect of a periodic pitching motion on the characteristic of a laminar separation bubble on the suction side of a SD7003 aerofoil is investigated by means of time-resolved planar and tomographic particle image velocimetry. The measurements provide information on the separation, transition and vortex roll-up onset as well as the spanwise distribution of vortical structures, for both the dynamic pitching between 4° and 8° and corresponding cases at a static pitch angle. During pitching, a clear hysteresis behaviour is observed for the vortex roll-up position and shedding frequency, showing a strongly delayed recovery of the shear layer with respect to the steady aerofoil case. The development of the shear layer transition exhibits initially 2D Kelvin–Helmholtz rollers that are interrupted, forming ?-shaped rollers, which eventually evolve into 3D arch-shaped hairpin structures. The 3D analysis of undulated rollers allowed the determination of the rollers streamwise spatial separation for both static and pitching aerofoil cases
Text
art%3A10.1007%2Fs00348-015-2031-6.pdf
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Accepted/In Press date: 6 July 2015
Published date: 19 August 2015
Organisations:
Aerodynamics & Flight Mechanics Group
Identifiers
Local EPrints ID: 380883
URI: http://eprints.soton.ac.uk/id/eprint/380883
ISSN: 0723-4864
PURE UUID: 259ef56b-d784-4624-87b6-99e99e7846ca
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Date deposited: 18 Sep 2015 10:39
Last modified: 14 Mar 2024 21:06
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Contributors
Author:
A. Nati
Author:
R. de Kat
Author:
F. Scarano
Author:
B.W. van Oudheusden
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