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Near-wake characteristics of rigid and membrane wings in ground effect

Near-wake characteristics of rigid and membrane wings in ground effect
Near-wake characteristics of rigid and membrane wings in ground effect
Wind tunnel measurements are conducted at a Reynolds numbers of Re = 56,000 to examine the characteristics of near-wake vortices of rigid flat-plates and membrane wings from free-flight into ground–effect conditions. Synchronised high-speed load cell measurements, digital image correlation and particle image velocimetry are performed to resolve lift, drag and pitch oscillations simultaneously with membrane deformation and flow dynamics. Flow measurements are acquired in a crossflow-plane, one chord downstream of the trailing-edge, allowing the examination of time evolution of the wake and its relationship to the forces and membrane deformation. Membrane wings are found to delay ground–effect or high angles-of-attack induced tip-vortex break-down and result in larger tip-vortex push-out (beyond the wing span) compared to rigid flat-plate wings. The leading-edge vortex appears to shed with streamwise vorticity close to the root of the wing and this frequency of this shedding is found to match with the dominant frequency observed in membrane fluctuations. In specific resonance conditions, membrane and flow fluctuations are found to correlate well to the fluctuations in loads and moments.
0889-9746
199-216
Bleischwitz, Robert
461358e1-6d90-4a9d-bc11-4a68595d4b7a
De Kat, Roeland
d46a99a4-8653-4698-9ef4-46dd0c77ba5d
Ganapathisubramani, Bharathram
5e69099f-2f39-4fdd-8a85-3ac906827052
Bleischwitz, Robert
461358e1-6d90-4a9d-bc11-4a68595d4b7a
De Kat, Roeland
d46a99a4-8653-4698-9ef4-46dd0c77ba5d
Ganapathisubramani, Bharathram
5e69099f-2f39-4fdd-8a85-3ac906827052

Bleischwitz, Robert, De Kat, Roeland and Ganapathisubramani, Bharathram (2018) Near-wake characteristics of rigid and membrane wings in ground effect. Journal of Fluids and Structures, 80, 199-216. (doi:10.1016/j.jfluidstructs.2018.03.007).

Record type: Article

Abstract

Wind tunnel measurements are conducted at a Reynolds numbers of Re = 56,000 to examine the characteristics of near-wake vortices of rigid flat-plates and membrane wings from free-flight into ground–effect conditions. Synchronised high-speed load cell measurements, digital image correlation and particle image velocimetry are performed to resolve lift, drag and pitch oscillations simultaneously with membrane deformation and flow dynamics. Flow measurements are acquired in a crossflow-plane, one chord downstream of the trailing-edge, allowing the examination of time evolution of the wake and its relationship to the forces and membrane deformation. Membrane wings are found to delay ground–effect or high angles-of-attack induced tip-vortex break-down and result in larger tip-vortex push-out (beyond the wing span) compared to rigid flat-plate wings. The leading-edge vortex appears to shed with streamwise vorticity close to the root of the wing and this frequency of this shedding is found to match with the dominant frequency observed in membrane fluctuations. In specific resonance conditions, membrane and flow fluctuations are found to correlate well to the fluctuations in loads and moments.

Text
near wake Tipvortex_Paper_JFS_2018_Bleischwitz (1) - Accepted Manuscript
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More information

Accepted/In Press date: 14 March 2018
e-pub ahead of print date: 10 May 2018
Published date: July 2018

Identifiers

Local EPrints ID: 420746
URI: https://eprints.soton.ac.uk/id/eprint/420746
ISSN: 0889-9746
PURE UUID: 10937ed7-3944-4a50-8858-e8897fb3970d
ORCID for Roeland De Kat: ORCID iD orcid.org/0000-0002-6851-4409
ORCID for Bharathram Ganapathisubramani: ORCID iD orcid.org/0000-0001-9817-0486

Catalogue record

Date deposited: 14 May 2018 16:30
Last modified: 11 May 2019 04:01

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