Leading-edge vortex dynamics on plunging airfoils and wings. (10th June 2022)

• Record Type: Journal Article
• Authors: Son, O.; Gao, A.-K.; Gursul, I.; Cantwell, C.D.; Wang, Z.; Sherwin, S.J.
• Is Part Of: Journal of fluid mechanics. Volume 940(2022)
• Publication Date: 2022-06-10
• Subjects: vortex dynamics; Fluid mechanics -- Periodicals; 532.005
• DOI: 10.1017/jfm.2022.224
• Languages: English
• ISSNs: 0022-1120

Abstract

Abstract: Abstract : The vortex dynamics of leading-edge vortices on plunging high-aspect-ratio ( AR = 10) wings and airfoils were investigated by means of volumetric velocity measurements, numerical simulations and stability analysis to understand the deformation of the leading-edge vortex filament and spanwise instabilities. The vortex filaments on both the wing and airfoil exhibit spanwise waves, but with different origins. The presence of a wing-tip causes the leg of the vortex to remain attached to the wing upper surface, while the initial deformation of the filament near the wing tip resembles a helical vortex. The essential features can be modelled as the deformation of an initially L -shaped semi-infinite vortex column. In contrast, the instability of the vortices is well captured by the instability of counter-rotating vortex pairs, which are formed either by the trailing-edge vortices or the secondary vortices rolled-up from the wing surface. The wavelengths observed in the experiments and simulations are in agreement with the stability analysis of counter-rotating vortex pairs of unequal strength.