Flow over a Wing with Leading-Edge Undulations

Alex Skillen (1) , Alistair Revell (1) , Alfredo Pinelli (2) , Ugo Piomelli (3) , Julien Favier (4)

1 MACE - School of Mechanical Aerospace and Civil Engineering [Manchester]
2 School of Engineering and Mathematical Sciences
3 Dept. of Mechanical and Materials Engineering
4 M2P2 - Laboratoire de Mécanique, Modélisation et Procédés Propres

The stall-delaying properties of the humpback whale flipper have been observed and quantified in recent years, through both experimental and numerical studies. In the present work we report numerical simulations of an infinite span wing with an idealised representation of this geometry, at a Reynolds number of 1.2 × 105 . Us- ing Large Eddy Simulation, we first establish an adequate spatial resolution before also examining the spanwise extent of the domain. We then proceed to analyse these results to provide an explanation of the conditions that drive the lift observed be- yond the conventional stall angle. The undulating leading-edge geometry gives rise to a span-wise pressure gradient that drives a secondary flow towards the regions of minimum chord. In turn, this leads to the entrainment of higher-momentum fluid into the region behind the maximum chord, which energises the boundary layer and delays stall. Aside from demonstrating a significant post-stall lift, the undulations also have the added benefit of substantially reducing lift fluctuations.

Mots clés: Flow control; leading edge bumps; whale; LES

Domaines: Mécanique des fluides [physics.class-ph]; Mécanique des fluides [physics.class-ph]

Alex Skillen, Alistair Revell, Alfredo Pinelli, Ugo Piomelli, Julien Favier. Flow over a Wing with Leading-Edge Undulations. AIAA Journal, 2014, 53 (2), pp.464-472. ⟨10.2514/1.J053142⟩. ⟨hal-01069899⟩