0
Research Papers: Flows in Complex Systems

On the Role of Leading-Edge Bumps in the Control of Stall Onset in Axial Fan Blades

[+] Author and Article Information
Alessandro Corsini

e-mail: alessandro.corsini@uniroma1.it

Giovanni Delibra

e-mail: giovanni.delibra@uniroma1.it
Department of Mechanical and Aerospace
Engineering,
Sapienza University of Rome,
Via Eudossiana 18,
Roma 00184, Italy

Anthony G. Sheard

Fläkt Woods Limited,
Axial Way,
Colchester Essex,
CO4 5ZD, UK
e-mail: geoff.sheard@flaktwoods.com

Contributed by the Fluids Engineering Division of ASME for publication in the JOURNAL OF FLUIDS ENGINEERING. Manuscript received September 3, 2012; final manuscript received March 27, 2013; published online June 5, 2013. Assoc. Editor: Chunill Hah.

J. Fluids Eng 135(8), 081104 (Jun 05, 2013) (9 pages) Paper No: FE-12-1424; doi: 10.1115/1.4024115 History: Received September 03, 2012; Revised March 27, 2013

Taking a lead from the humpback whale flukes, characterized by a series of bumps that result in a sinusoidal-like leading edge, this paper reports on a three-dimensional numerical study of sinusoidal leading edges on cambered airfoil profiles. The turbulent flow around the cambered airfoil with the sinusoidal leading edge was computed at different angles of attack with the open source solver OpenFOAM, using two different eddy viscosity models integrated to the wall. The reported research focused on the effects of the modified leading edge in terms of lift-to-drag performance and the influence of camber on such parameters. For these reasons a comparison with a symmetric airfoil is provided. The research was primarily concerned with the elucidation of the fluid flow mechanisms induced by the bumps and the impact of those mechanisms on airfoil performance, on both symmetric and cambered profiles. The bumps on the leading edge influenced the aerodynamic performance of the airfoil, and the lift curves were found to feature an early recovery in post-stall for the symmetric profile with an additional gain in lift for the cambered profile. The bumps drove the fluid dynamic on the suction side of the airfoil, which in turn resulted in the capability to control the separation at the trailing edge in coincidence with the peak of the sinusoid at the leading edge.

Copyright © 2013 by ASME
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Fig. 1

Left: humpback whale (from Wikipedia) and right: detail of the whale pectoral fin or flipper with its tubercles

Grahic Jump Location
Fig. 2

Planform of a humpback whale pectoral fin, after Fish et al. [16]

Grahic Jump Location
Fig. 3

Computational domain (top) and grid over the airfoil (bottom)

Grahic Jump Location
Fig. 4

Lift coefficient versus AoA for NACA0015. ♦: exp [26] (Re = 360,000); ▪: computations (Re = 183,000).

Grahic Jump Location
Fig. 5

Lift coefficient versus AoA. WHALE0015 and WHALE4415 identify the sinusoidal leading edge blades.

Grahic Jump Location
Fig. 6

Drag coefficient versus AoA. WHALE0015 and WHALE4415 identify the sinusoidal leading edge blades.

Grahic Jump Location
Fig. 7

WHALE4415 recirculation zone at AoA = 21 deg for Launder-Sharma model (left) and cubic model (right)

Grahic Jump Location
Fig. 8

Pressure coefficient distribution along the blade at different span positions for WHALE0015 (left) and WHALE4415 (right) profiles at AoA = 21 deg. NACAxx15 data are provided as well for comparison.

Grahic Jump Location
Fig. 9

Pressure coefficient distribution on the pressure side (left) and suction side (right) at different AoA for WHALE0015

Grahic Jump Location
Fig. 10

Pressure coefficient distribution on the pressure side (left) and suction side (right) at different AoA for WHALE4415

Grahic Jump Location
Fig. 11

WHALE4415 (AoA = 21 deg): An insight on the distortion of the velocity field generated by the leading edge (2D vectors constructed with span- and pitchwise velocity components)

Grahic Jump Location
Fig. 12

Velocity profiles at 90% of the chord in three different lines at 5%, 10%, and 15% of chord distance from the blade surface (see sketch)

Grahic Jump Location
Fig. 13

Vorticity profiles at 90% of the chord in three different lines at 5%, 10%, and 15% of chord distance from the blade surface (see sketch)

Grahic Jump Location
Fig. 14

A view of suction side with enstrophy isosurfaces: AoA = 10 deg (left) and 21 deg (right) for cambered (top) and symmetric (bottom) airfoil

Grahic Jump Location
Fig. 15

A view of pressure side with enstrophy isosurfaces: AoA = 10 deg (left) and 21 deg (right) for cambered (top) and symmetric (bottom) airfoil

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In