Experiments in Fluids

, Volume 50, Issue 6, pp 1671–1684 | Cite as

Lift enhancement and flow structure of airfoil with joint trailing-edge flap and Gurney flap

Research Article

Abstract

The impact of Gurney flaps (GF), of different heights and perforations, on the aerodynamic and wake characteristics of a NACA 0015 airfoil equipped with a trailing-edge flap (TEF) was investigated experimentally at Re = 2.54 × 105. The addition of the Gurney flap to the TEF produced a further increase in the downward turning of the mean flow (increased aft camber), leading to a significant increase in the lift, drag, and pitching moment compared to that produced by independently deployed TEF or GF. The maximum lift increased with flap height, with the maximum lift-enhancement effectiveness exhibited at the smallest flap height. The near wake behind the joint TEF and GF became wider and had a larger velocity deficit and fluctuations compared to independent GF and TEF deployment. The Gurney flap perforation had only a minor impact on the wake and aerodynamics characteristics compared to TEF with a solid GF. The rapid rise in lift generation of the joint TEF and GF application, compared to conventional TEF deployment, could provide an improved off-design high-lift device during landing and takeoff.

List of symbols

b

Wing span

c

Airfoil chord

Cd

Section drag coefficient

Cl

Section lift coefficient

Cl,max

Maximum lift coefficient

Cl

Lift-curve slope

Cm

Section pitching moment coefficient about ¼-chord

Cm,peak

Peak pitching moment coefficient

Cp

Surface pressure coefficient

d

Perforation hole diameter

h

Gurney flap height

Re

Reynolds number, = Uc

u

Mean streamwise velocity

u

Streamwise velocity fluctuation

U

Freestream velocity

x, y, z

Streamwise, transverse and spanwise direction

α

Angle of attack

αss

Static-stall angle

αzl

Zero-lift angle

δ

Trailing-edge flap deflection

σ

Flap porosity

ζ

Mean streamwise vorticity

ν

Kinematic viscosity

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Copyright information

© Springer-Verlag 2010

Authors and Affiliations

  1. 1.Department of Mechanical EngineeringMcGill UniversityMontrealCanada

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