ESDU 98011: Aerofoil incidence for zero lift in subsonic two- dimensional flow.

Abstract:

ESDU 98011 gives a method for predicting the viscous zero-lift incidence of aerofoils. The method applies to aerofoils with simple or complex camber lines and accounts for the effect of compressibility, but is limited to subcritical flows. The boundary layer thicknesses at the trailing edge increase the zero-lift incidence above that predicted by inviscid theory. The method of Pankhurst is used to calculate the inviscid zero-lift incidence and two simple factors presented graphically are used to correct that value for the effects of viscosity and compressibility; both depend on the camber-line geometry in the vicinity of the trailing edge and Reynolds number while the latter also depends on Mach number. The VGK program was applied to a selection of aerofoils with a wide variety of camber-line shapes to derive the factors. The method applies to fully-attached flow and will therefore be unreliable for aerofoils with excessive thickness or camber. The accuracy of prediction of the viscous zero-lift incidence is within 0.2 degrees. Worked examples illustrate the use of the method.

A computer program of the method is included as part of ESDU LiCrA Toolbox apps and ESDUpacs A9931 and B9931 from (ESDU 99031). See the 'Software' tab, above.

Indexed under:

Details:

Data Item ESDU 98011
Format:	PDF with software
Status:	Original, issued 01 Sep 1998 Published in Release 2000-03 (init)
Previous Releases:	None available
ISBN:	978 1 86246 048 5

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This Data Item is complemented by the following software:

Toolbox Apps

Name

Details

Toolbox LiCrA-2D Run

Title

ESDU LiCrA: 2D Lift Curve Aerodynamics for Aerofoils

Version

1.0

Details

LiCrA 2D calculates the maximum lift coefficient, the lift coefficient at zero angle of attack and the lift curve of aerofoil sections with or without high-lift devices deployed at low speeds.

Calculations can be made for the aerofoil when there are no high-lift devices deployed but the prediction of the shape of the non-linear part of the lift curve should be treated with caution because it employs a technique developed for use when high-lift devices are deployed. The method is intended for use only for free-stream Mach numbers up to about 0.25.

Toolbox LiCrA-3D Run

Title

ESDU LiCrA: 3D Lift Curve Aerodynamics for Wings and Wing/Body Combinations

Version

1.0

Details

LiCrA 3D calculates the maximum lift coefficient, the lift coefficient at zero angle of attack and the lift curve of straight-tapered wings with or without high-lift devices deployed at low speeds. The basic wing (no devices deployed) may have camber and twist. The program includes methods that allow for the presence of a fuselage.

For completeness, calculations can be made for the wing when there are no high-lift devices deployed but the prediction of the shape of the non-linear part of the lift curve should be treated with caution because it employs a technique developed for use when high-lift devices are deployed. The method is intended for use only for free-stream Mach numbers up to about 0.25. No allowance is made for ground effect.

If required, it will also calculate the spanwise position of the section of the basic wing that has the peak loading due to angle of attack.