Abstract:

ESDU Aero W.05.01.01 gives graphs of two parameters: wake thickness (measured normal to the freestream) divided by root chord and the kinetic pressure in the median plane of the wake divided by freestream kinetic pressure. Both parameters are plotted against wing profile drag coefficient and distance aft of the trailing edge of the wing root non-dimensionalised with root chord. The variation of the kinetic pressure through the wake thickness is plotted in a third graph. The data apply to the plane of symmetry of an unswept wing and the equations from which the curves were derived are also given. The position of the median plane averaged over the central 30 per cent of the wing span may be found from another three sets of curves, each applying to one value of wing aspect ratio. They are for aspect ratios of 3, 6 and 12 and plot a parameter consisting of the distance of the median plane below the plane of the wing trailing edge divided by the product of the lift coefficient and wing semi-span. That parameter is plotted for various values of wing taper ratio against the distance aft of the wing quarter chord line non-dimensionalised with wing semi-span. Those curves apply in the absence of a fuselage. It is recommended the interpolation for intermediate aspect ratios be made by cross plotting against the reciprocal of aspect ratio. A worked example illustrates the use of the data. Software for the method is provided as Toolbox Aero W.05.01.01 and ESDUpac AW511.