ESDU 74035 gives curves of trailing-vortex lift-dependent drag factor as a function of taper and aspect ratio@ mid-chord sweep and Mach number. They were obtained using spanwise load distributions calculated by linearised lifting-surface theory. The curves can be applied in all practical cases provided the flow remains fully attached over the wing surface and@ although calculated for straight-tapered wings@ can be applied to other planforms through the use of effective wing parameters for which equations are included.
ESDU 74035 A-1996 history
1996ESDU 74035 A-1996 Subsonic lift-dependent drag due to the trailing vortex wake for wings without camber or twist.