Viviand showed, after lengthy calculations, that the lift coefficient is given by
Here we substituted ф for єф1. This result is consistent with the Kutta-Joukowski lift theorem. Indeed, if one considers a section dy of the wing with bound vorticity Г(y), the element of lift is
dL — p^U Г (y)dy
and is perpendicular to the incoming flow. The total lift will be
and the lift coefficient based on the reference area Aref given by the above formula.