Blasius–Chaplygin formula

The Blasius–Chaplygin formula, devised by Sergey Chaplygin from the work of Heinrich Blasius relates the force ${\bar {L}}$ given by a complex velocity field $f$

${\bar {L}}={\frac {I\rho }{2}}\int _{\gamma }f^{2}(z)\,\mathrm {d} z$

The equation stated above appears from the analysis of the velocity over a body with a boundary $\gamma$, taking Bernoulli's law into consideration.