Paradox of the blunt edge of an airfoil in an unsteady flow

A paradox of the blunt edge of an airfoil in an unsteady ideal flow is established, which states that the solution of the nonlinear problem of unsteady flow around a blunt-edged airfoil subject to strict boundary conditions at this edge is physically meaningless. The paradox is a consequence of the adopted model of the unsteady fluid flow near the blunt edge, which assumes inflection of streamlines. It is established that the solution of the problem by local replacement of the blunt edge by a sharp edge using the hypothesis on the smoothness of streamlines near the trailing edge is physically meaningful.