Diffraction of Short Waves by a Contour with a Hölder Singularity of the Curvature. Transition Zone

We consider the short-wave diffraction of a cylindrical wave by a contour whose curvature has a Hölder type discontinuity at a point. The incidence is nontangential at the point of singularity. In the framework of the Kirchhoff method, we find an asymptotic description for the outgoing wavefield inside the transition zone at both small and moderate distances. Analysis of ray formulas allows us to characterize applicability areas of the expressions obtained.