Creeping waves and resonances in transient scattering by smooth convex objects

摘要: Scattering by smooth convex objects, excited a transient field with broad spectral content, has been analyzed either ray formulations, which are useful at observation times descriptive of the early arrivals, or complex resonances singularity expansion method (SEM), most appropriate intermediate and late times. Within framework SEM, efforts have recently made to show that in grouping along "layers," rather than conventional "arcs" based on an angular harmonic representation, higher order behave collectively like wave traveling circumferentially around object. This provided stimulus for present investigation relation between wavefront arrivals (creeping waves) SEM is placed rigorous basis. Using perfectly conducting circular cylinder as canonical model, this done direct application theory characteristic Green's functions construct alternative solutions, collective summation groups resonances. The connection creeping waves thus having established, hybrid formulations developed combine within single so maximize utility each over entire range These results then generalized cylindrical objects noncircular shape.