Energy fluxes and resonances in waveguides with obstacles

Semi-analytical approaches to building low cost computer models of elastic wave excitation, propagation and diffraction phenomena related primarily to seismoacoustics and nondestructive testing, are developed. These methods are quite applicable to the electromagnetic wave propagation problems as well. The main features ensuring their high efficiency are outlined. The authors examine how the shape of a crack influenced the reflected field (the scattering cross section, scattering patterns, power redistribution) and the location of the scattering resonances in the complex frequency plane. A possible use of the obtained dependence of the resonance poles against the scatterer shape and size for regularisation of the ill-posed inverse problems is discussed.