S.Y. Belonogov, V.G. Gavrilenko, M.S. Zhukov, V.A. Yashnov

The propagation of incoherent waves in a planar waveguide, the boundary surface of which contains large smooth gentle irregularities on the scale of the wavelength is considered. The problem is solved by numerical statistical modeling by the corpuscular method of Monte Carlo, modified to account for the scattering and diffraction of surface irregularities. The shading of surfaces irregularities is shown to lead to a significant decrease in the average energy density at the observation point. In presence of shadows, waves diffraction was found to have a significant effect of noticeably increasing energy density with rising wavelength due to the penetration of waves by the diffraction in the geometric shadow. It is shown that the height increase of random roughness of the boundary surfaces, all other things being equal, reduces the average energy density of the wave field in a waveguide with partially absorbing boundaries.