We investigate a model of gravitational collapse matter inhomogeneities where the latter are modelled as Bianchi type IX (BIX) spacetimes. found that this contains, limiting cases, both standard spherical and Zeldovich solution for 1-dimensional perturbation. study how these models affected by small anisotropic perturbations within BIX potential. For case, we is equivalent to closed FLRW Univer...

The waves (including acoustic, electromagnetic and elastic ones) propagating in the presence of a cluster inhomogeneities undergo multiple interactions between them. When these have sub-wavelength sizes, dominating field due to is Foldy–Lax field. This models equivalent point-like scatterers, located at centers small inhomogeneities, with scattering coefficients related geometrical/material pro...

An approximation technique is considered for computing transmission and reflection coefficients for propagation of an elastic pulse through a planar slab of finite width. The propagation of elastic pulse through a planar slab is derived from first principles using straightforward time-dependent method. The paper ends with calculations of enhancement factor for the elastic plane wave and it is s...