Certain problems of motion of incompressible visco-friable materials

The steady motion of an incompressible visco-friable medium is considered. Equations of motion in the boundary layer are obtained and the flow over a flat plate is investigated. The flow in a plane diffuser and between rotating cylinders is analyzed.     

Percolation models of the permeability properties of media

Models that describe the permeability of media with allowance for the structure of the pore space are considered. It is proposed to use percolation theory to describe the topology of the pore space. If the distribution of the pore channels in the medium is random, percolation theory makes it possible to determine the percolation threshold, and also to estimate the fluid conductivity of the cluster that then results. Results obtained for models of granular, porous, and cracked media are given.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 3, pp. 81–86, May–June, 1984.