Spatial motion of interface of two heavy viscous fluids in a porous medium

The integrodifferential equation for the spatial motion of the interface of two fluids of differing weights and differing viscosities in a porous medium is presented. Results of its numerical solution are given. The general solution is given for the problem of the dynamics of a gently sloping surface.The author wishes to thank V. L. Danilov for his interest in the study and valuable advice.