Some problems of liquid flow in porous media

In the paper theoretical considerations and results of experimental investigations into a liquid flow in porous media are presented. Since the first experiments with such a flow, made by Darcy in 1856, much research work in this field has been done. The flow of liquid in a porous medium is essentially nonlinear (with the permeability depending on flow velocity). The author reviews the research into this nonlinearity and experimental investigations into a liquid flow in a pore space made in the last 125 years and reports on the experimental investigations into the velocity field in a pore space carried out at the Strata Mechanics Research Institute in Cracow.