Study on Estimation of Hydraulic Conductivity of Porous Media Using Drag Force Model

Abstract

The resistance is offered when the fluid flows through a porous medium which acts tangentially and perpendicularly to the surface of the media. This resistance offered by the porous mass can be analyzed by evaluating the ease with which water can flow through the porous media, and is expressed in terms of hydraulic conductivity or permeability of the porous medium. It involves a large number of variables such as particle size, its size distribution, shape, porosity and extent of medium. In the present study, experiments were conducted on four different coarse materials namely dolomite, river gravel, marble chips and crushed stones of varying sizes to find out the hydraulic conductivity in the laboratory and also utilizing a semi empirical approach based on the drag force model. Based on this experimental data, a relationship is developed between hydraulic conductivity (k), shape factor (z) and the size of the materials (dg) keeping the porosity constant at 40%. Furthermore, it was observed that hydraulic conductivity obtained from the experimental results tends to give a higher value than those obtainted from this relationship, whereas, those obtained from the model are conservative and tend to approach the experimental values as the size of the material increases.