Excerpt from Simulating Water Flow in Soil: With an Electrical Resistance Network

Water infiltration, redistribution, and removal from soil are important processes that affect all land management systems. Although these processes must be studied under field and laboratory conditions, certain phases can be evaluated by analog techniques with a considerable saving in time and cost and in accuracy. Electrical analogs have been very useful in these evaluations. Two types have been used - with good success: (1) those utilizing the flow of electricity through sheets of electrical conducting paper and (2) those using a network of electrical resistors. Electrical conducting paper can be used to solve steady-state flow problems in porous media that are saturated, isotropic, and homogeneous With respect to its hydraulic conductivity. An electrical re sistance network is more flexible in its use than conducting paper. The network can quickly be adjusted to simulate flow conditions in soils that are homogene ous or stratified, saturated or unsaturated, isotropic or anisotropic. Various investigators have already utilized the network to study flow of water either in homogeneous or stratified medium (1, 6, 7, In this report, the major objective is to present a method for calculating and assembling network resistances to represent water flow in soil. The ap proach used herein is called the building block method. The soil profile is considered to be composed of discrete, rectangular blocks of soil. These blocks are then joined to build the entire soil profile. Each block of soil is represented by a mesh of four resistors. The meshes are then joined to form the network, which, in turn, represents the soil profile. The discussion in this report will deal with representations of steady-state flow of fluid in saturated and unsaturated media. Procedures will be given for representing media that are either homogeneous or stratified and either isotropic or anisotropic with respect to soil hydraulic conductivity. Formulas will be given for calculating resistances when rectangular blocks of different dimensions are used. Special formulas are presented for calculating resistances adjacent to a tubular drain embedded in the soil.

About the Publisher

Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com

This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.