Author(s):
R.L. Lytton, R. Kher
Publication Date
May 1970
Abstract
This report describes two computer programs for determining changing moisture distribution with time. Program FLOPIP2 is arranged to work one-dimensional problems and computer Program GCHPIP1 solves moisture distribution problems in two-dimensions. The equation governing the flow of moisture is a concentration-dependent, parabolic, partial differential equation which is solved numerically using the implicit Crank-Nicolson method of marching forward in time.|Although it is stable in one-dimensional problems, the Crank-Nicolson method can become unstable in two-dimensional problems, depending upon the relative size of the components of the permeability tensor. This rare form of instability is predicted theoretically and observed in one of the example problems.|Example problems are worked to demonstrate the capabilities and breadth of application of the computer programs and to prove the validity of the approach. The one-dimensional example problems are concerned with matching measured field data and with presenting the results of a parameter study of various suction and permeability factors. The field data can be duplicated to within very close tolerances.|The two-dimensional example problems are arranged to demonstrate the versatility of computer Program GCHPIP1. Problems solved include a two-dimensional consolidation problem, ponding problems, and a problem of predicting moisture distribution within a concrete highway bridge girder.
Report Number:
118-3
Keywords:
compressibility., Computers, Crank-Nicolson method, discrete-element analysis, Expansive Clays, moisture movement, pending, Permeability, Suction, unsaturated permeability
Link(s):
Document/Product
http://library.ctr.utexas.edu/pdf1/118-3.pdf
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