by Lynn J. Torak
Abstract
Introduction
Background
Purpose and Scope
Design Philosophy for a Modular Approach
Modules and Subroutines
Efficient Use of Computer Storage and Processing Time
Device-Independent Programming
Simulation Capabilities and Versions of MODular Finite-Element Model (MODFE)
Program Structures and Lists of Main Programs
Computational Steps and Subroutines
Programming Details of Linear Hydrologic Terms
Transmissivity
Storage Coefficient
Steady Vertical Leakage
Vertical Leakage of Water Stored Elastically in a Confining Bed
Areally Distributed Sources and Sinks
Point Sources and Sinks
Specified-Head Boundaries
Specified-Flux Boundaries
Head-Dependent (Cauchy-Type) Flux Boundaries
Programming Details of Nonlinear Hydrologic Terms
Water-Table (Unconfined) Conditions
Storage Coefficient (Capacitance)
Transmissivity
Updates to Aquifer Thickness
Conversion Between Confined- and Unconfined-Aquifer Conditions
Aquifer Drying and Resaturation
Head-Dependent (Cauchy-Type) Flux
Point Sinks
Steady Vertical Leakage
Computational Aspects of Simulation Features
Steady-State Flow
Linear Conditions
Nonlinear Conditions
Changing Stresses and Boundary Conditions With Time
Water-Balance Summary and Flow Imbalance
Computational Aspects of Solution Methods
Direct - Symmetric-Doolittle Decomposition
Iterative - Modified Incomplete-Cholesky Conjugate Gradient
Allocation of Computer Storage and Processing Time
General-Storage Vector G
Reduced Matrix A
Reordering Finite-Element Equations for Solution
Condensed Matrix
Solution Methods
References
Appendixes
Variable Lists and Definitions
Fortran COMMON Statements
General-Storage Vector G
Starting-Location Variables in Fortran COMMONIADRI
Conjugate-Gradient Method
Water-Table (Unconfined) Conditions
Nonlinear, Head-Dependent (Cauchy-Type) Flux, Point Sinks, and Steady-Vertical Leakage
Transient Leakage
Main Program
Linear Versions
Transient Leakage
Changing Time-Step Size, Stresses, and Boundary Conditions
Nonlinear Versions
Water-Table (Unconfined) Conditions
Head-Dependent (Cauchy-Type) Flux and Point Sinks
Steady Vertical Leakage
Steady-State Conditions
Direct-Solution Method
Iterative, Conjugate-Gradient Method
List of Subroutines
List of Main Programs