PORFLO-3: A mathematical model for fluid flow, heat, and mass transport in variably saturated geologic media: Users manual, Version 1. 0

Abstract

This manual provides instructions for the use of the PORFLO-3 computer code. This computer code is based on mathematical formulation of fluid flow, heat transfer, and mass transport in variably saturated geologic media. The geologic medium may be heterogeneous and anisotropic and may contain linear and planar features such as boreholes and fractures. The code can be used to analyze three-dimensional problems of partially as well as fully saturated media with various types of fluid, heat, and mass sources. PORFLO-3 is written in American National Standard Fortran 77. A summary of the theory of PORFLO-3 is provided in Chapter 2.0. The three partial differential equations that govern fluid flow, heat, transfer, and mass transport and the method of their solution are discussed. The governing equations are discretized by the method of 'Nodal Point Integration' and solved by any of the four alternate methods: Point-successive Over-relaxation, Alternating Direction Implicit Scheme, Choleski Decomposition, and Gaussian Elimination. The structure of the code and the information flow between its 89 subroutines are explained in Chapter 3.0. Certain practical suggestions for the design of the spatial grid and choice of time steps are discussed in Chapter 4.0. A format-free approach for data input is usedmore » in PORFLO-3. This aspect is discussed in Chapter 5.0 and in Appendix A. Chapter 6.0 provides detailed instructions for data input. Input and output for two example problems are shown in Appendix B. Error messages from PORFLO-3 are listed in Appendix C.« less