|Authors:||Sorab Panday Motomu Ibaraki Christian D. Langevin Richard G. Niswonger Joseph D. Hughes|
|Resource type:||Model Program Resource|
|Storage:||The size of this resource is 20.4 MB|
|Created:||Aug 28, 2017 at 8:08 p.m.|
|Last updated:|| Aug 29, 2017 at 5:59 p.m.
|Citation:||See how to cite this resource|
A version of MODFLOW, called MODFLOW-USG (for UnStructured Grid), was developed to support a wide variety of structured and unstructured grid types, including nested grids and grids based on prismatic triangles, rectangles, hexagons, and other cell shapes. Flexibility in grid design can be used to focus resolution along rivers and around wells, for example, or to subdiscretize individual layers to better represent hydrostratigraphic units.
MODFLOW-USG is based on an underlying control volume finite difference (CVFD) formulation in which a cell can be connected to an arbitrary number of adjacent cells. To improve accuracy of the CVFD formulation for irregular grid-cell geometries or nested grids, a generalized Ghost Node Correction (GNC) Package was developed, which uses interpolated heads in the flow calculation between adjacent connected cells.
MODFLOW-USG includes a Groundwater Flow (GWF) Process, based on the GWF Process in MODFLOW-2005, as well as a new Connected Linear Network (CLN) Process to simulate the effects of multi-node wells, karst conduits, and tile drains, for example. The CLN Process is tightly coupled with the GWF Process in that the equations from both processes are formulated into one matrix equation and solved simultaneously. This robustness results from using an unstructured grid with unstructured matrix storage and solution schemes.
MODFLOW-USG also contains an optional Newton-Raphson formulation, based on the formulation in MODFLOW-NWT, for improving solution convergence and avoiding problems with the drying and rewetting of cells. Because the existing MODFLOW solvers were developed for structured and symmetric matrices, they were replaced with a new Sparse Matrix Solver (SMS) Package developed specifically for MODFLOW-USG. The SMS Package provides several methods for resolving nonlinearities and multiple symmetric and asymmetric linear solution schemes to solve the matrix arising from the flow equations and the Newton-Raphson formulation, respectively.
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README.TXT MODFLOW-USG - Version: 1.3.00 Three-dimensional, unstructured, finite-difference groundwater flow model NOTE: Any use of trade, product or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. This version of MODFLOW is referred to as MODFLOW-USG in order to distinguish it from other versions of the code. This version of MODFLOW-USG is packaged for personal computers using the Microsoft Windows XP or 7 operating systems. Executable files for personal computers are provided as well as the source code. The source code can be compiled to run on other computers. IMPORTANT: Users should review the file mfusg.txt for a description of, and references for, this software. Users should also review the file release.txt, which describes changes that have been introduced into MODFLOW-USG with each official release; these changes may substantially affect users. Instructions for installation, execution, and testing of MODFLOW-USG are provided below. TABLE OF CONTENTS A. DISTRIBUTION FILE B. INSTALLING C. EXECUTING MODFLOW-USG D. TESTING E. COMPILING A. DISTRIBUTION FILE The following distribution file is for use on personal computers: mfusg_v1_3.zip The distribution file contains: Compiled runfiles and source code for MODFLOW-USG. Supplementary MODFLOW-USG documentation in PDF and text files. Test data sets. The distribution file is a zip file, which can be unzipped to create numerous individual files. The following directory structure will be created when the distribution file is unzipped: | |--mfusg.1_3 |--bin ; MODFLOW-USG executables for personal computers |--doc ; Documentation files |--msvs ; Microsoft Visual Studio Project files |--pymake ; A python script for compiling MODFLOW-USG |--src ; MODFLOW-USG source code |zonebudusg ; Source for zonebudget post processing program |--test ; Input and output files for verification tests |--01A_nestedgrid_nognc; Nested grid test problem |--output ; Results |--zonbudusg; Files for running Zonebudget |--output; Zonebudget Results |--01B_nestedgrid_gnc; Nested grid test problem with gnc |--output ; Results |--zonbudusg; Files for running Zonebudget |--output; Zonebudget Results |--02_quadtree ; **NOT INCLUDED HERE. AVAILABLE AT: ** http://water.usgs.gov/ogw/mfusg/02_quadtree.zip |--arrays ; external arrays needed to run simulation |--input ; model input files |--output ; folder where simulation output will be created |--output_bak; Provided simulation output |--03_conduit_confined |--output ; Results |--03A_conduit_unconfined |--output ; Results |--03B_conduit_unconfined |--output ; Results |--03C_conduit_unconfined |--output ; Results |--03D_conduit_unconfined |--output ; Results It is recommended that no user files are kept in the mfusg.1_3 directory structure. If you do plan to put your own files in the mfusg.1_3 directory structure, do so only by creating additional subdirectories. Included in directory mfusg.1_3\doc are various documentation files. Some of them are Portable Document Format (PDF) files. The PDF files are readable and printable on various computer platforms using Acrobat Reader from Adobe. The Acrobat Reader is freely available from the following World Wide Web site: http://www.adobe.com/ B. INSTALLING To make the executable versions of MODFLOW-USG accessible from any directory, the directory containing the executables (mfusg.1_3\bin) should be included in the PATH environment variable. Also, if a prior release of MODFLOW-USG is installed on your system, the directory containing the executables for the prior release should be removed from the PATH environment variable. As an alternative, the executable files, mfusg.exe and zonbudusg.exe, in the mfusg.1_3\bin directory can be copied into a directory already included in the PATH environment variable. C. EXECUTING MODFLOW-USG Two MODFLOW-USG runfiles for use on personal computers are provided. mfusg.exe is 32-bit version of MODFLOW-USG whereas mfusg_x64.exe is a 64-bit version that may not run on some computers. Bot versions use mixed single and double precision for computations and internal data storage, which was determined to be useful for a wide range of simulations. After the executable files in the mfusg.1_3\bin directory are installed in a directory that is included in your PATH, MODFLOW-USG is initiated in a Windows Command-Prompt window using one of the following commands: mfusg [Fname] or mfusg_x64 [Fname] The optional Fname argument is the name file. If no argument is used, the user is prompted to enter the name file. If the name file ends in ".nam", then the file name can be specified without including ".nam". For example, if the name file is named abc.nam, then the simulation can be run using mixed precision by entering: mfusg abc The data arrays in MODFLOW-USG are dynamically allocated, so models are not limited by hard-coded array limits. However, it is best to have enough random-access memory (RAM) available to hold all of the required data. If there is less available RAM than this, the program will use virtual memory, but this slows computations significantly. Some of the files written by MODFLOW-USG are unformatted files. The structure of these files depends on the precision of the data in the program, the compiler, and options in the Fortran write statement. Any program that use the unformatted files produced by MODFLOW must read the files in the same way they were written. For example, Zonebudget uses unformatted budget files produced by MODFLOW. Current versions of Zonebudget automatically detect the precision of the data in unformatted files and the runfiles provided by the USGS are compatible with the structure of the unformatted files produced by this release of MODFLOW-USG. Another example of unformatted files is head files that are generated by one MODFLOW simulation and used in a following simulation as initial heads. Both simulations must be run using an executable version of MODFLOW that uses the same unformatted file structure. MODFLOW-USG does not automatically detect precision of the data in these files, so both simulations must be run using a runfile having the same precision. This issue of unformatted files is described here so that users will be aware of the possibility of problems caused by unformatted files. D. TESTING Test data sets are provided to verify that MODFLOW-USG is correctly installed and running on the system. The tests may also be looked at as examples of how to use the program. The directory mfusg.1_3\test contains the input data for running each test and the output data, for comparison. The tests are described in the file problems.txt. The directory mfusg.1_3\test can be used to conveniently run the tests without destroying the original results in the MFusg.1_3\test-out directory. The test directory contains MODFLOW name files, which end with ".nam", for running the tests. Each test can be run by executing the run.bat file contained in the folder. E. COMPILING The executable files provided in mfusg.1_3\bin were created using the Intel Visual Fortran compiler. Although executable versions of the program are provided, the source code is provided in the mfusg.1_3\src directory so that MODFLOW-USG can be recompiled if necessary. However, the USGS cannot provide assistance to those compiling MODFLOW-USG. In general, the requirements are a Fortran compiler and the knowledge of using the compilers. The mfusg executable provided here is compiled with the following Intel compiler switches: -O2 -heap-arrays:0 -fpe:0 -traceback
|Programming Language||Fortran 90 with some Fortran 2003 extensions|
|Operating System||Microsoft Windows XP or 7|
|The content of this resource was copied from:||https://water.usgs.gov/ogw/mfusg/|
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