Failu krātuve :: MODFLOW-USG/

priede.bf.lu.lv/ftp/pub/TIS/datu_analiize/ModelMuse/MODFLOW-USG

 Name                                  Last modified      Size  Description
 Parent Directory                                           -   
 02_quadtree.zip                       2017-10-24 04:39  107M  Compressed archive
 about.txt                             2017-10-24 04:40  2.2K  Text, ASCII format
 adrese.txt                            2017-10-24 04:40   34   Addresses, URL
 mfusg.1_3.zip                         2017-10-24 04:34   14M  Compressed archive
 release.txt                           2017-10-24 04:34  7.4K  Text, ASCII format
 tm6-A45.pdf                           2017-10-24 04:35  8.4M  Digital document (Acrobat)

MODFLOW-USG: An Unstructured Grid Version of MODFLOW for Simulating 
Groundwater Flow and Tightly Coupled Processes Using a Control Volume 
Finite-Difference Formulation

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.