SWIFT - 3d model to simulate groundwater flow, heat, brine and radionuclide transport

SWIFT Categories: flow models - pathlines/capture zones, fractured systems models, heat transport, saltwater intrusion models, solute transport models - saturated zone
 

SWIFT Description

Three-Dimensional Groundwater Flow and Transport

Pressure, Temperature, Brine, Radionuclides

PC Interface

Dual Porosity and Fractured Media

Introduction to SWIFT
SWIFT Features
SWIFT Basic Assumptions
SWIFT Method of Solution
SWIFT Equations
SWIFT Boundary Conditions
SWIFT Typical Applications
SWIFT Windows Interface
SWIFT STLINE Particle Tracking
SWIFT Runtime Monitor
SWIFT Basic Package
SWIFT Requirements
SWIFT Technical Support

INTRODUCTION TO SWIFT

SWIFT for Windows is a fully transient, three-dimensional model which simulates the flow and transport of fluid, heat (energy), brine, and radio nuclide chains in porous and fractured geologic media. The primary equations for fluid, heat, and brine are coupled with fluid density, fluid viscosity, and porosity. Steady-state options are available for the fluid and brine equations, and both Cartesian and cylindrical coordinate systems may be used. However, the latter system is restricted to two-dimensional, r-z simulations. Both dual-porosity and discrete-fracture conceptualizations may be considered for the fractured zone. Migration within the rock matrix is characterized as a one-dimensional process.

SWIFT FEATURES

• A run-time monitor displays the simulation progress, convergence, mass balance, and dialog.
• Versatile interface to SURFER for contouring pressure, temperature and concentration.
• Extensive error checking.
• Auxiliary files for variable structure grid, restart, mapping, mass balance, well summary and concentration discharge.
• STLINE code for particle tracking.
• Easy installation, 70 verification QA/QC data sets.

SWIFT BASIC ASSUMPTIONS AND CHARACTERISTICS

• Single-phase fluid flow governed by Darcy's law
• Three-dimensional transport in the global system, and one-dimensional transport in the local rock matrix subsystem
• Local rock matrix may be characterized by either prisms or spheres
• Linear variations in porosity and fluid density with respect to the dependent variables
• Viscosity is dependent on temperature and brine concentrations only
• Nonlinear isothermal equilibrium adsorption (Freundlich or linear)
• Injection wastes are miscible with the resident fluids
• Confined or unconfined aquifer (transient or steady-state free water surface)
• Hydraulic and thermal conductivities may be heterogeneous and/or anisotropic
• Longitudinal and transverse dispersivities may vary throughout the domain
• Variable rock compressibility (storativity)
• Dual or simultaneous discretization

SWIFT METHOD OF SOLUTION

Discretization is performed by the finite-difference method using centered or backward weighting in the time and space domains. Matrix solution is performed either by Gaussian elimination or by two-line successive overrelaxation.

SWIFT EQUATIONS

SWIFT comprises the four transport processes: fluid, heat, brine and radionuclide chains. For porous media, only the global (three-dimensional) process simulator is used. For fractured media, the global process simulator is used for the fractured media, and the local (one-dimensional) process simulator is used for the rock matrix.

SWIFT BOUNDARY CONDITIONS

A variety of boundary conditions and source terms may be invoked for both the porous and fractured media. These include:

• Prescribed pressure (head), temperature, and brine concentration
• Prescribed flux of fluid (water), heat, brine, or nuclide mass
• Wellbore injection/production submodel subject to pumping constraints
• Aquifer influence function (i.e., Carter-Tracy infinite reservoir)
• Dual porosity domain extension
• Waste-leach radionuclide submodel for waste repository nuclides and heat
• Freewater surface with recharge

SWIFT TYPICAL APPLICATIONS

SWIFT can be applied to a variety of groundwater problems ranging from simple well flow to complex transport analysis.

• Variable thickness gridding
• Deep well injection of hazardous waste, isothermal/nonisothermal, constant/variable density
• Seawater intrusion
• Optimization of well fields to reduce intrusion and upconing
• Prediction of hazardous waste migration
• Well performance and pumping test analysis
• Complex variable-block elevation and thickness data (input via a separate binary file)

WINDOWS INTERFACE

SWIFT for Windows is a 32-bit application intended for use on the Windows 95/98/2000/NT operating systems. Running SWIFT for Windows is easy with the interface which prompts the user for the data set to simulate, tracks the progress of the simulation and lists the output files created

Postprocessor Interface (UNSWIFT) Contour maps of pressure, temperature, brine, concentration in any window in any plane can be quickly processed directly into uniformly-spaced grid files for the Surfer contouring software.

STLINE Particle Tracking

Allows transient flowpath evaluation of streamlines and export to Surfer as lines or posted symbols.

SWIFT WINDOWS RUNTIME MONITOR

The Windows Runtime Monitor displays essential simulation while the simulation is running. The Windows Runtime Monitor tracks the simulation progress, highlighting the current program activity at the base of the screen. The time step, interval and other data are updated on the screen through the course of the simulation. Below the frame, system RAM requirements, matrix convergence (L2SOR only), creation of map file, and error messages are displayed. Auxiliary files for restart or binary input are also prompted.

SWIFT BASIC PACKAGE

• SWIFT Data Input Guide
• All FORTRAN source code and 70 verification problem input and output data sets on diskettes

SWIFT REQUIREMENTS

Pentium with 32+ MB RAM and Lahey LF95 compiler, and Surfer for postprocessing graphics

SWIFT TECHNICAL SUPPORT

Technical support is limited to installation and initial use. Advice, analysis and suggestions for improvement of model applications and use may be provided only under separate contract. Client confidentiality is maintained.

SWIFT Overview
SWIFT Detailed Description
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