Simulation of SurfaceWater Integrated
Flow and Transport in Two Dimensions:

A numerical model for simulation of surfacewater integrated flow and transport in two (horizontalspace) dimensions is documented. The model solves vertically integrated forms of the equations of mass and momentum conservation and solute transport equations for heat, salt, and constituent fluxes. An equation of state for salt balance directly couples solution of the hydrodynamic and transport equations to account for the horizontal density gradient effects of salt concentrations on flow. The model can be used to simulate the hydrodynamics, transport, and water quality of wellmixed bodies of water, such as estuaries, coastal seas, harbors, lakes, rivers, and inland waterways. The finitedifference model can be applied to geographical areas bounded by any combination of closed land or open water boundaries. The simulation program accounts for sources of internal discharges (such as tributary rivers or hydraulic outfalls), tidal flats, islands, dams, and movable flow barriers or sluices. Waterquality computations can treat reactive and (or) conservative constituents simultaneously. Input requirements include bathymetric and topographic data defining landsurface elevations, timevarying water level or flow conditions at open boundaries, and hydraulic coefficients. Optional input includes the geometry of hydraulic barriers and constituent concentrations at open boundaries. Timedependent water level, flow, and constituentconcentration data are required for model calibration and verification. Model output consists of printed reports and digital files of numerical results in forms suitable for postprocessing by graphical software programs and (or) scientific visualization packages. The model is compatible with most mainframe, workstation, mini and microcomputer operating systems and FORTRAN compilers. This report defines the mathematical formulation and computational features of the model, explains the solution technique and related model constraints, describes the model framework, documents the type and format of inputs required, and identifies the type and format of output available.
Abstract
Introduction
Model Applications
Purpose and Scope
SWIFT2D Model Overview
Governing Equations
FiniteDifference Approximations
Solution Technique
Special Computational Features
Model Implementation Process
Simulation Data Requirements
Model Limitations and Program Considerations
SWIFT2D Simulation Process
SWIFT2D Program Structure
Simulation Setup
Interactive FileDesignation Procedure
SWIFT_IDP Execution
SWIFT2D Execution
Run Log File
Restart File
Emergency Restart Files
Hardware and Software Requirements
Computer Memory
Run Time
SWIFT2D Input
InStream Input
Simulation Input File
Part 1 Input
Part 2 Input
Part 3 Input
Part 4 Input
SWIFT2D Numerical Aspects and Computational Features
Sequence of Operations
Rectangular Grid Layout
Cell Size
Location of Variables
Computational Grid Enclosure
Default Enclosure
Complex Enclosure
Boundary Openings
Time Step
Time and Space Interpolation
Integration Options
Time Smoothing
Drying and Flooding
Permanently Dry Points or Dams
Chezy Coefficients
Marginal Depth Values
Functions of Salinity Gradient
Forcing Functions
Fourier Tide Openings
SpaceVarying Wind and Pressure
Constituent Concentrations at Open Boundaries
Barriers
Condition 0
Condition 1
Condition 2
Condition 3
Condition 4
Conditions 5 and 6
Condition 7
Condition 8
Particle Tracking
Transport and WaterQuality Simulation
SWIFT2D OUTPUT
Printed Output
Error, Warning, and Run Messages
Override Messages
Dimension Messages
Restart Messages
Emergency Restart Messages
History File Messages
Run Messages
Data Messages
Final Messages
History File
Map File
CoarseGrid File
Summary
Acknowledgments
References Cited
Appendix 1. SWIFT2D InStreamInput Record Format
Appendix 2. SWIFT_IDP Program and Input Description
Appendix 3. Sample SWIFT2D InStreamInput (*.ctl) and SWIFT_IDP Input (*.idp) Files
1–3. Flowcharts showing:
1. The processing of data and files associated with SWIFT2D
2. The preprocessing of data and files associated with SWIFT_IDP
3. Files associated with SWIFT2D execution
4. Computational procedure in SWIFT2D
5. Location of variables on SWIFT2D staggered grid
6. Default computational grid with arbitrary openings
7. Computational grid enclosure angles
8. Computational grid enclosure lines
9. Computational grid enclosure polygons
10. KBO codes defining type, location, and orientation of boundary opening
11. Typical barrier between two dam points
12. Barrier in two flow directions at a single grid point
13. Five basic flow conditions for a barrier
14. Sample plot of SWIFT2D simulated particle excursions in the Potomac Estuary
1. Typical contents of the SWIFT2D.MTR file
2. Typical contents of the SWIFT_IDP.MTR file
3. Typical contents of the IDPRUN.LOG file
4. SWIFT2D files
5. Typical contents of the SWIFTRUN.LOG file
6. Relative speed of various computers executing SWIFT2D
7. Instreaminput record order
8. Part 1 variables that cannot be overridden
9. Part 1 variables that produce a warning message if overridden
10. Part 1 variables input order and override checklist
11. Part 1 input record order
12. Definition of Part 1 input variables
13. Part 2 input record order
14. Part 3 input record order
15. Primary computational routines in SWIFT2D
16. Important arrays in SWIFT2D
17. Time step of variable computation
18. Relation of variables in integration options
19. Variable definitions common to equations 11–15
20. Criteria for Chezy coefficient computation, drying, and flooding
21. KBO codes for defining boundary conditions
22. Flow direction of concentration computations at open boundaries
23. Symbols used in barrier history printout
This report is presented in Portable Document Format (PDF).
Printable tabloid cover (5.7 MB)1 page
Left inside cover (35 KB)1 page
Report (606 KB)124 pages
The citation for this report, in USGS format, is as follows:
Schaffranek, R.W., 2004, Simulation of surfacewater integrated flow and transport in two dimensions: SWIFT2D user's manual: U.S. Geological Survey Techniques and Methods, 6 B1, 115 p.
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Persistent URL: Page Contact Information: Contact USGS Last modified: Friday, December 02 2016, 03:43:45 PM 