|  | Simulation of Surface-Water Integrated          Flow and Transport in Two Dimensions:        SWIFT2D User’s Manual U.S. Geological Survey Techniques and Methods 6 B-1 By Raymond W. Schaffranek |
|--|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

ABSTRACT

  A numerical model for simulation of surface-waterintegrated flow and transport in two (horizontal-space)dimensions is documented. The model solves verticallyintegrated forms of the equations of mass and momentumconservation and solute transport equations for heat, salt, andconstituent fluxes. An equation of state for salt balance directlycouples solution of the hydrodynamic and transport equationsto account for the horizontal density gradient effects of saltconcentrations on flow. The model can be used to simulate thehydrodynamics, transport, and water quality of well-mixedbodies of water, such as estuaries, coastal seas, harbors, lakes,rivers, and inland waterways. The finite-difference model canbe applied to geographical areas bounded by any combinationof closed land or open water boundaries. The simulationprogram accounts for sources of internal discharges (such astributary rivers or hydraulic outfalls), tidal flats, islands,dams, and movable flow barriers or sluices. Water-qualitycomputations can treat reactive and (or) conservativeconstituents simultaneously. Input requirements includebathymetric and topographic data defining land-surfaceelevations, time-varying water level or flow conditions atopen boundaries, and hydraulic coefficients. Optional inputincludes the geometry of hydraulic barriers and constituentconcentrations at open boundaries. Time-dependent waterlevel, flow, and constituent-concentration data are required formodel calibration and verification. Model output consists ofprinted reports and digital files of numerical results in formssuitable for postprocessing by graphical software programs and(or) scientific visualization packages. The model is compatiblewith most mainframe, workstation, mini- and micro-computeroperating systems and FORTRAN compilers. This reportdefines the mathematical formulation and computationalfeatures of the model, explains the solution technique andrelated model constraints, describes the model framework,documents the type and format of inputs required, and identifiesthe type and format of output available.

CONTENTS

Abstract

		    Introduction

		    Model Applications		  

		    Purpose and Scope		  

		    SWIFT2D Model Overview		  

		    Governing Equations		  

		    Finite-Difference 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 File-Designation Procedure		  

		    SWIFT_IDP Execution		  

		    SWIFT2D Execution

		    Run Log File

		    Restart File

		    Emergency Restart Files

		    Hardware and Software Requirements		  

		    Computer Memory		  

	      Run Time

SWIFT2D Input		  

		    In-Stream 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

		    Space-Varying 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 Water-Quality 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		  

		    Coarse-Grid File		  

		    Summary		  

		    Acknowledgments		  

		    References Cited		  

		    Appendix 1. SWIFT2D In-Stream-Input Record Format		  

		    Appendix 2. SWIFT_IDP Program and Input Description		  

Appendix 3. Sample SWIFT2D In-Stream-Input (*.ctl) and SWIFT_IDP Input (*.idp) Files

## FIGURES 

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

## TABLES 

 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. In-stream-input 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

 

----

## AVAILABILITY

This report is presented in Portable Document Format (PDF).

Toview and print report you will need to use PDF Viewer or Adobe Acrobat Reader (available as freeware)

Users with visual disabilities can visit this site for conversion tools and information to help make PDF files more accessible
 

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 surface-water integrated flow and transport in two dimensions: SWIFT2D user'smanual: U.S. Geological Survey Techniques and Methods, 6 B-1, 115 p.*
AccessibilityFOIAPrivacyPolicies and Notices
U.S. Department of the Interior, U.S. Geological SurveyPersistent URL: http://pubsdata.usgs.gov/pubs/tm/2005/tm6b1/		Page Contact Information: USGS Publishing NetworkLast modified: Friday, December 02 2016, 03:43:45 PM