SMS - Surface-Water Modeling System
Surface-Water Modeling System for Windows
SMS is a graphical pre and postprocessor for hydrodynamic modeling which operates on both UNIX- and Windows-based computers. It includes interfaces for the two-dimensional finite-element analysis packages RMA2, HIVEL2D, SED2D-WES, (USACE-WES), FESWMS (FHWA), and the one-dimensional step backwater profiler WSPRO (FHWA). SMS includes the actual models as well as the interfaces.
SMS can be used to interactively create and edit two-dimensional finite-element meshes. Data points can be imported from survey data, digital terrain maps, or created interactively on the screen on top of a background site map or image. Background data can be created from TIFF images or DXF files. The current version of SMS provides a graphical user-interface to the one-dimensional backwater calculation program WSPRO, the two-dimensional hydrodynamic flow simulation programs FESWMS and RMA2, the high-velocity channel-flow simulation program HIVEL2D, the constituent migration simulation program RMA4, and the sediment transport simulation program SED2D-WES. Boundary conditions for all models can be created interactively and assigned to the appropriate region of the mesh. All model parameters are entered through user-friendly dialogs. Resulting water-surface elevations, flow directions and magnitudes, constituent concentrations, sediment depositions, etc., can be displayed in the same environment. Several options for exporting data, including use of the clipboard have been implemented to easily move results form analysis to report documents.
- Microsoft Windows and X-Windows Graphical User Interface.
- Windows 95 and Windows NET compatible.
- Sophisticated tools for creating finite-element networks including adaptive tessellation and patch construction.
- Interactive editing tools for modification of finite-element meshes.
- Interactive creation of boundary conditions for both steady-state and transient conditions.
- Automatic model checker to protect against common user mistakes.
- Creation of FESWMS, HIVEL2D, WSPRO, GFGEN, RMA2, and SED2D-WES input files. All model parameters are entered using user-friendly dialog boxes.
- Import/export of DXF files.
- Use of TIFF images for backdrops (on-screen digitizing) or as texture maps.
- Superior graphics including contour plots, color fringes, shaded images, and ".avi" file generation for transient data.
- Flow trace plots for visualization of complex flow fields and patterns.
- Scatter point interpolation to compare similar meshes.
- Virtual gages for model calibration.
GIS objects can be created by on-screen digitizing from a georeferenced TIFF image. From these feature objects, material boundaries can be defined and meshes can be designated to follow specific feature lines.
Contour Plots can be created from the underlying bathymetry or from the analysis results. Color plots provide a graphical interpretation of analysis results and can be combined with film loops to create animated solutions. Vectors can also be displayed at node locations to enhance visualization.
Flow Traces of the hydrodynamic model results can be created from the analysis data. Flow traces offer a visual representation of how the water will move under various boundary conditions. These and other animations are saved in standard video for Windows format (.AVI). AVI files can then be embedded in presentations or viewed using stand-alone AVI players.
RMA2, hydrodynamic analysis model, computes flow velocities and water-surface elevations at each mesh node. It also computes the dynamic boundary between wet and dry regions in the model. Flow separations and eddy currents are accurately modeled. RMA2, part of the TABS modeling system, has been used extensively by the Army Corps of Engineers and their consultants. Its output can be used by RMA4 and SED2D-WES to model contaminant migration and sediment transport problems.
SED2D-WES, sediment transport model, models the bed scour and sediment deposition for both clay and sand beds. Part of the output includes a modified geometry file for iterative analysis using RMA2.
FESWMS, hydrodynamic analysis model, developed for the FHWA, produces hydrodynamic solutions similar to RMA2. It includes options for easily modeling control structures such as weirs, culverts and bridge piers. It applies to both sub and supercritical flow conditions.
HIVEL2D is a 2-D hydrodynamic modeling code that supports both subcritical and supercritical flow analysis. HIVEL2D was developed by the U.S. Army Corps of Engineers Waterways Experiment Station to model flow in high-velocity channels. HIVEL2D is typically used to predict and analyze flow shock events, such as hydraulic jumps and oblique standing waves, and to determine the super-elevation of the water surface in channel bends. The success of the model to generate accurate predictions depends largely upon accurate water depth specification at both the inflow and outflow boundaries. SMS supports both pre and postprocessing for HIVEL2D.
The WSPRO model is a one-dimensional backwater calculation model designed to compute the water-surface elevations through single and multiple bridge and culvert openings. River stations along the model include topographic data defined as valley cross-sections and flow control cross-sections, such as bridges, culverts, guide banks, and roadways. The model supports both single and multiple opening bridges and culverts, and includes the simulation of piers. Tributary flow may be defined at any cross-section, and multiple flow conditions can be modeled in a single run.
SMS presents the river being modeled as a tree diagram, displaying all cross-section elements along the river. The user may select any cross-section element and graphically edit it. Tools are also provided for copying and modifying cross-sections. In addition, SMS can display the water surface and energy gradeline on both the cross-section plot and profile plot. Also, WSPRO can create up to three user-defined output tables describing the computed modeling results along the river. And, a scour report can be generated - reporting the maximum scour computed at each bridge abutment, pier, and opening.
The SMS interface has been designed in a modular fashion. Five separate modules representing different data types are supported. As you switch from one module to another, the Tool Palette and Menus change to reflect the commands available in the newly selected module. By separating commands in this fashion, you can focus only on the tools and commands related to the module you are currently working on. Switching from one module to another is done instantaneously to facilitate the use of multiple commands and data types for a single project. The following modules are supported in SMS: Meshes, Grids, 2-D Scatter Points, Conceptual Map, and Rivers.
SMS is used to construct two-dimensional finite-element meshes of rivers, bays, or wetland areas where shallow flow occurs. A sophisticated set of automatic mesh generation and mesh editing tools are available in SMS to handle even the most difficult modeling situations. SMS also includes tools for interpolating scattered data to a mesh. This enables the user to compare data from similar meshes or measured data, as well as construct meshes from bathymetric data.
The Mesh Module in SMS contains many operations for interactively creating and editing finite-element meshes. With the continued development of automatic mesh generation tools, the use of interactive tools will decrease, but some still remain as an essential part of the modeling process.
Because no two bathymetric models are alike, SMS has a variety of tools for manual and automatic mesh editing including breaklines, swapping edges, coordinate editing, element refining node relaxing, node insertions, and node or element deletions. The bathymetry of the elements can be contoured or displayed in shaded fringe mode.
The Mesh Module also includes a tool for renumbering or resequencing the elements for efficient numerical operations. The user simply selects a starting point and a renumbering method and SMS renumbers all the nodes and elements in the mesh and reports on the efficiency of the resultant ordering.
The interfaces to the specific models are located in the Mesh Module. This signifies that tools are included to define the model parameters and create boundary conditions specific to any of the models supported by SMS and apply those boundary conditions to individual nodes or nodestrings in the mesh. File I/O for model- specific files is also supported as part of the interfaces included in the mesh module.
Meshes are created using the feature objects data as a guide for creating elements. Bathymetric data is then interpolated to the mesh from a scatter point set. Meshes can be edited directly using interactive mesh editing tools or by modifying the GIS objects and regenerating the mesh.
Future versions of SMS will support finite-grid creation and editing. In anticipation of this, a grid module has been created to provide the framework for tools to create grid regions, insert rows and columns of cells as well as assign properties to individual cells.
Scatter Point Module
The Scatter Point Module is used to interpolate from groups of scattered points to meshes. Data interpolation may serve many useful purposes. For example, a set of scattered data can be created from field data gathered at gages. This data can be interpolated to the mesh and compared with computed data for model calibration. Another example of the use of the scattered data set is to compare two meshes of the same area. A data set can be constructed from an existing mesh. That mesh can then be edited to model a new flow control structure such as a bridge. The solution from the original mesh can then be interpolated to the modified mesh to provide initial conditions. This minimizes the numerical operations required to get to a stable solution. The original results can also be compared to the modified results to determine the affect the modification would have on flow conditions. A variety of interpolation methods are provided with the Scatter Point Module, including Linear, Inverse Distance Weighted, Clough-Tocher, Natural Neighbor, and Kriging.
Feature objects are used in SMS to represent important topographic features such as channel ridges and material zone boundaries. The most time-consuming process in numerical modeling of water ways is the creation of the nodes and elements that comprise the mesh and honor the sites topography. This process is complicated by the fact that multiple sources are used to generate data. Since many features such as flood plain boundaries, water edges, and channel ridges are recognizable on topographic maps, SMS uses feature objects (points, arcs, and polygons) for defining these features. Meshes can be generated "around" these feature objects so as to insure that all arcs are honored by element edges in the resulting mesh.
Four types of objects are supported in the Map Module: DXF objects, image objects, drawing objects, and feature objects.
DXF objects, image objects, and drawing objects are primarily used as graphical tools to enhance the development and presentation of the conceptual model. DXF Objects consist of drawings imported from standard CAD packages such as AutoCAD or MicroStation. Externally-produced site drawings can often provide a useful backdrop or supplement to the graphical desktop during model construction. Drawing Objects are a simple set of graphical tools that allow the user to draw text, lines, polylines, arrows, rectangles, and other symbols to add annotation to the graphical representation of a model. Image Objects are digital TIFF images representing aerial photos or scanned-in maps. TIFF files can be imported and registered to real-world survey coordinates. Construction of the conceptual model can then be accomplished using a high resolution background image. Feature Objects are used to construct the actual conceptual model. Feature objects are patterned after the data model used by geographic information systems (GIS) such as ARC/INFO, ArcView, and MapInfo. The GIS data model utilizes points, arcs (polylines), and polygons to represent spatial information. For example, a point can represent data such as specified head, velocity, and finite element mesh refinement location; an arc can represent flow boundary data such as specified head, flow rate and sediment load; and a polygon can represent areal (i.e., zonal) data such as material type, adaptive tesselation). Sets of points, arcs, and polygons can then be grouped into separate layers or coverages. A set of coverages then provides a complete description of the conceptual model.
Once the conceptual model has been defined, the next step is to develop the numerical model (i.e., 2-D finite element mesh along with interior and exterior boundary conditions) from the conceptual model. If the user decides to change the conceptual model (i.e., adjust a flow boundary, change a material type, adjust the mesh refinement, etc.), these changes can be quickly made to the corresponding conceptual model feature objects and a new numerical model regenerated within seconds.
There are two main advantages to the conceptual model approach. First, generation of the numerical model is much more efficient. The modeler can focus on high level representations of the site rather than on a discretized representation of the site. Thus, data entry is greatly simplified. Second, the overall modeling process is greatly enhanced using the conceptual model approach. If a calibration attempt fails and a modification of the conceptual model is needed, the modification to the conceptual model can be quickly made and a new numerical model regenerated immediately. This makes it possible to evaluate numerous conceptual models quickly and cheaply. As a result, the final numerical model is typically much more accurate.
Most traditional modeling of rivers is done using one-dimensional analysis. SMS is taking the first steps in integrating the use of these methods with topographic models. The river module allows the creation of cross sections of a river. Tools are provided to define bridge openings, culverts, guidebanks and roadways at the cross sections. If a topographic representation of the site has been modeled in SMS, the cross-section information data can be extracted. Tools are also being developed to create a topographic model from a user-defined centerline and the cross-sectional information used by the one-dimensional model. These tools will allow integration of one- and two-dimensional modeling.
Steps for Defining Models in SMS
While no two modeling projects are exactly alike, the typical set of steps used to create hydrodynamic models in SMS consist of the following:
1. Obtain scatter point set of bathymetric data from one of the following sources.
2. Define background mesh by triangulating sampled data if needed.
- Sampled data from external source such as a survey or digital elevation map.
- Digitized points from scanned topographic map.
3. Create a set of feature arcs and points along topographically important features such as channel bottoms and ridges, material region boundaries, flow control structures, etc., in one of the following ways.
4. Define polygons bounding the material zones in the region being represented using the previously-defined arcs.
- On-screen digitizing from a georeferenced TIFF image.
- Conversion from a DXF file.
- On-screen digitizing using the contours from the background mesh.
5. Assign meshing parameters to the polygons, arcs and points.
6. Assign boundary conditions attributes to feature points, arcs, and polygons.
- Specify element-edge size adjacent to each feature point.
- Redistribute vertices along the feature arcs to desired density. Element density in the resulting mesh matches density of vertices along the arcs.
- Assign meshing technique to be either patch or adaptive tessellation for each polygon. Patch parameters will redistribute vertices along the affected arcs.
7. Define material types and assign a material to each feature polygon. Examples of material properties including Manning's n values, eddy viscosities and peclet number.
- Points may be assigned velocities or head values.
- Arcs may be assigned flow, head, or flux status.
- Polygons may be ceiling-elevation functions.
8. Create elements from the polygons, and other feature arcs using the scatter point set to define elevations at the mesh nodes of adaptively tessellated polygons.
9. Examine the mesh for element and mesh quality. Correct mesh errors by either modifying features and repeating Steps 3-7 or edit the mesh interactively by hand. The amount of hand editing should be kept to a minimum due to the fact that it must be repeated each time the mesh is generated.
10. Renumber the mesh to optimize the numerical performance.
11. Assign model parameters such as iteration control, simulation time, model units, output control, etc., for selected model. For FESWMS, this is done using the FESWMS Control Dialog.
12. Define the flow control structures such as piers, culverts and drop inlets. For TABS, this is done using one-dimensional elements. For FESWMS, SMS provides tools to interactively insert flow control structures into the mesh.
13. Run the appropriate model checker.
14. Run the model (FLO2DH or TABS).
15. Import solution file through the data browser and examine the resulting flow field.
Visualization tools include vector plots and contour plots. Check for consistency of computed results with site-measured gage data. Make modifications to material parameters or model parameters if necessary and rerun.
SMS provides utilities for doing all the steps outlined above. The steps are similar for all hydrologic models supported by SMS. Traditionally users have built the mesh interactively instead of utilizing the feature arcs and polygons. This method is still supported.
Windows: PC 386/486/Pentium running Microsoft Windows 3.1/NT/95, math coprocessor, and 4 MB RAM (8 MB recommended).
UNIX X-Windows: AIX, HP-UX, IRIX, OSF, SunOS, SPARC Solaris.
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Τελευταία Ενημέρωση 27 Ιουλίου 2004 - Last Revised on July 27, 2004
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