Detailed Features of SVAirFlow 2D

SVAirFlow implements a comprehensive list of features which are outlined as follows:

Simulation Features

• Soil properties may vary with soil region.
• Unsaturated zones of soils may be modeled.
• Initial conditions may be imported from a previous analysis.
• Finite element analysis by the Galerkin method. The solver uses advanced features such as preconditioning of the convergence matrix as well as staging and automatic mesh refinement to achieve solutions with greater stability than any other software currently available.
• Solver runs on Red Hat Linux or Windows with support for hyper-threading and multiple processors.
• Anisotropic analysis at any angle in 2D or 3D.
• Axisymmetric analysis.
• Fully automatic mesh generation. Mesh generation may be limited by a maximum number of nodes or by a maximum specified error.
• Fully automatic mesh refinement. Mesh refinement is based on the relative error of the governing equation and therefore automatically locates critical zones. Mesh refinement may be specified to follow any particular variable in the problem. In a transient analysis a different mesh is generated for each time step. SVAirFlow is currently the only soil vapor extraction package in the world to offer this feature. Read more about adaptive grid refinement in research published by Mansell, 2002.

Model Design Features

• CAD-style entry of geometry.
• Grid, snapping, and object snapping features available.
• Zooming, panning features available.
• Import AutoCAD .dxf geometry and incorporate it directly in the model. The automatic mesh generation will automatically allign node points with line segment end points.
• Graphically assign boundary conditions.
• Air pressure or flow boundary conditions may be specified. Free form equations may be specified as a function of position (i.e. p=0.5+log(x)*0.1)
• Problems may be entered in Metric or Imperial units
• All aspects of all models are stored in a database which may be placed on a server. Multiple users may be "plugged in" to the same modeling database.
• Water contents may be imported from an SVFlux analysis.
• A central database of soil properties for all entered air-flow problems is maintained. New problems may draw soils from existing problems.
• Problem geometry may be imported from existing problems.
• Existing problems may be saved under a new name in the database to allow quick generation of multiple scenarios.
• Colors or patterns of soil regions may be specified.
• Manual entry of region coordinate points.
• Lines may be added to model to force mesh refinement along a linear object.
• Internal boundary conditions may be set or node density specified along internal line objects.
• Sketch text or lines may be added to the model design.
• Graphical model design may be exported as a WMF or DXF file and/or printed.
• Bitmap or DXF geometry may be imported and layered behind model geometry to simplify model creation.

Output Features

• Color contour plots of all relevant stress variables. Custom color shadings may be specified.
• Plots may be zoomed to isolate any region of interest.
• Vector plots of pressure gradients may be produced.
• Volume integrals may be computed over the entire problem or any particular region of interest.
• Mesh plots track mesh refinement.
• Plots of value versus time may be generated at any coordinate for all relevant variables.
• Surface plots of any 2D variable over the problem region may be produced.
• Overlaying of plots may be performed. For example, vectors may be shown in Region 1 while contours of head may be shown in Region 2.
• Text and line art may be added to output.
• Graphical output may be exported to WMF, DXF, JPG, or BMP formats.
• Transient results may be animated.

Applications

• Vapor extraction calculations in 2D and 3D.
• Vapor flow into foundations.

Documentation

The following manuals document the operation of the SVAirFlow software. The design of the software makes it simple to learn and use. Most users are able to learn how to use the software effectively to create 2D problems within 30-60 minutes.

• User's manual - documents specific operation of software (pending).
• Tutorial manual - Step-by-step instructions guide the user through creation of 2D and 3D problems (pending).
• Theory manual - documents the theory of the governing partial differential equations used in the solution of the seepage problem (pending).
• Verification manual - benchmarks the SVAirFlow software against typical seepage problems published in texts, journal papers, or manuals from other software packages (pending).

System Requirements

• SVAirFlow2D runs on Windows 95/98, NT 4.0, Me, 2000, and XP. The recommended minimum hardware configuration is a P266 with 128MB RAM and 35 MB hard disk space.