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| AIR/W - Air flow analysis. |
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AIR/W is a finite element software product for analyzing groundwater-air interaction problems within porous materials such as soil and rock. Its comprehensive formulation allows you to consider analyses ranging from simple, saturated steady-state problems to sophisticated, saturated-unsaturated time-dependent problems. You can apply AIR/W to the analysis and design of geotechnical, civil, hydrogeological, and mining engineering projects.
AIR/W can be applied to both saturated and unsaturated zones, a feature that greatly broadens the range of problems that can be analyzed. In addition to traditional steady-state water flow assumptions where the air contents are fixed, the saturated/unsaturated formulation of AIR/W makes it possible to analyze air flow and seepage as a function of time and to consider such processes as changing air and water contents. When linked with TEMP/W, it can account for air and water flow in freezing and thawing soils where the air density changes due to temperature changes. Easy to Use
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Defining a Seepage/Air flow Model
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The unique CAD-like technology in AIR/W allows you to generate your finite element mesh by drawing regions on the screen. You can then interactively apply boundary conditions and specify material properties. You can even estimate the material property functions from easily measured parameters like grain-size, saturated conductivity, saturated water content, and the air-entry value. If you make a mistake, you can correct it using the Undo command.
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Viewing the Analysis Results
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Once you have solved your seepage problem, AIR/W offers many tools for viewing results. Generate contours or x-y plots of any computed parameter, such as head, pressures, matric suction, gradients, velocities, and conductivities. Air or water velocity vectors show flow direction and rate. Transient conditions can be shown as the changing water table position over time. Interactively query computed values by clicking on any node, Gauss region, or flux section. Then export results into other applications, such as Microsoft Excel or Word, for further analysis or to prepare presentations.
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Typical Applications
AIR/W can model almost any groundwater problem, including:
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Soil vapor extraction systems
Air pressure in tunnels for support and water inflow control
Air pressure response ahead of water infiltration fronts
Thermal / density dependent air flow that contributes to convective heat transfer in freezing / thawing soils (when coupled with TEMP/W)
The true matric suction (Ua-Uw) phenomenon
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| Formulation |
Soil Properties
The hydraulic conductivity of the soil is a function of the negative pore-water pressure in the unsaturated regions. The rate of change in water content is dependent on the pore-water pressure during transient processes. Hydraulic conductivity can be defined as anisotropic in two orthogonal directions.
Iterative Process
The nonlinear nature of the finite element equations is handled using an efficient radial search iterative scheme. Graphing tools are available during run-time to help you judge if convergence has been achieved. This has proved to be extremely useful in solving highly nonlinear flow systems.
Flux Quantities
AIR/W computes the total flux across single or multiple lines drawn through the mesh.
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| Features: |
- Analysis types include steady-state confined and unconfined flow, transient flow, 2-D flow in a cross-section or in plan view, and 3D axisymmetric flow.
- Boundary condition types include total head, pressure head, or flux specified as a constant or a function of time; pressure head; transient flux as a function of computed head; review and adjustment of seepage face conditions.
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- Volumetric water content and conductivity functions can be estimated from basic parameters and grain-size functions.
- Adaptive time stepping to ensure the use of optimal time steps in transient analyses with sudden changes in boundary conditions.
- Flow path deliniation.
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| Use AIR/W data in TEMP/W |
AIR/W and SEEP/W integrate with TEMP/W so that you can model convective heat transfer due to moving air and water. Conversely, you can have the thermal solution affect the air densities and pressures in AIR/W so that the air will flow based on thermal processes alone. AIR/W passes air content and mass flow vectors to TEMP/W and it returns the new temperature profile to AIR/W. All of this happens automatically based on your analysis type definition.
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Engineering Methodology Book |
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When you purchase an AIR/W 2007 license you also receive a copy of the AIR/W Engineering Methodology book, Air Flow Modeling with AIR/W 2007. This book is not a software manual but a full-length book that discusses why and how to model. It does not describe how to use the commands in the software or which buttons to click - that is provided in detail in the Online Help. Instead it is about thinking: how to think before, during and after setting up and solving a model. The Engineering Methodology book has chapters devoted to: |
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Material Models and Properties
Bounday Conditions
Analysis Types
Functions in GeoStudio
Numerical Issues
Visualization of Results
Modeling Tips and Tricks
Illustrative Examples
Theory
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| Helping Communities |
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Project Review
Ecoseal reviewed the ACIAR Project on Sustainable Agriculture in Saline Environments through Serial Biological Concentration, which was carried out in Pakistan and Australia. |
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| Read More |
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Seawater Intrusion Model for the Island of Kayts, Sri Lanka
Assessing sustainable water supply options for Kayts to limit the impact of saline groundwater upconing and saltwater intrusion along the northwest coast of Sri Lanka. |
| Read More |
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Groundwater Management Model for the Lower Murray, Australia
The aim of this project was to develop a groundwater management model which was used by natural resource managers and the community to better manage the groundwater resources of the Lower Murray. This region has been designated as a potential high-risk aquifer system.
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| Read More |
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