Dealing with an extensive modeling package like FEFLOW, even the most extensive documentation can never answer all the questions a user might have in a specific situation. Furthermore, a long trial-and error process in a commercial project means a considerable loss of time and money.
DHI-WASY offers high-level support given by experienced groundwater modelers to clients with a current maintenance contract for FEFLOW.
Flexible mesh generators
Finite-element discretization allows to use complex unstructured meshes that closely match natural structures while obeying requirements such as element size, element angles, etc. For large modeling areas, generation is supported by sophisticated automation algorithms to ensure efficient work. Automatically generated meshes also have to be adapted to internal geographical structures, like rivers or well locations.
As any single mesh generation approach cannot be expected to perform optimally under all conditions, FEFLOW offers a number of different mesh-generation algorithms and different options of user influence on the generation process.
Transient calculations of complex regional models for long time periods require significant computational effort. Long simulation times can occur, even using the latest hardware available. Parallel processing allows a significant reduction in CPU times on multiple-processor platforms. In FEFLOW tasks of parallel structure as matrix assembly are processed in parallel on the different CPUs.
Spatial discretization of the study area is a prerequisite for any numerical modeling. Classic groundwater simulation codes use finite difference discretization. In contrast, FEFLOW is based on the finite-element technique.
Major advantages of finite-element modeling include:
- Unstructured meshing, thus much better representation of features like rivers, fractures, well locations by adaptation of the mesh
- Better representation of sloping layers and anisotropy
- Local mesh refinement without having to refine the whole column/row
- Moving meshes for free-surface calculations
- Automatic mesh refinement and coarsening
- Less computational effort due to reduced element numbers for large regional models
- Broad range of small-scale and large-scale applications
In most practical applications, the basic spatial data are available either in GIS (e.g., ESRI formats) file format or in a CAD-like format (e.g., AutoCAD exchange format). Direct import of these data formats helps to avoid intermediate conversion routines for transferring the basic data to the groundwater model. In the post processing step, data are easily transferred back to the GIS or CAD system to provide the results in data formats compliant to the project framework. FEFLOW can handle GIS as well as CAD data for import and export at all stages of modeling, e.g., to provide geographical input for mesh generation, parameter distribution, etc. Where appropriate, different regionalization methods are provided to transfer the basic data to the finite elements or mesh nodes. Using GIS files, attribute data can be directly transferred to the groundwater model. Alternatively, all data input can be performed manually or by importing ASCII files.
Up-to-date visualization tools
The days of presenting modeling results in large tables of figures are long gone. Today’s customers expect elaborate isoline maps, pathline diagrams, cross-sectional and 3D views and animations, which can also be used to present complex hydrogeologic conditions to the public.
FEFLOW addresses that need by its planar, cross-sectional and 3D visualization features.
Using FEFLOW three-dimensional visualizations of all model parameters and modeling results (like movements of contaminant plumes, etc.) can be produced.
The equation systems for solving advanced groundwater models result in large matrix systems. To guarantee both stability and effectiveness of the solution, highly sophisticated solvers are required. In FEFLOW, sparse-matrix PCG-type solvers as well as an algebraic multigrid solver are available. There are no internal limitations in the numbers of nodes and elements.
Advanced modeling package
At first glance, it might seem that you won’t need some of the features FEFLOW provides for your every-day work. Nevertheless it is a good decision to choose a scalable sophisticated system with many modeling options.
On the one hand you will be able to work with the same system also for your future applications, which might be quite different from your current modeling tasks. In such a case, it will save time and money if you won’t need additional software and training.
On the other hand, FEFLOW provides many of its easy-to-use high-level modeling features from the inexpensive 2D flow modeling package on. So even if you only deal with relatively simple tasks, you will benefit from the functionality designed to meet the most challenging needs in groundwater simulation.
Companies developing commercial software depend on the satisfaction of their clients: To remain successful, they have to be eager to develop software and documentation according to the client’s needs, to provide a stable and easy-to-use graphical interface, to fix bugs within the shortest time frame possible and to support their clients in software application.
The FEFLOW development team at DHI-WASY has been working on FEFLOW for many years, ensuring the permanent good quality of the product. Close contact between user and developer and latest experiences out of DHI-WASY’s own consulting and research activities are the main basis for successful further development of FEFLOW.
The user of a complex simulation software like FEFLOW requires reliability, accuracy and effectiveness. Physical and mathematical correctness within the limits posed by discretization is essential. All parts of the FEFLOW simulation engine have passed an extensive benchmarking process where results are compared to those of other well-known simulation systems, to analytical solutions or to observations from lab experiments whenever possible. The results of numerous important benchmark tests are published in the documentation, along with a detailed description of the corresponding model setups and an extensive discussion of the results. The related files are available, too. All benchmark examples can be loaded and executed without a license.
Open Programming Interface
FEFLOW covers a broad variety of processes in the subsurface, but still there are very specific applications where its capabilities are not sufficient and the user wishes to modify parts of the system.
For such cases FEFLOW provides an open programming interface to interact with user-specific additional plug-ins. Parameters can be changed at any time, boundary conditions can be varied using external dependencies, time stepping can be influenced, even other programs (like hydrodynamic simulation or parameter estimation software) can be directly linked to FEFLOW. A developer framework provides the basis for designing specific plug-ins. The plug-in can be coded in C/C++ or, using mixed-language programming, in other languages such as Fortran.
So why FEFLOW?
If you still doubt that FEFLOW should be the groundwater modeling package of your choice, try out the free demo version or ask for it at one of the DHI offices, your local distributor or directly at DHI-WASY .
You will understand why.