To begin with the 3D Supermesh design, you need firstly to create a new project from File - New. Subsequently, the option Fully unstructured 3D mesh is required to indicate FEFLOW that you build either a 3D Supermesh or import a tetrahedral mesh.
In the wizard, there are three possibilities: Manual domain setup, Supermesh import from maps and FEM mesh import from maps. Only the first two options are relevant for the 3D Supermesh. The third option is used for cases, where a tetrahedral unstructured mesh is already available (e.g., externally created and saved under a VTU format). Here, the mesh will be imported and the steps of 3D Supermesh design and 3D mesh generation will be bypassed.
Building a new 3D Supermesh.
The option "Use new smh3d data structure" enables the latest implementations and developments for 3D Supermeshes in FEFLOW. Deactivating this option will reflect that the Supermesh works with XML format. For all the Geode-Tools available under the Supermesh Processing panel, the new data structure is required.
The Manual domain setup option requires that the user defines the potential extension of the 3D Supermesh. The final extension will be defined during the digitalization of the 3D Supermesh elements at a later stage. The Select coordinate system is optional and will be used to visualize online background maps in the Supermesh only.
Building a new 3D Supermesh: Manual design.
The common case is to build the 3D Supermesh with
a set of external files: New FEM Model
Wizard (
File
menu - New) with the 
Fully unstructured 3D mesh option
and then Supermesh import from maps.
These map files can describe the geometry of surfaces (polygonal or triangulated),
polylines and points.
Building a new 3D Supermesh via external map files.
A 3D Supermesh can be built based on a single map file or a group of map files. The first option will be used typically in situation, where a 3D geological model (structural data) is available. Alternatively, a 3D Supermesh can consist in a set of several map files, which all of them should follow two main requirements:
FEFLOW 10.0 can support a multiple number of file formats, being the most-commonly used below:
Geological models:
Generic 3D Files:
Meshing Files
FEFLOW 10.0 provides the option of storing geometrical information from the imported map files. After each map import, the user can define a Grouping based on By Name or By Attributes options. The option of grouping based on file attributes will read on-the-fly the imported file and allow the user to decide which column in the map file should be used by the grouping. Common groups are created for those topologies, which share the same attribute value.
Depending on the options selected for each imported map file, FEFLOW can import multiple geometries within a single file as one single Supermesh element or group them accordingly to attributes. In the figure below, a map file contains 24 triangulated surfaces, all of them described a fault system. The option on the left side import all the surfaces as one Supermesh element. The option on the right side individualizes the surfaces according to a selected attributed, - in the example below the name.
Building a new 3D Supermesh via external map files: grouping all the surface as one (left) and grouping the surfaces according to a selected attributed (right).
Geometrically-speaking, both options provide the same results; however, the option on the right side with the individualized components adds more flexibility for preprocessing and editing. For example, individual surfaces can be edited or deleted if necessary.
Resulting list of surface using one group for all the surface (left) and an individualization according to a selected attributed (right).
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The entire information used during the Supermesh design (map files, attributes and grouping) can be saved in an external XML-based file named "FEFLOW Supermesh Map Settings" (*.fsms). The file can be used to import Supermesh settings in other projects. The option is supported for 2D and 3D Supermesh projects. |
At the very first instance all the Supermesh Surfaces are disconnected from Supermesh Blocks. FEFLOW considers all the elements as individual entities. The reason is that the connectivity imported by the map files may not be necessarily always correct. Below you can observe an example of a box being split by a plane. Each side of cube and the plane polygon are listed as individual entities under Surfaces in the Meshing panel.
Example of 3D Supermesh elements without any block relationship.
Only the Surface repair under the Supermesh Processing panel allows the individualization of all the Supermesh components. As a consequence of this operation, FEFLOW is aware of proper block definitions and their surface connectivity between the 3D Supermesh project. In the figure below, the Meshing panel shows now two blocks (cube being split by the plane). Each block contains a set of Repaired Surfaces.
Example of 3D Supermesh elements connected to a Supermesh block.
In the case additional elements are included to the 3D Supermesh project, these new entities will not be linked to any of the existing Supermesh Blocks. This approach assures always that the block definition maintains its validity. A subsequent repetition of Surface repair is required to order the newly-create elements to the corresponding block.
Example of 3D Supermesh elements connected to a Supermesh block.
The 3D Supermesh elements can contain a number of properties. In FEFLOW 10.0 the following properties are available:
Blocks:
Element name
Edge size
Material
Surfaces:
Element name
Edge size
Line Add-ins:
Element name
Edge size
Point Add-ins:
Element name
Edge size
The Element name is an optional property and practical to identify multiple elements within the 3D Supermesh project. The name is carried out forward from the 3D Supermesh to the finite-element mesh (FEM problem). The Edge size property is optional and used together with Geode's volumetric mesh generator to control the refinement level at different Supermesh elements. The Material property is used to link the Supermesh blocks to a corresponding Parameter Lookup Material (via Problem Settings - Parameter Lookup Table).
Supermesh properties accessible via the Meshing panel.
After all Supermesh Elements are available within the project, you should make sure that the 3D Supermesh project is free of geometrical inconsistencies such as intersections between surfaces, holes and others. It is not so obvious to identify such as problems by simply visually inspecting the geometries. You can test the validity of the 3D Supermesh project by trying to generate a tetrahedral mesh with TetGen or Geode with the Meshing panel. Geometrical problems will be detected by the generators and the operation will be aborted.
The effort of repairing the 3D Supermesh depends on the complexity of the geometries, levels of details (e.g., refinement level of the surfaces) and others. FEFLOW offers the Surface repair tool accessible via the Supermesh Processing panel to solve geometrical intersections between surfaces.
In the example below on the left side, you can clearly observe that the 3D Supermesh contains a set of faults fully intersection with the 3D boundary. Such as configuration cannot be meshed. The Surface repair algorithm identifies the intersections and repairs the 3D Supermesh with new triangulations. A resulting example is shown on the figure below (right side).
Resulting list of surface using one group for all the surface (left) and an individualization according to a selected attributed (right).
For further details on how to preprocess a Supermesh, please refer to the section 3D Supermesh Preprocessing.