GMS:Building the 3D Mesh from the FEMWATER Conceptual Model

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FEMWATER
Meshgenc.png
Pre-processing
Building a FEMWATER Model
FEMWATER Model Input
Saving a FEMWATER Simulation
Post-processing
FEMWATER Display Options
FEMWATER Post-Processing Viewing Options
Tutorials
FEMWATER Tutorials

Once the FEMWATER conceptual model is constructed, the next step is to use the conceptual model to build a 3D finite element mesh. This is accomplished by first building a 2D mesh, then building the 3D mesh by extruding each of the 2D elements in 3D elements.

Map → 2D Mesh

The first step in building the 3D mesh is to select the Map → 2D Mesh command in the Feature Objects menu. This command creates a 2D mesh by automatically filling in the interior of the conceptual model with nodes and elements. The size and spacing of the elements is controlled by the spacing of the vertices on the arcs and by the refine point attribute assigned to any wells in the interior of the conceptual model.

An example of the Map → 2D Mesh command is shown in the following figure. A sample FEMWATER conceptual model is shown in part a. The 2D mesh resulting from execution of the Map → 2D Mesh command is shown in part b.

File:Meshgenc.gif
Converting a FEMWATER Conceptual Model (a) Conceptual Model (b) 2D Mesh Created with Map → 2D Mesh command (c) 3D Mesh Created by Extruding 2D Mesh (d) 3D Mesh after Map → FEMWATER' command.

Creating the 3D Elements

Once the 2D mesh is created, the next step is to create the 3D mesh by extruding each of the 2D elements into a series of 3D elements. The elevations of the 3D elements can be defined from a set of boreholes, a set of TINs, or a set of Solids.

For sites with relatively simple stratigraphy, the Regions → 3D Mesh command in the Borehole module can be used.

For sites with more complex stratigraphy, the Fill Between TINs → 3D Mesh command in the TIN module should be used.

A mesh can also be created using the Solids → Layered Mesh command in the Solid module.