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Shortcuts with STL Files

With the new FAVORizing function in the Meshing & Geometry tab of the FLOW-3D user interface, users can create an STL file of part or all of their model geometry. This is accomplished by meshing the imported geometry or generated FLOW-3D primitives and then FAVORizing the geometry using the shortcut button on the GUI. Once the FAVORized view is rendered, an STL file of the meshed region (named isofavor0000.stl) is generated in the project directory. The quality of the geometry generated is dependent upon the mesh resolution. For purposes of creating a highly-refined model, a temporary mesh can be drawn, then deleted after the STL file is created.

Modeling Complex Geometries

If a user desires to model a complicated geometry using FLOW-3D primitives and copying subcomponents she has created, appropriate transformations have to be applied to each primitive. In the example given here (Fig. 1), the creation of the fish ladder would be a very tedious task because more than 100 primitives must be created and meticulously transformed with appropriate translations and rotations. Alternatively, the user can create an STL file representing just a part of the geometry using FAVORTM. This file can then be imported back into FLOW-3D to generate the geometry in a new orientation. Figures 2, 3 and 4 briefly show the sequence of steps required to generate the fish ladder using the STL file. This approach can save significant modeling time, because transformations can be applied to an entire portion of the geometry rather than to individual subcomponents that make up that portion. Generally, this shortcut is useful with geometries that involve repeating the use of similar primitives many times.

Figure 1

Figure 1. Fish ladder geometry

Figure 2

Figure 2. Part geometry
and computational mesh

Figure 3

Figure 3. Rendered STL file

Figure 4

Figure 4. Multiple imports and
transformations on the generated STL file

Using STL Files to Initialize a Fluid Region

Users can initialize a fluid region over a topographic geometry by using the STL generation feature in FLOW-3D described above. In the following example, a brief description of fluid or sediment initialization is shown. A topographic file is imported into FLOW-3D and the region of interest (blue) is meshed (Fig. 5). The topographic file is then magnified in the vertical Z-direction. An STL geometry file is obtained using the FAVORIZE function, as shown in Fig. 6. The rendered STL file is then renamed fstl01.inp in the parent directory. Next, using the text editor, a flag was set (ifdis(1)=-1) in the prepin file under the FL namelist (&fl or $fl). This initializes a fluid region above the original topographic file with a depth equal to the magnification used in generating the STL file. The result, Figs. 7 and 8, is a fluid layer conforming to the original topography.

Figure 5

 

Figure 5. Original topographic file
(only the region of interest is meshed).

Figure 6

Figure 6. Magnified STL geometry rendered

Figure 7

Figure 7. Initialized fluid rendered
over the original topographic file

 

 

Figure 8

Figure 8. Height of initialized fluid or sediment above the surface of the topographic geometry