Find Gaps

Use the Find Gaps tool to provide feedback regarding unresolved gaps in the model.

Unresolved gaps are defined as regions in the model where there is only a single fluid voxel spanning the gap between two partial or solid voxels. When this situation occurs, uFX may produce unrealistic results. To ensure that reliable results are achieved from the areas of interest, you should ensure that there are no significant unresolved gaps. The gap finder is intended to assist with this.

The Find Gaps tool works by performing a portion of the meshing process on the current model. At the conclusion of meshing, the mesh is loaded into VWT and interrogated to find the regions that represent a gap. The gap cells are then displayed in VWT for you to review. If large gap regions are identified, the mesh can be refined in the area of interest to resolve it better, or the mesh can be coarsened to treat the gap region as solid.

Run the Gap Finder

Run the gap finder utility for the given mesh controls.

Note: The meshing process relies on running the ultraFluidX executables. Therefore, this part of the workflow is only supported on Linux platforms.
  1. Define mesh controls.
  2. From the ultraFluidX ribbon, Setup group, click the Run Gap Finder tool.
    Figure 1.
    The Find Gaps dialog opens.
  3. Optional: Enter a case name.
  4. Choose a directory to write the output to.
  5. Run the gap finder.
    Option Description
    On Windows Platforms
    1. Click Export.
    2. Copy the .xml and .stl files that were created in the output directory over to a Linux system.
    3. On the Linux machine, run the basic_mesh utility using the ufxRun script, located in the uFX installation in the scripts directory:

      $INSTALL_DIR/.altair/hwx/bin/linux64/ufx/scripts/ufxRun -pb Gap_1 -inp Wind_tunnel.xml -do basic_mesh

    4. Once ufxRun completes, you will have .case, .geo, and .data files present in the run directory. Copy these over to the Windows machine then click Import in the Find Gaps dialog to load them into VWT.

      At this point, VWT interrogates the mesh to find the gap regions and they can be viewed in the gap display context.

    On Linux Platforms
    1. To delete the generated mesh files after a successful run, activate the Delete intermediate files option.
    2. Click Run.

      The Gap Finder Run Status dialog opens.

Review Gaps

Visualize unresolved gaps found by the gap finder.

  1. Do one of the following:
    • From the ultraFluidX ribbon, Setup group, click the Find Gaps tool to display the gap regions of the most recent run.


      Figure 2.
    • From the ultraFluidX ribbon, Setup group, click the Find Gaps tool satellite icon. In the Gap Finder Run Status dialog, double-click on a run, select a run and click the View Now button, or right-click and select View Now.


      Figure 3.
  2. Use the legend in the top-left of the modeling window to review the found gaps.


    Figure 4.
Tip: Right-click on a run in the Gap Finder Run Status dialog and select Open Run Folder to view the results in the output directory.

Review Gap Mesh

Isolate, export, rename, delete, and change the display color of the gap mesh.

  1. If the gap mesh is not currently displayed, from the ultraFluidX ribbon, Setup group, click the Find Gaps tool.


    Figure 5.
  2. Use the legend in the top-left of the modeling window to review and edit the gap mesh.
    • Click Isolate to review a specific mesh then click All to return to the default view.
    • Right-click on a mesh in the legend and select Change Color to select a new color display color.
    • Right-click on a mesh in the legend and select Export to export the gap cells in a .nas file.
      Note: This differs from the clicking Export option in the Find Gaps dialog, which exports the input files needed to run the meshing process.
    • Rename a mesh by double-clicking on an option in the legend, entering a new name, and pressing Enter.
    • Right-click on a mesh in the legend and select Delete to remove it.

Delete Gap Finder Runs

Remove files in your output directory for select gap finder runs.

  1. From the ultraFluidX ribbon, Setup group, click the Find Gaps tool satellite icon.


    Figure 6.
    The Gap Finder Run Status dialog opens.
  2. Select a run.
  3. Do one of the following:
    • Click Delete.
    • Press the Delete key.
    • Right-click and select Delete.
    The files for the run are removed from your output directory.