After you have generated a volume mesh, you can add the Choose Part Replacement Options task to your workflow to replace, add, or remove portions of you original imported CAD geometry. This can be useful in studying mesh differences (or flow field changes) due to geometric differences introduced to your CAD model (for example, replacing mirrors, fenders, or spoilers on an automobile). Part replacement can also be combined with introducing translations, rotations, etc for your CAD parts.
You can use this task to avoid re-importing multiple, subtly different CAD geometries and performing the individual workflow tasks on separate CAD models. Using this task in the workflow, once any parts are replaced, you can very easily and quickly update the volume mesh to see the results of your changes.
Use the Do you need to append parts? prompt to determine whether or not you are going to add any parts to your original geometry. Selecting Yes will create a new Append CAD and Part Management task that you can use to append new CAD part(s) to the existing CAD model. This new task is a replica of the original task in the workflow where you can import any additional parts that you want to use as replacement parts. See Appending Replacement Parts for details.
Use the Do you need to add local sizing? prompt to determine whether or not you are going to add local sizing objects to your part replacement task. Selecting Yes will create a new Add Local Sizing for Part Replacement task. This task is where you can define local size controls for your part replacement regions. See Adding Local Sizing for Replacement Parts for details.
Use the Do you need to add boundary layers? prompt to determine whether or not you are going to add additional boundary layers to your part replacement task, for newly appended objects. Selecting Yes will create a new Add Boundary Layers for Part Replacement task. This task is where you can define local boundary layer and prism controls for your part replacement regions. See Adding Boundary Layers for Replacement Parts for details.
Click Choose Part Replacement Options to apply your changes for this task before proceeding to the next task.
If you need to make adjustments to any of your settings in this task, click Revert and Edit, make your changes and click Update, or click Cancel to cancel your changes.
Once the task is added, there are additional subtasks that you need to complete, regardless of your selections in the Choose Part Replacement Options task:
Part Replacement Settings - a task where you can define specific details surrounding your overall part replacement options. See Applying Part Replacement Settings for details.
Update the Volume Mesh - a task where you can easily regenerate the volume mesh around the specific areas surrounding the replaced parts. See Updating the Volume Mesh for details.
This task is a similar to the workflow's initial CAD import and part management task, with many of the same settings, however, it is designed to just accommodate appending new, additional CAD parts that you will want to add to the workflow as replacement parts. For any new CAD files you want to use as part replacements, append them to the workflow's original geometry using this part replacement-specific task. See Importing CAD Geometries and Managing CAD Parts (and Appending CAD Files) for more information about the various settings in this task.
In addition using this task to import new CAD parts, you can also use this task to define special transformations to apply to your part replacements if necessary, such as rotations and translations. See Performing Operations on Meshing Model Objects for more information about object transformations.
Note: This task is not available if you have any objects that contain solids.
Use this task to define a particular part replacement strategy: whether you are adding, removing, or replacing a part; and identifying the part(s) you are using as a replacement and the part(s) you are going to replace.
Provide a Name, or use the default name.
Choose an Operation to perform for this part replacement task. You can choose from Replacement, Addition, or Removal.
Choose a particular Method of replacement. You can choose from Surface Mesh Based or Volume Mesh Based.
The volume mesh based approach defines a separate region for the area of interest surrounding the part replacement. Volume meshing is performed only in this region and thus is much faster than regenerating the entire volume mesh.
Note: To use the Volume Mesh Based approach, you must create construction surfaces to surround the area of the part to be replaced. See Identifying Construction Surfaces for more information. This method will be selected by default if Ansys Fluent detects any existing construction surfaces in the workflow.
While the surface mesh approach does not require construction surfaces, the approach does require you to remesh all of your volume regions, even though the surface mesh is updated only for the replacement part(s). This approach can be useful for smaller, more subtle part replacements while still maintaining performance.
For part replacement or removal, use the Select a Source Object list to pick the original object(s) that you wish to replace or remove. By default, you can use the Filter Text drop-down to provide text and/or regular expressions in filtering the list (for example, using *, ?, and []). See Filtering Lists and Using Wildcards in the Fluent User's Guide for more information.
For part replacement or addition, use the Select a Target Object list to pick the new object(s) that you wish to replace or add. By default, you can use the Filter Text drop-down to provide text and/or regular expressions in filtering the list (for example, using *, ?, and []). See Filtering Lists and Using Wildcards in the Fluent User's Guide for more information.
Note: Part replacement does not support regions with boundary layers defined on selected-zones or selected-labels; only boundary layers defined on all-zones or only-walls are supported.
Under Advanced Options, you have the following settings:
Specify a value for the Scaling Factor for New Objects option. This will determine the size of the bounding box surrounding the selected object where the part replacement is to take place.
For Define Location Using field, choose a method to specify the location of the region:
Select Numerical Inputs to assign specific coordinates to a particular region. You can use the View Exact Coordinates field to see and edit the specific X, Y, and Z coordinate values for the region's identified location.
Note: This technique generally uses the selected object's centroid to define the initial location point and may require further refinement. More accurate location refinement is achieved more specifically using the x, y, and z inputs and occasionally previewing the location.
Select Region Around Source Objects to calculate the position of the region based on the selected object(s).
Click Part Replacement to update the task with your selections.
If you need to make adjustments to any of your settings in this task, click Revert and Edit, make your changes and click Update, or click Cancel to cancel your changes.
Use this task to add local sizing to your part replacements. This task is similar to the existing Add Local Sizing task. See Adding Local Size Controls for more information.
When processing the Choose Part Replacement Options task, the workflow will notify you if there is no existing Add Local Sizing task, and if so, the workflow checks the settings in the Add Local Sizing for Part Replacement task and compares them to the existing Add Local Sizing task.
Use this task to add local boundary layer and prism settings to your part replacements. This task is similar to the existing Add Boundary Layers task. See Adding Boundary Layers for more information.
When working in the Add Boundary Layers for Part Replacement task, the workflow checks the settings in this task and compares them to the existing Add Boundary Layers task. For instance, any zones previously defined in the Add Boundary Layers task are compared to those specified in this task.
Note: If you have already defined your fluid region's boundary layer along all-walls or all-zones in the existing Add Boundary Layers task, then since the new part is associated with the same fluid region, the new part will also have the same boundary layer settings associated with it.
When you have completed your part replacement settings, you can proceed to updating the volume mesh.
Select Enable Parallel Meshing for Fluids if you would like to perform parallel volume meshing on your fluid region(s) for poly, hexcore and poly-hexcore volume fill types. When parallel is enabled, both boundary layer generation methods are parallelized: continuous and stair-step (also called "scoped").
Click the Generate the Volume Mesh button to update the volume mesh.
Note: When the volume is filled for part replacement, the mesh is distributed for parallel meshing, then agglomerated and migrated to a single active node. Therefore, parallel checks will only show one active node even when parallel meshing is used successfully.
If you need to make adjustments to any of your settings in this task, click Revert and Edit, make your changes and click Update, or click Cancel to cancel your changes.