The Choose Mesh Control Options task allows you to pick and choose various means of generating and refining the mesh in your simulation.
Specify how you would like to manage your size controls.
Select Create new to start with a new collection of size controls.
If you are creating new size controls, you need to specify the nature of the size controls you are going to use.
Select Default to create curvature and proximity size controls with default settings, as well as local size controls based on the number of objects in your model (such as external flow regions, or local refinement regions). Using this option and updating the task will add an Add Local Sizing task to the workflow and as many size controls as there are objects, each using their own default settings. You can also choose to create your own custom size controls using the Default option, and they will be retained until you remove them, even when the task has been reverted.
In the event that you remove any local sizing controls when using the Default option, you can quickly restore them by updating the Choose Mesh Control Options task. In addition, in the event that you make changes to the default values and/or remove any altered local sing controls, Fluent will provide information and guidance as to how to restore any missing sizing controls, if desired, when you update the task.
Select Custom to populate as many size controls as you need using your own customized settings. Using this option and updating the task will add a single Add Local Sizing task to your workflow, where you create as many size controls as you require.
Note: For either default or custom size controls, you can choose to use the Reset button's Re-Create Local Refinement Regions Sizing option (located at the bottom of the task). This option removes any existing local refinement settings and adds new local refinement settings based on the default size controls created in earlier tasks.
For more information, see (see Adding Local Size Controls)
Select Read existing size control file to add your size controls based on those already defined in a size control file (
*.szcontrol).Use the Compute Size Field For field to determine which type of existing size field file you are going to use. Choose from:
Both Wrap and Target - use this option if you already have the wrap and target size fields computed and saved in separate files. Supply the file name and location for both the Wrap Size Control File and the Target Size Control File fields.
Target Only (the default) - use this option if you only have the target size field computed and saved in a separate file. Supply the file name and location using the Target Size Control File field.
Select Wrap Only - use this option if you only have the wrap size field computed and saved in a separate file. Supply the file name and location using the Wrap Size Control File field.
If you have chosen Target Only or Wrap Only, you will need to specify a value for the Wrap/Target Size Field Ratio field, or keep the default value. This is the ratio of the wrap size and the target size controls. For example, if this ratio is 0.67 and the initial minimum target size is 1 and initial maximum target size is 16, then the initial minimum wrap size will be 0.67 and the initial maximum wrap size will be 10.72 .This value does not affect the BOI or soft size controls, such that the Wrap/Target Size Field Ratio is set to 1 for BOI or soft size controls. See Working With Wrap and Target Sizes for more information.
Select Read existing size field file in order to use a size field file (
*.sf) that is already computed.Use the Existing Size Field For field to determine which type of existing size field file you are going to use. You can select from:
Both Wrap and Target (the default) - use this option if you already have the wrap and target size fields computed and saved in separate files. Supply the file name and location for both the Wrap Size Field File and the Target Size Field File fields.
Target Only - use this option if you only have the target size field computed and saved in a separate file. Supply the file name and location using the Target Size Field File field.
Select Wrap Only, use this option if you only have the wrap size field computed and saved in a separate file. Supply the file name and location using the Wrap Size Field File field.
If you choose Target Only or Wrap Only, you will need to specify a value for the Wrap/Target Size Field Ratio field, or keep the default value. This is the ratio of the wrap size and the target size controls. For example, if this ratio is 0.67 and the initial minimum target size is 1 and initial maximum target size is 16, then the initial minimum wrap size will be 0.67 and the initial maximum wrap size will be 10.72 .This value does not affect the BOI or soft size controls, such that the Wrap/Target Size Field Ratio is set to 1 for BOI or soft size controls. See Working With Wrap and Target Sizes for more information.
Click Advanced Options to access additional controls prior to performing this task. Options include:
For the Apply Quick Edge Proximity? prompt, select Yes to speed up the calculation and reduce memory requirements when using a proximity size function with geometries having a very large number of small feature edges.
Specify a value for the Solid/Fluid Size Ratio field, or keep the default. This is the ratio of the actual size of the solid and the actual size of the fluid, used for solid meshing. For example, if this ratio is 1.5 and the fluid size is 1, then the solid size will be 1.5
Once your selections are made, click Choose Options and proceed onto 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.
Use the Restore Local Sizings button to return to your original local sizing objects and their default settings.
Fluent Meshing uses both target and wrap size fields. First, the geometry is wrapped using finer wrap sizes. Then, the wrapper nodes are snapped to the feature edges. Finally, the wrapper surfaces are re-meshed using the desired, coarser, target sizes. The wrapper size determines what features will be captured and what features will be ignored. Since the wrapper size produces surface meshes that are too fine (in order to capture features), the remeshing operation significantly reduces the size while respecting those features.
You can use the Compute Size Field For field to have more flexibility and control when calculating the size field for very complex models. By default, the size field is calculated for Both Wrap and Target. If you choose Target Only or Wrap Only, however, only one size field is calculated. The other size field is determined using the Wrap/Target Size Control Ratio, rather than being recalculated, potentially saving computational resources for very complicated models.
These settings will determine the size control settings in the subsequent Add Local Sizing task (Adding Local Size Controls), and how the size controls are calculated. If you select Both Wrap and Target, then you will have to set size control properties (minimum size, maximum size, growth rate, and curvature normal angle) for both the target and the wrap objects. However, if you select Target Only, you only need to provide values for the target's size control properties. Likewise, if you select Wrap Only, you must provide values for just the wrap's size control properties.
Note: As stated earlier, in order to properly capture wrapped regions and boundaries, the Fault-tolerant Meshing workflow uses two types of size controls:
Initial (Wrap) - a finer size control used for more refined mesh resolution to ensure geometry capture and region identification. This value is calculated using the wrap/target size ratio and the target size value.
Target - the coarser size control used in re-meshing to the required mesh resolution for the solution.
The wrap/target size ratio default value is 2/3 and is recommended in most cases, however, you may occasionally need to decrease this value to better capture geometric features.
Note: When using the Both Wrap and Target option, the surface or volume mesh generated will be the same quality as one that is read into the workflow. However, when using either the Target Only or the Wrap Only options, you will have two different meshes because the target size fields of these two options are different.
With the Target Only option, the size defined in the Add Local Sizing task are going to be used in both surface and volume meshing and will directly decide the target size field, Also, the Wrap/Target Size Field Ratio is going to affect the feature extraction such that a smaller value will increase computational costs but yield a more accurate result.
With the Wrap Only option, however, the target size field is based on the Wrap/Target Size Field Ratio, where everything is scaled by the inverse of the ratio. The wrap sizes defined in the Add Local Sizing task are used to help you control how exactly you want to capture the original geometry, however, the Wrap/Target Size Field Ratio will be used to calculate the target size field which is equal to the inverse of the product of the Wrap/Target Size Field Ratio and the wrap size field (including the boi and soft sizing types). It should also be noted that you can use size boxes (available using the Show Size Box or the Show Wrap Size Box check boxes in the Add Local Sizing task) to preview the size boxes if necessary. When using the Wrap Only option, you should use the Show Size Box check box because it will have a coarser mesh when compared to the defined wrap sizes.