Description

The Boundary Conditions tab allows you to specify how each bounding domain of a block will be treated when using the T-Rex anisotropic meshing tool. The list operates nearly identically to the Set Boundary Conditions command for CAE use. It displays information on all the boundary conditions that have been set (including for domains) regardless of your current block selection.

This is the basic workflow:

  1. Use the New command to create a new T-Rex boundary condition.
  2. Select the domains to be assigned to the new T-Rex boundary condition.
  3. Check the appropriate Set checkbox to effectively assign the selected domains to the T-Rex boundary condition.
T-Rex BCs
Use the Boundary Conditions tab to specify how each edge of a domain will be treated for T-Rex meshing.

When baffles exist in the block, these domains will be listed in a second table at the bottom of the Boundary Conditions tab. This table provides easy list style selection of the baffle instances. In other words, both sides of the baffle domains appear in this list table.

TRex BC Selection
Boundaries are selected in the List or Display window.

When setting T-Rex boundary conditions, the currently selected bounding domains are highlighted in white. Note that when there is either a connection between two blocks or a baffle domain, arrows normal to the boundary are rendered to indicate which side of the connection or the baffle you are currently selecting (see figure above).

There are four types of boundary conditions available for the T-Rex algorithm:

  • Wall: Sets bounding domains to have anisotropic cells grown off of them. The accompanying Δ defines the initial height of those anisotropic cells.
  • Match: Sets bounding domains to have a grid point distribution that matches the growth of the interior anisotropic cells. Note that for the domains to be modified, you need to have the Push Attributes option checked on
  • Adjacent Grid: Sets bounding domains to have anisotropic cells grown off of them while matching the initial cell height to an adjacent block.
  • Off: Sets bounding domains to not have anisotropic cells grown off of them. Note that these domains will have isotropic cells applied along with the remaining block interior outside of the anisotropic layer.
 

Tip: When applying T-Rex boundary conditions, you can always leave domains as Unspecified when you want to use type Off since Unspecified defaults to the Off boundary condition type.

In the boundary condition table after the Δ column is the Adapt column. By default this option for each boundary condition will be set to Off. For the Unspecified boundary condition it cannot be changed from the default setting. As with other fields in the table, double click to change the value. Here you can select from On or Off. When set to On, domains assigned to the corresponding boundary condition will have their point clustering adapted, points added or removed, in order to meet the target cell sizes specified by any selected Size Field influencers. There must be size field domains or sources selected for use via the Size Field tab.

 

Note: The Adapt option can be applied to a T-Rex Wall type boundary condition. The wall domains will be adapted prior to marching T-Rex layers. This is the only way that size field entities can influence T-Rex layers. Once the initial front is set, size field entities have no effect on the interior volume cells of the T-Rex layers.

Finally, the last two columns of the boundary condition table provide summaries of how many individual triangle (Tri Count) and quadrilateral (Quad Count) cells are included in all of the domains assigned to each boundary condition. You can right-click any of the table headers to toggle these last two columns on and off.

Demonstration