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Applying the Growth Distribution Function to Connectors (2D T-Rex)

After 2D T-Rex grids are created, you may find that the distribution of grid points on connectors that touch the edge from which anisotropic triangles grow may not match the growth of anisotropic layers. These distributions can be set to match your T-Rex grid easily by applying the Growth distribution function to the connectors.

Begin with a 2D T-Rex grid like the example shown below of a wing where the curvature of the leading edge was resolved by anisotropic triangles. Notice that the Chordwise Connectors near the leading edge do not have the same initial spacing or growth rate as the T-Rex grids.

A wing with an unstructured T-Rex mesh

Refer to the example and apply the steps to your own geometry. Note that the numbers in the following steps apply to the example; you will need to determine which settings work best for your own grid.

  1. Click the All Masks On/Off button to mask all entity types.
  2. Check the Connectors mask.
  3. Select the three Chordwise Connectors.
  4. Grid, Distribute
  5. Select the three Chordwise spacing constraints near the leading edge of the wing, as shown below.
  6. The three Chordwise spacing constraints near the leading edge of the wing
  7. Enter 0.2 for Spacing.
  8. This value must be the same initial spacing that was used for the Δs field of the Wall BC when creating the T-Rex grids.

  9. Apply
  10. Select the three Chordwise spacing constraints near the trailing edge of the wing, as shown below.
  11. The three Chordwise spacing constraints near the trailing edge of the wing
  12. Enter 2.0 for Spacing.
  13. This value should be approximately the same spacing as the spanwise spacing constraints at the trailing edge root.

  14. Apply
After spacing constraints are applied to the Chordwise Connectors

The image above shows the grid after all spacing constraints have been set. Notice that the spacing still does not match that of the T-Rex grid, as you can see clearly on the tip of the wing. Now we need to apply appropriate growth distribution parameters to the connectors.

  1. Click on the Distribute, Functions tab.
  2. Toggle on Growth in the Function frame.
  3. Notice the symbols that appear on the ends of the selected connectors in the image below. A triangle symbol indicates the beginning of the connector distribution and a square symbol indicates the end. You can see in this example, the beginning of the connector distributions are at the leading edge and the ends are at the trailing edge.

    Triangle and square symbols indicate the beginning and ending of the connector distribution
  4. Make sure the Growth Distribution Parameters frame is checked.
  5. Make sure the Number of Layers and Growth Rate is selected as the option for Begin.
  6. We will set the same values here that we applied when creating the T-Rex grids.

  7. Enter 10 for Number of Layers.
  8. Enter 1.3 for Growth Rate.
  9. Apply

Notice that we left the End Growth Distribution Parameters set to zero. This is because no growth occurs on the end of the Chordwise Connectors' distribution.

If you are satisfied with the updated connector distribution and grid, click OK. But if you think the Chordwise Connectors now need more or less grid points past the T-Rex region of the domains, you can fix this in the Dimension tab.

You can see in the image below that for our example, the spacing towards the trailing edge of the connector on the tip of the wing still needs more grid points.

After the growth ditribution function is applied to the beginning of the Chordwise Connectors
  1. Click on the Distribute, Dimension tab.
  2. Select the first Chordwise Connector.
  3. Set Optimal Dimension
  4. Select Connector
  5. Select the second Chordwise Connector.
  6. Set Optimal Dimension
  7. Select Connector
  8. Select the third Chordwise Connector.
  9. Set Optimal Dimension
  10. Select Connector
  11. Apply
  12. OK

The Set Optimal Dimension command calculates and applies grid points so that you have a smooth distribution between the T-Rex region of the connector distribution and the end spacing.

Now you can see how our new growth distribution function can help you match connectors to 2D T-Rex grids quickly and easily.

An example of a T-Rex mesh after connector distribtuion has been adjusted The T-Rex mesh around the connection of two domains

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If you have questions about the steps outlined above or on any other meshing topic, please contact us via one of the following methods.

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