Example

Example

This example uses a model of an airfoil to demonstrate setting up a periodic mesh. In this example there is an airfoil wall surface and two walls on either side of the airfoil. A translational periodic parameter is used in the mesh generator. Below is an image of the model, where the blue (named Side1) and red (named Side2) are the surfaces which a periodic mesh will be applied.

Figure 2.

The image below shows the model set up in the Data Tree. Notice currently that there is no periodic surface defined.

Figure 3.

The distance between the periodic surfaces must be known. If it not known, it can be found by selecting the surface in the Model Tree and right-clicking on the surface name. When this is done a menu will appear. Selecting Info will provide maximum x, y and z coordinates of the surface.

Repeat for both surfaces to determine the translational distance between the two. Once this is known the periodic parameter is ready to be defined.

Right-click on Periodics in the Data Tree and select New.

Once the new periodic has been created it will need to be defined. Right-click on the new periodic set and select Define.

This will open a dialog where the periodic set can be defined. The defining of Side 1 and Side 2 must agree with the translational off-set value, or rotational angle entered.

To select the surface to be used in the periodic set, select the eye ball or chose it from the drop down menu. If the eye ball is selected it will bring up a panel, shown below. From here the surface can be selected.

Here the surface named Side1 and Side2 are selected for Side 1 and Side 2 of the periodic set. Once these are identified, the type is selected by clicking on the drop down box next to Type.

After the type has been identified, the off-set is entered. In this model the surfaces are Side1 and Side2 and they are offset by 0.4572 meters. This means the surface named Side2 is 0.4572 meters in the positive z direction from the surface Side1.

The default tolerance is set to 0.001 meters. This is the tolerance used when generating matching nodes for the two periodic surfaces. This tolerance should be adjusted when the mesh size on the surface falls under the tolerance values. Once the periodic set is specified the mesh can be created. The image below shows the resulting mesh.

Figure 4.

The periodic matching can be examined by right-clicking on the periodic set in the Model Tree and selecting Display. A point, line or line and point can be selected to render the node matching.

Below is an example of the node matching using a line display.

Figure 5.

Below is an image zoomed in on the airfoil.

Figure 6.