Pre-processing

Figure 7 Geometry to be created

The definition of the geometry is the first step to solve any problem. To create the box that encapsulates the flow, we only have to create the respective points, lines and surfaces using the Pre-processor tools. In the following paragraph we will show the necessary steps to create the geometry.

First the points with the co-ordinates listed below have to be entered using one of the many methods provided:

Point Nš:

X Coordinate

Y Coordinate

1

0.000000

0.000000

2

1.000000

0.000000

3

1.000000

1.000000

4

0.000000

1.000000

Then the lines have to be created from the corresponding points, using the Create Line (use Join or Ctrl+A) option (see Figure 8):

Figure 8 The Create Line option

Once all the lines are defined, the surface (control domain) has to be created (see Figure 9):

Figure 9 Nurbs Surface creation menu

It is important to note that the surface normals must be oriented in the OZ positive sense. This may be checked using the Draw Normals>Surfaces option of the Utilities menu.

If you need to change an orientation of a normal, select the above menu sequence (Utilities>Draw Normals>Surfaces), select the surface and right click the normal you want to change. From the Contextual menu select Contextual>Swap some then select the normal you want to swap (change the orientation).