Definitions
Next, under the Component 1  > Definitions  node, some named selections will be added. These will be used during results processing.
Outer Surfaces
1
In the Definitions toolbar, click  Explicit.
2
In the Settings window for Explicit, type Outer Surfaces in the Label text field.
3
Locate the Input Entities section. From the Geometric entity level list, choose Boundary.
4
Select boundaries 1, 8, 19-23, 48-50, 57, and 58. These are the boundary numbers for the outer walls of tube.
An easier way to apply this selection is to first select the Group by continuous tangent checkbox. Then, in the Graphics window, click anywhere on the outer surface of the cylinder. This will cause that boundary and all boundaries tangent to it to be selected. Then, you only need to click the two ends of the cylinder to add them to the selection.
Blade Surfaces
1
In the Definitions toolbar, click  Explicit.
2
In the Settings window for Explicit, type Blade Surfaces in the Label text field.
3
Locate the Input Entities section. From the Geometric entity level list, choose Boundary.
4
Select boundaries 2-7, 9-18, 24-47, and 51-56, the mixing blade surfaces.
A shortcut for this selection is to first click Go to XY View  in the Graphics toolbar, then click Select Box . Click and drag in the Graphics window until the box contains all three blades, then release the mouse pointer. You might need to deselect just one or two outer pipe segments, like boundary 21.