## 35.4. Boundary Definition

CFX-Pre will automatically create boundary conditions based on name matching criteria, but you can define your own as follows:

1. Right-click in the blank area and select New to create a new boundary condition.

   A dialog box will pop up and ask for the name of the boundary condition you want to create.

2. Accept the default name or enter a new name.

3. Click OK.

4. Set Boundary Type to one of: `Inlet`, `Outlet`, `Symmetry`, or `Wall`.

   Opening type boundary conditions are not available using Quick Setup mode.

5. Set the location (2D Region) for the boundary condition.

   You may use the Ctrl key to multi-select a group of 2D regions for the single boundary condition.

6. Fill in information specific to the type of boundary condition.

   Additional information for a particular setting is available. For details, see Boundary Details Tab.

7. Repeat the preceding steps for each remaining boundary condition you want to create.

   You may delete any boundary conditions that are not required for the simulation simply by right-clicking the boundary condition in the list and selecting Delete from the shortcut menu.

   A default boundary condition will be created automatically for any 2D regions on the boundary of the domain, which have not been assigned a boundary condition. By default, the default boundary condition is a no-slip adiabatic wall.

8. Click Next to continue.

Release 18.2 - © ANSYS, Inc. All rights reserved.