Define Slip Walls
Use the Slip tool to define wall surfaces which have zero shear stress and through which there is no normal velocity.
- 
                Select the surfaces or thin solids on which
                    to apply the boundary condition.
                To Select Do This Surfaces Select surfaces in the following ways: - While in the Flow ribbon, select surfaces, then right-click and select from the context menu.
- From the Flow ribbon, click the
                                            Slip
                                        tool. 
 Figure 1.Select surfaces. 
 Thin Solids - From the Flow ribbon, click the
                                            Slip
                                        tool. 
 Figure 2.
- Change the guide bar selector to Thin Solids.
- Select thin solids.Note: You can only select thin solids if layers have been defined using the Thin tool.
- Select a direction option from the
                                guide bar.- Direction: Away from Parent Surface - Define the condition on the boundary surface furthest from the parent surface.
- Direction: Adjacent to Parent Surface - Define the condition on the boundary surface closest to the parent surface.
- Direction: Both Sides - Define the condition on both sides of the boundary surface.
 
 
- In the dialog, enter a value for Precedence.
- 
                From the guide bar, execute the command in the following
                    ways:
                - Click  to confirm your selection and remain in the
                            tool. to confirm your selection and remain in the
                            tool.This allows you to continue creating instances and helps you visualize and edit instances with the legend. 
- Click  to confirm your selection and exit the
                        tool. to confirm your selection and exit the
                        tool.
 
- Click