Applying Pressure BC and Activating UDF Options for Kinematic Condition

[mamadreza9561]

 

Question:
I am simulating the physics shown in the attached image. The model includes a free surface where I want to apply a kinematic condition. I have two questions:

1. Is it possible to apply a pressure boundary condition directly on the free surface? If yes, how can this be done in ANSYS Polyflow?

2. As shown in the image, I want to apply a normal force kinematic condition on the free surface, and the force I need to apply follows a specific formulation (so I need a UDF). However, the three options highlighted in the red box (Multi-ramp function of Z coordinate, Map from CSV/Excel file, User-defined function) are currently inactive. How can I activate these options?

Any guidance or steps would be greatly appreciated.