Reno Genest
Ansys Employee

You can create the BCs in LSPP as described above, save the .k file with LSPP. Then, open the .k file with a text editor and copy/paste the *DEFINE_CURVE, *DEFINE_VECTOR, *DEFINE_COORDINATE_NODES, and *BOUNDARY_PRESCRIBED_MOTION_NODE into a command snippet in Mechanical. 

In the following example, I apply a velocity in the tangential direction on the top edge and I constrained the bottom edge in the tangential direction only. This uses the DOF=4 option on *BOUNDARY_PRESCRIBED_MOTION_NODE to use a vector to define the tangential direction:



Let me know if this helps or not.