Hello. I am trying to apply the following boundary condition in FEniCS:
$\mathbf{u} (x,y=b,t)\cdot \mathbf{n} =$ constant in space on $ \Gamma_t \times I$
This states that the displacements on the top boundary must all be the same. Note that the domain is a 2D rectangle where b is the height of the domain and t is the time at the current time step. Is there a built-in way to apply this?
