I have a 3D geometry on which I would like to impose Periodic boundary conditions in 2 directions.
I unsuccessfully tried
pbc1 = PeriodicBoundary1()
pbc2 = PeriodicBoundary2()
V = FunctionSpace(mesh, "lagrange", 1, constrained_domain=[pbc1, pbc2])
Also I considered defining both conditions in one class, but did not come up with a working solution.
Can anyone tell me how to impose two periodic boundary conditions?
Many thanks