Free Slip boundary condition


Currently looking to implement free-slip for my Navier-Stokes solver, but I’m not sure how this would work. Thus far I’ve used VectorH1() with dirichlet and “do-nothing” boundary conditions, but I need to specifiy that one component has 0 velocity, while another is free to change. I suppose I could do something like V = H1*H1 with different boundary conditions, but is there some other/cleaner way to do it?



for the VectorH1 space you can use different boundary conditions for its Cartesian components via the dirichletx, dirichlety (and dirichletz for 3D) flags, e.g.

fes = VectorH1(mesh, order=1, dirichletx="left|right", dirichlety="top|bottom")


Works great, thanks!