Visualising Chemical Potential in Cahn Hilliard

Dear All,

I was following the Cahn-Hilliard fenics tutorial.

  1. I wanted to know how to visualize the chemical potential field since it contains a second order derivative and the tutorial only uses Lagrange elements which are H1 conforming.
  2. A secondary conceptual question I had is: Is it possible to visualize the Laplacian of any function constructed from Lagrange elements? Why is the weak form not well-defined for such an projection?

I have attached a screenshot of the chemical potential and the concentration field where I clearly see one is discontinuous while the other is continuous.
3)Finally in what ways can I visualize physical fluxes of the concentration field in such FEM codes?

@dokken could you help out with this? :slight_smile: