Hi Onno, I'm afraid I don't think we understand what you are asking for. Can you show us the maths please? Regards, David On Thu, 23 Feb 2017 at 08:07 Onno Bokhove <O.Bokhove@leeds.ac.uk> wrote:
Dear Firedrake(rs),
I am considering a "standard" FEM problem with the following variables h(chi,tau) and phi(chi,tau) as function of transformed coordinate chi and time tau in chi=[0,L].
In the weak formulation, the point value h(Lp,tau), so the function value at 0<chi=Lp<L
as well as, of course, the function h(chi,tau) appear in the space integral of the weak form.
In essence, due to a transformed moving boundary this point evaluation arises.
I can formulate the detailed (nonlinear) matrix-vector FEM and its time discretisation
because after the expansion of h(chi,tau) the coefficients h_j(tau) appear
and h(Lp,tau) = h_Np(tau) for j =Np, say, such that the distinction between function
and point values disappears.
I am struggling to see how I can do this on the weak form level in firedrake.
It would work in integral form by using a delta function after introducing h(Lp,tau)
as an auxiliary scalar variable but I assume that is not available?
What is the FD-tactic here which one can employ?
Thank you and best wishes,
Onno
-- Dr David Ham Department of Mathematics Imperial College London