On 10/12/15 16:53, Floriane Gidel [RPG] wrote:
Dear all,
First of all, thanks a lot for your time last Friday, and your help both for the implementation and for the installation of Firedrake.
I am now trying to implement the equations we discussed on Friday, for the 3D potential flow equations. As a reminder, I solve the equations for phi, h, but also phi_s which is a 3D function, but is only updated at the free surface. However, I would like to update the interior nodes of phi_s as well, by copying the value of its surface nodes, as soon as they are updated (that is, simultaneously with solving the coupled equations). Is there a way to do this?
I attach a short pdf summarising the equations, the current implementation and the issue I get.
Thank you very much,
Floriane
I'm a little confused by your equations: phi_s only occurs in the top surface integral in R_phi_s, so why do you need it in 3D? Also R_phi_s only has one surface integral, so you cannot use a 3D test function q there, since you would get spurious equations for all q that are zero at the top. Finally you say you have a boundary condition that implies phi_s=phi^* at the top, but you don't indicate the time-level for phi^* in (1) - also you have to indicate what time level R_phi_star is at if you want to solve it in conjuction with R_phi_s. Is what you want to do solve for \phi^* using R_phi_star (which is independent of phi_s?) and then solve for phi_s via R_phi_s? Cheers Stephan