Stochastic Stokes periodic boundary conditions in freefem crash on launch

General Discussion
1

Hello everyone,
I am reproducing the temporal convergence rate experiment from this paper. I have removed the Dirichlet boundary conditions and added periodic boundary conditions. The program exits automatically after about 4 seconds of runtime, with no error messages and no log files generated. Could anyone tell me what might cause this problem?
StochasticStokes.pdf (1.7 MB)
stokes.edp (7.4 KB)
normal_K2_N600_M16.zip (161.3 KB)

2

Hello,
Since you define the space Xh with four unknowns and declare
Xh [u1,u2,xi,r],[v1,v2,Phi,q];
you cannot define the problems
problem B(xi,Phi)
and
problem St([u1,u2,r],[v1,v2,q])
that have only 1 or 3 unknowns. For solving these you need to define spaces XB and Xstokes with 1 and 3 unknowns respectively, and define the associated unknowns and problems

XB xxi,PPhi;
problem B(xxi,PPhi)

Xstokes [uu1,uu2,rr],[vv1,vv2,qq];
problem St([uu1,uu2,rr],[vv1,vv2,qq])

Next you can gather the results in the unknown [u1,u2,xi,r] as
[u1,u2,xi,r]=[uu1,uu2,xxi,rr];
Here is your modified code
stokes-sylvia.edp (7.9 KB)