Hello,
I tried adapting the example NSE.edp in the FreeFem documentation to be fully periodic on the square. I get the error
Problem build of FEspace (2d) (may be : due to periodic Boundary condition missing ) FH
The number of DF must be 3600 and it is 3803
I am hoping someone can point me to an example. The critical part of my code is below.
Thanks,
Mike
fespace Xh(Th, P2, periodic=[[2, y], [4, y], [1, x], [3, x]]); //velocity component space
fespace Mh(Th, P1, periodic=[[2, y], [4, y], [1, x], [3, x]]); //pressure space
real dt = 0.01, nu=.1;
real alpha=20/dt;
Xh u2, v2, up1, up2;
Xh u1, v1, f1, f2;
Mh p, q;
problem NS (u1, u2, p, v1, v2, q, solver=Crout, init=i)
= int2d(Th)(
alpha*(u1v1 + u2v2)
+ nu * (
dx(u1)dx(v1) + dy(u1)dy(v1)
+ dx(u2)dx(v2) + dy(u2)dy(v2)
)
- pq(0.000001)
- pdx(v1) - pdy(v2)
- dx(u1)q - dy(u2)q
)
+ int2d(Th)(
- (f1v1+f2v2)
)
+ int2d(Th)(
- alpha*convect([up1,up2],-dt,up1)v1
- alphaconvect([up1,up2],-dt,up2)*v2
)
;