Hi

i have a question please.

We consider the following equation:

L*(du/dt - \Delta u + c(x,y) . \nabla u + w q_{\delta}(x/\eps,y/eps) u) = L*f(x,t), x \in [0,1], t \in [0,1],

where L is real fixed and esp is positif fixed.

with initial condition: u(x,0)=0 and with periodic boundary conditions, and c(x,y)=(y,-x).

I try to write the variational formulation associated to this problem. Please is it correct to write

mesh Th=square(N,N,[x,y]);

fespace Vh(Th,P1,periodic=[[2,y],[4,y],[1,x],[3,x]]);

fespace Wh(Th,P2,periodic=[[2,y],[4,y],[1,x],[3,x]]);

Vh uh=0.0;

Vh wh=0.0;

Vh vh;

Vh fh;

Vh oldU=0.0;

Vh oldW=0.0;

problem het(uh,vh,init=t) =

```
int2d(Th)(L*(dx(uh)*dx(vh)+dy(uh)*dy(vh))*dt)
+int2d(Th)(L*(y*dx(uh)*vh - x*dy(uh)*vh))
+int2d(Th)(L*uh*vh)
-int2d(Th)(L*oldU*vh)
+int2d(Th)(qdelta(x/eps,y/eps,w)*uh*vh*dt)
-int2d(Th)(fh*vh*dt)
;
```

Thank you in advance to the help.

Regards