Change boundaries while iteration

I want to change boundaries while iteration.

related code I failed here:

real u0=0.0;
problem heat(u,v)
= int2d(Th)(KK*(dx(u)*dx(v)+dy(u)dy(v)))
+ on(inlet,u=u0);

for(int i=0;i<100;i++)
{ heat;

real cel=0.01i;
border SQ1(t=0, 1){x=8.0-cel
t; y=0.0; label=100;}
border SQ2(t=0, 1){x=8.0-cel-(1.0*t); y=0.0; label=inlet;}
border SQ3(t=0, 1){x=8.0-cel-1.0-(8.0-cel-1.0)*t; y=0.0; label=100;}

I thought border SQ2(inlet) will move to left while ‘cel’ is increasing.
but seems like it’s not, because when I claim ‘problem’, boundaries will be fixed with it.
Am I doing something wrong? Or Is there any other tricky way to do this?

  • I tried to create new mesh(which changed boundary) as Th, but it didn’t work.