🚀 go-pugleaf

Hi, 
I am solving Navier-Stokes Eqn. using FEM (Penalty-function method) right 
now. I have read lots of papers, but nobody mentioned how they handeled
the force vector. The force vector is

	F1=line or suface integration of(tx)
	F2=line or suface integration of(ty)
where
	tx= 2.0*mu*(du/dx)*nx+mu*((du/dy)+(dv/dx))*ny-p*nx
	ty= mu*((du/dy)+(dv/dx))*nx+2.0*mu*(du/dx)*nx-p*nx
and
   	p=-(penalty number)*(du/dx+dv/dy)

I am now using iteration method to handel this, ie first I assume a velocity
profile, secondly calculate the force vector and then sove for the velocity.
After this , I use the vel. got for the next iteration. But it seems that 
the result does not converge.

Is there anyone can give me some help? 

Regards.

lixin

email: lzhao@uoft02.utoledo.edu