[Getfem-users] Multiple Dirichlet cond. bricks in a 2D Stokes flow problem

[Iago Barbeiro]

Dear Getfem users,

Iwould like to solve the 2D Stokes flow around a half cylinder with symmetry and Dirichlet inlet condition.

I started building my domain with a simple unit square structured mesh, in which  I applied  this  geometric transformation:

x'=(Rcy+y^n*(Rex-Rcy))*cos((1-x)*pi);
y'=(Rcy+y^n*(Rex-Rcy))*sin((1-x)*pi);

that gives the following result:

 ______                      __
 |          |                  /        \
 |          |     ->       /      _      \ 
 |_____ |              |___/    \___|
                                   |-|         Rcy
                                   |------- |   Rex

Using the test example "stokes.cc" I was able to solve this problem with this set of boundary conditions:

Body (half cylinder inside) : Homogeneous Dirichlet (no-slip)
Inlet  (half circular exterior boundary): Non Homogeneous Dirichlet (U=1i+0j)
Botton (two straight segments): Homogeneous Neumann 

This case has given me good results, but THEN