The mesh
To do the calculations, we have chosen a regular structured mesh. As we can see on the drawing below, the cells have got four faces. The numbers of cells is 10 * 180.
The radius of the inner circle is 0.5 m and the radius of the outer circle is 1m.
 

Moreover, StarCD needs a 3D-mesh to calculate, even for a 2D problem. So, the previous 2D-mesh has been extruded to be used with StarCD. There is only one cell in the extruded direction. Even if the dimensions of this cell appears important towards the other dimensions, it has no effect on the calculus. It means that we are simulating a two-dimensional flow.
It must be noticed that the mesh used is not the one made from StarCD, but an imported mesh from Gambit.