Problem of Meshing a orifice within a very thin pipe
 

Hi there,

I'm simulating the flow in orifice meter. The diameter of the pipe is 12.5mm, and the orifice diameter is 4mm. The following figure shows the geometry of the orifice.

https://lh3.googleusercontent.com/-5...c/s800/123.png

When I doing the mesh, I separated the body into serval small rectangular parts. However, one of the rectangular is very small. How do I mesh that one?