mesh of large aspect ratio region

marangoni

Hi:

In gambit, I try to mesh a face(rectangle): the length is about several meters, but the width only about 200 micron. After I mesh the face(the aspect ratio is about 1:10000), what I find out is for the region some distance from either end of long side, the mesh is not the same as that at either end. When I read grid into fluent, the minimum and maximum volume shown are not the same (the difference is quite large), some time even fails the grid check (negative area and volume). Anyone has some suggestion about this?

Thanks

M