''Contact sizing'' in 2D Fluent meshing
 

Hello everone,
I am new to Ansys Fluent and I am facing a ''contact sizing'' problem between a fluid zone and a solid part. In order to analyse accurate heat transfer between a fluid region and the solid part, the interface boundary has to be properly meshed. Attached is the picture showing an improper contact sizing at the interface.
I have also tried contact sizing feature in meshing but I haven't got what I expected.

Please help me with this....