How to obtain the same volume of mesh

Dome

Dear all Guru

I am new for ANSYS CFX 5.7 and would like to use the CFX5.7 to solve the problem of hot air stream flows over the cooled surface with the wind shield. The temperature difference between the cooled surface and air stream is 5 C (air 25C, cooled surface 20C).

The aim of this investigation is to reduce the convective heat transfer coefficient by placing obstacles in the rectangular shape which is protruding form planar surface (rectangular wind shield on the planar surface).

The 3D fluid domain was selected for this problem. In this case, the rectangular box opened at the top is protruding from the bottom surface of 3D long rectangular fluid domain.

The ANSYS Workbench 8.1 is employed for meshing and send the .gmt file to CFX for investigation the effect of increasing the depth of the rectangular box on the value of convective heat transfer coefficient at this bottom surface . I suspected some of the problems:

How to control the number of surface mesh with different geometry, because when I increasing the depth of rectangular box the geometry configuration of fluid domain (the volume of fluid regime) was changed due to the increasing in depth.

So, according to this problem, I am unable to compare the results heat transfer coefficient at the bottom surface of the rectangular box from each different geometry configurations.

Note, to compare the results heat transfer coefficient of this case, all of input parameters for CFX solve are the same. Thus, how to obtain the equality among of the volume mesh, even of small different geometries in each case but within the same dimension of cover fluid regime.

Please, give me some comments and suggestions to solve this problem.

Regards,

Dome.