[ninjakid]

I have problems with convection calculation on Fluent 13.0
I have a geometry (basically cylinder) with its surface heated to certain temperature and there is a boxed encloseure around the cylinder.
Cold air goes in from inlet duct at the front of the encloseure and goes around the cylinder to cool the surface and goes out from outlet vent at the back of the enclosure.
I am trying to calculate the convection around the surface of the cylinder.

The calculated convection within CFD model was lower than I expected.
This is because the surface area is lower than the actual model (it is more complicated and has more surface area) due to simplified geometry. f

Thus, I would like to make CFD calculated convection between the cylinder's surface and airflow around the cylinder to be doubled within Fluent somehow (maybe using a UDF??) instead of making detailed geometry. Let's say heat flux or heat transfer coefficient from wall to fluid (air) needs to be doubled:

q = q_convection + q_radiation
q_convection = h_f(T_w-T_f)

q_convection or h_f needs to be doubled to make the convection calculation doubled

Is there any way to do that?
I thought using DEFINE_HEAT_FLUX UDF may work, but I could not figure out.

Please let me know if anyone know how to do this.

Thank you.