Surface roughness?
 

If I have an object like this:

http://imageshack.us/a/img440/2637/inductor.jpg

It's a model of an inductor, the coils are 18 gage wire. My question is do I need to apply a roughness to this surface, or will STAR recognize the "bumps" along the geometry? I had someone tell me that STAR will consider these surfaces smooth as part of wall treatment but applying a roughness seems unnecessary if the wires are modeled individually as they are. Now, if each coil pack was just a solid cylindrical shape then I could see why a roughness would be needed but I'm not sure.

I think it depends on the fineness of the mesh close to the wires.