[cfdsolver1]

Hello everyone. I am beginner level OpenFOAM user. I am trying to simulate my 3D problem in 2D domain to get used to the environment and solvers of OpenFOAM. I tried to draw my problem in this file: http://imgur.com/iEHWKoU

I need to import STL file in my real problem; so imported solid.STL file and mesh it by using blockMesh and snappyHexMesh. I have inlet, outlet, slip and fixedWall boundaries in my problem. I solved this problem using buoyantBoussinesqSimpleFoam and obtained U and T values at each point. Now, what I want to do is calculating wall heat flux at fluid-solid interface.

I have an experience in Fluent; so in Fluent, I need to have an interface boundary between fluid and solid to evaluate wall heat flux. How this can be done in OpenFOAM? Do I need to have an interface to calculate wall heat flux in OpenFOAM or it handles this automatically, somewhow? Do I need another solver to obtain wall heat flux or can I obtain it by using buoyantBoussinesqSimpleFoam solver?

I have checked several tutorials online and I am very confused so any help is appreciated.