Review and improve CFD model in ANSYS FLUENT

I’m working om a project for a building faculty, where we try to simulate ventilation of cold attic rooms. Cold attic rooms are attic rooms where insulation is placed on the interior surfaces and therefore they have a temperature close to outdoor temperature. The project is both based on full scale experiments combined with modellings and simulations in ANSYS FLUENT. The purpose of this model is to gain insight in how outdoor temperature and wind conditions influence ventilation of the attic room, and thereby also moisture conditions. We have run the setup with different settings for boundary conditions, but we’re in doubt about model since we encounter some results that we do not expect. Therefore, we suspect that there might be a problem with meshing, models, boundary conditions and/or solution method. We need someone who is well experienced in ANSYS FLUENT in CFD in general to validate the model and, if possible, make improvement to increase accuracy, shorten calculation time, and improve calculations ability to converge.