CFD convection simulation for building with open sides

[mjs0757]

Hi,

I am an absolute novice at CFD, but I have set myself a task for an engineering project to determine the convection within a building with open sides. I have set radiation on and set the location for the sun and an initial midday time for summer solstice 21/12/25 (southern hemisphere). I wondering how I set the exterior walls as open to the environment. Effectively the building is a hybrid agricultural structure with the lower level an animal shelter as a composting barn, topped with a greenhouse for hydroponics. I just want to establish a baseline of the effects on the building before adding complicating factors such as compost generating heat , 660 cows.

I have also been looking at this in Ansys Fluent, which has a setting of ambient for the external surfaces but Autodesk CFD doesn't, what should I do for these walls. I used Autodesk CFD some 10 years ago just playing with heat in room generated by a log burner, so have a little more familiarity with its interface than I do with Fluent.

I did get one solve which didn't make sense temperature wise, generated a report (attached), CFD file also attached and snip of temp ortho image.

any help gratefully recieved

Malcolm (ps didn't like my cfz file so not attached)