Learning Forum

[Larz_Johnston]

Hi,

I'm trying to model the temperature profile of a greenhouse, heated by the sun and ventilated by natural wind flow, and I'm coming across one major issue in the theory. Because I'm modelling this greenhouse over the course of a month, the heating of the sun is naturally very different over the course of the experiment, so a standard heat flux value on the roof is not viable. I have an excel sheet with the heat flux I need at each time interval, so how do I link that list of values into the heat flux of the roof surface?

[Rob]

You can use a transient profile, that's a text file and is covered in the User's Guide. However, I'd also be looking at how you're going to do this. The CFD solver needs to resolve the flow time scales (typically fractions of a second) so the computational expense is going to be massive. As a starting point work out the incident energy and run (for example) a steady model for each hour from an hour before dawn until an hour after dusk. That'll give you some data on the flow field, and whether the change in solar load has much effect on the temperatures etc.