How to consider location weather data in Butterfly?

Dear All,
Kindly help me. I am working on a CFD analysis for indoor space using Butterfly. How to consider location weather data in Butterfly?? is there any way to connect/analyze wind rose data for a specific location?

any help, please! :innocent:

Please, anyone, help me. I am searching regarding this issue for a while and find nothing!

hi @randa_medhat86

the data you get from the epw and that you read via a wind rose, corresponds to wind speed measured at 10m in height.

have you managed to run butterfly for indoor space?

Hi @OlivierDambron
Thanks a lot for your kind reply. Can you please explain more about connecting ladybug rose to Butterfly components? Sorry, I am a beginner.
No, I didn’t run the CFD analysis for the indoor space yet.

I am not sure what kind of analysis you want to do, but here is a simple sample file. (100.3 KB)

Thank you so much for your kind help. I appreciate your support. Regarding the ventilation sample: are you testing the natural ventilation inside the building or it’s an outdoor analysis?
I didn’t see where is the windows (openings) are set/connected in the file!
It’s very helpful to me that you are connecting whether file data.
I am testing the natural ventilation inside an open office, it’s located on the 1st floor in a 5 story building. I want to optimize the natural ventilation inside the office using outdoor windows as inlet boundaries and indoor doors as an outlet boundary (I may add more openings in the indoor wall to enhance the air quality).

Hi @randa_medhat86

I’m not sure BF is currently well equipped to do that. If you are going to use BF to do it, I don’t think you can do a yearly (or any lognitudinal) analysis given how long it takes to simulate all that.

What you can try is get reference velocities for the periods of interest and then simulate your building, with its context, in an outdoor study with probe points calculating pressure at the locations of your windows / doors. Then, in another simulation (indoor this time) you could use the calculated values as initial conditions. Again, this captures a point in time.

If your model is small, you could also simply do a directly outdoor study and simulate the space with windows open (typically in CFD studies, at least for building certification, we assume doors are closed but if you’re testing cross ventilation it could be alright to have it open).

Hope some of this helps. The best advice I can give you is to try, trial and error is a big part of this. Start with very simple models and move your way up.


In this sample, the windows are created with Rec 2Pt in the upper left corner. Outdoor and indoor are calculated at the same time.TheodorosGalanos gives good advice on how to calculate indoor and outdoor separately.

If you want to do an annual calculation, you can also consider using multizone air flow modelling software (e.g. CONTAM, COMIS, etc.), not CFD. However, this method does not provide the wind speed distribution in the room, and I do not know if it is possible to do this calculation on grasshopper.

Thank you so much for your precious ideas. I will start to try as you advised. I hope I can ask you if I faced any errors.
As a part of “kinonotofu” comment. May I ask if it’s possible to get the wind speed distribution in the room via Butterfly/Grasshopper?
Thanks again

Thanks a lot for your kind reply and clarification. I will start in my trial and error procedure and I hope I can get to you back if I faced some errors.
Thanks again

@kinonotofu @OlivierDambron @TheodorosGalanos
Dear all, May I ask your help again please, I have two questions:
1- How to determine the suitable end-time in both outdoor and indoor analysis (to get accurate results).
2- How can I set an optimization process to maximize wind speed (objecting to the suitable window to wall ratio). I want to know where I can connect the equation (also I want the insure the setting of the equation) to the U results? which component?

I will greatly appreciate it if there are any helpful materials.
Thanks a million

I think it’s better to start a new thread since the topic has changed.

1- The appropriate end time varies from case to case. It is important to know how to determine if the calculation has converged. In practical use, the convergence criteria is often set to be residuals below 1e-4.For research purposes, 1e-6 or smaller may be used. If the residuals do not go down, then you need to take measures such as reducing the relaxation factor. In addition to this, even if the total residuals go down, they may not go down locally. In the end, you need to judge for yourself. It is a very difficult problem to determine the general appropriate end time.

2- Galapagos, Octopus, and Wallacei are components for optimization. You may want to consider these. However, keep in mind that CFD takes a lot of time per calculation. If optimization methods other than these metaheuristics are desirable, you may want to ask questions in other communities. In this case, you may have to build your own algorithm.

@kinonotofu Thanks a lot for your kind clarification