Error when trying to use LES turbulence model


Hello. I am a bit new to butterfly so I apologise if this is a simple issue. I am using the outdoor example file and am trying to run the simulation using the LES turbulence model. However, I get the following error:

I’ve tried different turbulence models like the default kEqn and WALE in addition to Smagorinsky and still same error. RAS turbulence models work fine.


Did you check line 24 in LES file? That should help you to identify the source of the error.


Thanks for the quick reply. I opened the file in the directory mentioned but this is all it says.



I don’t think LES is properly implemented in Butterfly yet. Only the most used RAS models have been properly implemented.

Kind regards,


Oh I see. Do you know if there are any plans to introduce them soon? Or maybe if it is simple enough a way that I could implement it? For part of my thesis I was hoping to compare a few RAS and LES models before deciding which to use.


That would be pretty nice if you could!

The easiest way would be to maybe send us a default / best-practice LES case for outdoor and/or indoor cases. That should be enough to get us going.

Of course, if you want to contribute that directly in code I’m sure @mostapha wouldn’t mind :slight_smile:


OK great. Not totally sure what you mean though. Perhaps, some papers or case studies using LES? I’m very early in my thesis so my experience in butterfly, and in CFD as a whole, is a bit limited but I’m exploring it extensively. I have read a lot of literature involving LES for engineering purposes. I hope to use it for wind load analysis on high-rise buildings with complex geometry. I also have some python experience but i’m sure you guys are leagues ahead of me in that regard :grinning:. Let me know, if anything, what I can contribute, either here or you can contact me privately as well. Thanks.


@errone92 It would be great if by the end of your thesis you had a set of best practices of how to set up LES cases for typical use cases (e.g. for the built environment). Those would definitely be a great addition to Butterfly.

Good luck in your research!

Kind regards,