Water Body in Outdoor CFD

Hello all,

What if the buildings we are using for outdoor CFD studies are surrounded by a water body? Is there a way to account for that in the CFD study? Any thoughts on this will be very appreciated.

i attached an image to convey the scenario. I am aware of the roughness coefficient that I can apply in Butterfly. My quesston is, what to do when you have low rise urban and water body both inside your wind tunnel?

Thank you!

Hi @devang,
Can’t say about Butterfly, but in ENVImet you can define water bodies.

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Thnaks @AbrahamYezioro for pinting out.
@TheodorosGalanos, can you please share your views?

hi @devang,

With the buoyantBoussinesqSimpleFoam solver implemented currently in the heattransfer recipe, you could model the water bodies as surfaces and set the temperature of their boundary conditions.

Two things to keep in mind:

  • this will not account for evaporation, but the air would cool next to those surfaces.
  • radiation models are not yet implemented in butterfly, and this would affect the distribution of the temperatures should the temperature differences be too large. For small differences it would still work.
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Yeah currently that’s about the maximum we can do, assign a (lower usually) temperature to the surface of the water. We would need both radiation and one of the more advanced heat transfer models (e.g. chtMultiRegionFoam) and probably some of the multiphase flow models (if we are talking about water vapors).

Myself I have almost never used that so I cannot really advise on specific options for the multiphase models. The heat transfer models would be much easier to implement (potentially) but they also bring a LOT of other considerations that can really not be automated (eg. y+ values for meshes).

As Butterfly matures, I’m sure we will implement more of this. For now, next steps include transient flows and MRF (which can be nice for fan simulations), along with adding the non k-epsilon models.

Kind regards,


I want to do water body in outdoor on my article too. the end I don’t understand what do I do? this is possible by Envi_met or Ladybug and butterfly…which one?
please help me for this.
Kind regards,

In response to that old reply, I would like to repeat the question. I work on outdoor comfort in rural areas and improvement by interventions. So landscape elements like water is pretty important for me. I used envi-met but I will focus on multi-criteria optimization so simulation times are way too high for me. Is there a way to model these surfaces and include the evapotranspiration to the simulation within ladybug components these days?

Thanks a lot,

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