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4-Participant
June 27, 2024
Solved

y+, intelligent wall formulation, BL questions about Creo Flow

  • June 27, 2024
  • 3 replies
  • 2009 views

I'm starting to play around more with Creo Flow and am a little unclear about the available options for modeling the boundary layer

1) Is there an option to select a laminar boundary layer or is everything just modeled using a turbulent BL with k-eps formulation?

2) Are there other turbulent BL options other than k-eps?

3) does the k-eps BL option include an intelligent wall formulation, where the cells in the BL that have a y+ lower than some cutoff value are ignored?

4) What are some of the levers that I can pull to achieve y+ values in the typically desired range of 13-31?

Thanks!

MArk

 

 

Best answer by cfdgeek

Hi 

 

1) Is there an option to select a laminar boundary layer or is everything just modeled using a turbulent BL with k-eps formulation?

yes, in the physics module, just add flow without turbulence, then you don't have turbulence models in the project.

2) Are there other turbulent BL options other than k-eps?

yes, we have k-e and also RNG and realizable k-e, but k-e should fit be a good fit for most of cases. 

3) does the k-eps BL option include an intelligent wall formulation, where the cells in the BL that have a y+ lower than some cutoff value are ignored?

Yes. we already consider y+ range and turbulence BL structure in our wall functions. e.g. log low and sub layers

4) What are some of the levers that I can pull to achieve y+ values in the typically desired range of 13-31?

You can try reduce the surface mesh size and also consider reduce the aspect ratio of the mesh. all those meshing controls can be found in mesher properties. 

 

Hope this helps!

3 replies

Community Moderator
July 4, 2024

Hi @MW_10424792,

Thank you for your question. 

Your post appears well documented but has not yet received any response. I am replying to raise awareness. Hopefully, another community member will be able to help.

Also, feel free to add any additional information you think might be relevant. It sometimes helps to have screenshots to better understand what you are trying to do.

 

Regards,

Anurag 

4-Participant
July 8, 2024

Many thanks for your help!

cfdgeek13-AquamarineAnswer
13-Aquamarine
August 24, 2024

Hi 

 

1) Is there an option to select a laminar boundary layer or is everything just modeled using a turbulent BL with k-eps formulation?

yes, in the physics module, just add flow without turbulence, then you don't have turbulence models in the project.

2) Are there other turbulent BL options other than k-eps?

yes, we have k-e and also RNG and realizable k-e, but k-e should fit be a good fit for most of cases. 

3) does the k-eps BL option include an intelligent wall formulation, where the cells in the BL that have a y+ lower than some cutoff value are ignored?

Yes. we already consider y+ range and turbulence BL structure in our wall functions. e.g. log low and sub layers

4) What are some of the levers that I can pull to achieve y+ values in the typically desired range of 13-31?

You can try reduce the surface mesh size and also consider reduce the aspect ratio of the mesh. all those meshing controls can be found in mesher properties. 

 

Hope this helps!

4-Participant
August 26, 2024

Thanks โ€“ thatโ€™s very helpful!

Mark L. Whittum, P.E.

Senior Principal Mechanical Engineer


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Community Moderator
August 29, 2024

Hello @MW_10424792

 

It looks like you have a response from a community member. If it helped to answer your question please mark the reply as the Accepted Solution. 

Of course, if you have more to share on your issue, please let the Community know so other community members can continue to help you.

Thanks,
Vivek N.
Community Moderation Team.

4-Participant
September 24, 2024

Very helpful - thanks a bunch!

 

Mark