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December 23, 2021, 16:15 |
Y+ for heat transfer from the walls
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#1 |
New Member
Reza
Join Date: Dec 2021
Posts: 2
Rep Power: 0 |
Hello friends
I am new to simulating with Ansys Fluent. I have a question about the range of y+ and the turbulency model to be used. I want to simulate airflow inside a spiral channel with constant heat flux on the walls. As I read in the articles, the y+ should be below 1 for heat transfer simulation. On the other hand, for the k-e turbulency model, y+ should be 30 to 300. I want to know what do you suggest for this problem? Which y+ and turbulence model should I take? Many thanks for considering my request. |
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December 23, 2021, 17:45 |
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#2 |
Senior Member
Lucky
Join Date: Apr 2011
Location: Orlando, FL USA
Posts: 5,674
Rep Power: 66 |
In general, lower y+ is always better assuming you use the appropriate wall treatment.
The standard k-epsilon model using specific wall functions should have a higher y+. And frankly, I don't know of anyone that actually prefers this particular asinine combination. Most people use better turbulence models and use the enhanced wall treatment (in other words, an all y+ approach). If you can afford the lower y+ ~ 1, go for it by all means. It's just better. No one will complain. |
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December 23, 2021, 19:57 |
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#3 |
New Member
Reza
Join Date: Dec 2021
Posts: 2
Rep Power: 0 |
Thank you, LuckyTran, for your answer. I also prefer to deal with y+ lower than 1. For this reason, I used inflation close to the walls to reduce y+. I used the k-omega SST turbulence model. For convergency, I had to use the first-order method for the density and energy; otherwise, the residuals wouldn't reach the proper value (e-3 for continuity, momentum, and turbulence, and e-6 for energy). Do you think my approach is good enough to achieve accurate results?
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December 29, 2021, 07:23 |
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#4 |
New Member
physics baali
Join Date: Nov 2020
Posts: 10
Rep Power: 5 |
i dont know exactelly but i think you must choose Y+=1
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