# Fluent Singhal cavitation model?

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January 7, 2015, 13:01
Fluent Singhal cavitation model?
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Behrooz Jamshidi
Join Date: Apr 2013
Posts: 83
Rep Power: 5
Hi
I am modeling cavitaion on naca66(mod).I have got the results from fluent and after time-consuming convergency the results are ok as in Singhal paper. But when I implement the formulation of Fluent(I have attached the formulation) of Singhal model into CFX I get good convergency but results a bit different.
what is the k in the formulation(max(1,sqrt(k))?. In Singhal paper has mentioned it can be turbulent kinetic energy but I think there are something different in Fluent formulation.
so
1- What is k in the formulation?
2- Do u have any experience of Singhal model with udf to get the same results as its default
Attached Images
 singhal.jpg (23.0 KB, 30 views) singhal2.jpg (22.3 KB, 27 views)

 January 7, 2015, 13:47 #3 Member   Behrooz Jamshidi Join Date: Apr 2013 Posts: 83 Rep Power: 5 Thank you Daniele I have the paper and it has been cited in so many papers. Unfortunately in a lot of papers, they have presented different formulation from Singhal and reference into one paper.Fluent is one of them, it has max(1,sqrt(k)) but nowhere in that paper such a term is not presented in its formulation. I have checked the math but I think the problem is with numerical procedure as Fluent user guide says it has different numerical procedure. And there should be a reason that it has poor convergency!do u know why?

 January 7, 2015, 15:01 #4 Senior Member     Daniele Join Date: Oct 2010 Location: Italy Posts: 993 Rep Power: 17 Yes, I understand what you mean. The original model is that on the article (square root (k), not max term); I think the "max" term is introduced for stability purposes. Take into account also that this model is a semi-empirical model, as it has tuning constants Fvap and Fcond, which you can change as you want. __________________ Google is your friend and the same for the search button!

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