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Old   February 28, 2024, 06:24
Default nut, nutilda
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Hello, I want to realize an aerodynamic solution for incompressible flows under standard atmospheric conditions. I use simpleFoam as a solver. What should I enter in the Nut and Nutilda section?

rho [1 -3 0 0 0 0 0] 1.225;

nu [0 2 -1 0 0 0 0] 1.461e-05;

p: 101325 Pa
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Old   February 28, 2024, 06:44
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The short answer is "suitable values".

In other words, you need to calculate what these values are for your flow scenario.
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Old   February 28, 2024, 06:55
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Quote:
Originally Posted by Tobermory View Post
The short answer is "suitable values".

In other words, you need to calculate what these values are for your flow scenario.
how to calculated nut and nutilda ? The default state is 0.14. How can I calculate this for my own problem ?

As a second question, I would be glad if you could answer it. I want to perform an aerodynamic analysis in openfoam. I making simpleFoam solver. There is no T file in folder 0, can I create it myself and enter the temperature value?
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Old   February 28, 2024, 07:09
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Originally Posted by onurcanpiskin View Post
how to calculated nut and nutilda ? The default state is 0.14. How can I calculate this for my own problem ?
First you need to read up on what these quantities are, then you need to do the research to allow you make a sensible judgement on their values for your flow problem. The values vary from case to case depending on your flow scenario ... there is no single "correct value".

Quote:
As a second question, I would be glad if you could answer it. I want to perform an aerodynamic analysis in openfoam. I making simpleFoam solver. There is no T file in folder 0, can I create it myself and enter the temperature value?
No. simpleFoam is an incompressible solver and does not deal with temperature; you need a different solver. You could solve for temperature as a passive scalar, but in that case it would not affect the air density.
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Old   February 28, 2024, 07:18
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Quote:
Originally Posted by Tobermory View Post
First you need to read up on what these quantities are, then you need to do the research to allow you make a sensible judgement on their values for your flow problem. The values vary from case to case depending on your flow scenario ... there is no single "correct value".


No. simpleFoam is an incompressible solver and does not deal with temperature; you need a different solver. You could solve for temperature as a passive scalar, but in that case it would not affect the air density.
I understand sir. Thank you very much. I ask you small other questions

Let's say I have determined the appropriate solver. And I am interested in T,p,U,nut,Nutilda files. But there are also files such as k and omega in the 0 folder of that solver. Can I delete them? After deleting them from there, do I need to delete them from somewhere else, for example from the fvSolution file?
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Old   February 28, 2024, 08:09
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Originally Posted by onurcanpiskin View Post
Let's say I have determined the appropriate solver. And I am interested in T,p,U,nut,Nutilda files. But there are also files such as k and omega in the 0 folder of that solver. Can I delete them?
Again, the simplest way of answering this question for yourself is to look at the solver coding (if you are going to use OpenFOAM, then there is no way out of this I am afraid!). This will show you which variables the solver is using, although the turbulence variables depend on what turbulence model you have chosen.

A short cut is to delete the files and then try to run the solver - it will then crash & complain if it is missing a file.

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After deleting them from there, do I need to delete them from somewhere else, for example from the fvSolution file?
Nope - you can leave in the info in fvSolution/fvSchemes - info for unused variables is ignored.

Good luck my friend.
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