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Customize the Prandtl number in the k-epsilon mode |
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May 9, 2021, 00:05 |
Customize the Prandtl number in the k-epsilon mode
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#1 |
New Member
Nianqi Li
Join Date: May 2019
Posts: 1
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Hello experts,
I want to customize the Prandtl number in the k-epsilon model for liquid metal simulations. I have the correlation equations for the Prandtl number, but I have no idea which Prandtl number should I define. There are TKE Prandtl number, TDR Prandtl number, Energy Prandtl number and Wall Prandtl number in the Viscous Model dialogue box. I have read some threads in the forum, and I know that TKE refers to the effective Prandtl number in the equation of k, TDR refers to the effective Prandtl number in the equation of epsilon, and the Energy Prandtl number and Wall Prandtl number work in a similar way. So, should I define all four Prandtl number with the same correlation equations? Or I just need to define some of them? |
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May 10, 2021, 17:08 |
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#2 |
Senior Member
Lucky
Join Date: Apr 2011
Location: Orlando, FL USA
Posts: 5,754
Rep Power: 66 |
You said that you want to edit the turbulent Prandtl number in the k-epsilon equation... but there is a Prandtl number for k and a Prandtl number for epsilon. So you need to figure out what you actually want to do...
If you want to edit only the k-epsilon equation (which is actually two equations) you should not touch any of the other turbulent Prandtl numbers. I don't know what your correlation is but you may be looking to edit 1 or 2 turbulent Prandtl numbers but not all of them. If you have only one correlation then you probably only need to edit 1 of the numbers. But now you need to figure out if it's the TKE or TDR Prandtl number. So what is this correlation? Dig it up in the literature. If there is some theoretical background accompany it then it is usually quite easy to figure out. |
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November 20, 2021, 08:59 |
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#3 |
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Outside North America
Join Date: Nov 2021
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Hello, my friend! Now I have the same problem as you. I need to simulate the flow and heat transfer of liquid metal. Do you know where to define turbulent Prt in OpenFOAM?
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November 20, 2021, 09:01 |
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#4 | |
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Quote:
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November 20, 2021, 15:22 |
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#5 |
Senior Member
Lucky
Join Date: Apr 2011
Location: Orlando, FL USA
Posts: 5,754
Rep Power: 66 |
If you want to change the turbulent Prandtl number in the wall function, that is specified as the boundary condition property.
If you want to change the global turbulent Prandtl number in the turbulence model itself, that is specified in the turbulenceProperties dictionary and usually by declaring Prt. If in doubt, run your sim using printCoeffs to see what are the model coefficients for your particular turbulence model. |
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November 20, 2021, 23:11 |
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#6 | |
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Outside North America
Join Date: Nov 2021
Posts: 14
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Quote:
I want to change the globle turbulent Prandtl number in the turbulence model. But I still don't know where to go to modify. I've set printCoeffs to on, but there is no information about turbulent Prandtl number at the terminal. Do you know in which dictionary file this parameter can be changed. Thank you again! |
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Tags |
fluent, fluent - udf, prandtl number |
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