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Values and Wall Functions

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Old   June 23, 2016, 12:24
Default Values and Wall Functions
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Kevin Cole
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Hello,

This is from the OpenFOAM C++ Source Code guide, which I tried to implement in my 0/nut
Code:
<patchName>
{
    type            nutUSpaldingWallFunction;
}
When I run the code, OpenFOAM complains that there is no specified value, despite the lack of it in the source guide.

My question is if there is a workaround for leaving out the value and having it work. If not, I would like to know what suitable values would be for a rough wall simulation.

Any help would be greatly appreciated.
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Old   June 24, 2016, 04:04
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You need to set a value for the boundary patch as well. Even though the quantity in question is going to be calculated using a wall function, you set its initial value. So it would be something like this:

Code:
<patchName>
{
    type            nutUSpaldingWallFunction;
    value          0;
}
Simply check settings in one of the many tutorials that come with OF installation!

Last edited by Zbynek; June 29, 2016 at 04:12.
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Old   June 24, 2016, 15:14
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Kevin Cole
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Thanks for the reply Zbynek! I tried that out and it indeed worked.

Do you by any chance know what the F3 coefficient in the kw SST model does?
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Old   June 29, 2016, 04:15
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Hi Kevin,

The answer on your question is hidden in the header file of the k-omega SST model.

Code:
Description
    Implementation of the k-omega-SST turbulence model for incompressible
    flows.
    Turbulence model described in:
    \verbatim
        Menter, F., Esch, T.,
        "Elements of Industrial Heat Transfer Prediction",
        16th Brazilian Congress of Mechanical Engineering (COBEM),
        Nov. 2001.
    \endverbatim
    with the addition of the optional F3 term for rough walls from
    \verbatim
        Hellsten, A.
        "Some Improvements in Menterís k-omega-SST turbulence model"
        29th AIAA Fluid Dynamics Conference,
        AIAA-98-2554,
        June 1998.
    \endverbatim
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