code_saturne User's Forum

Hello,

I'm trying to modify the 'cs_wall_functions_2scales_log' wall function.
I'm having some troubles to understanding some of the parameters inside the code.
Could someone help me to understand the meaning of them, formulae would be great too.

* \param[out] iuntur indicator: 0 in the viscous sublayer
* \param[out] nsubla counter of cell in the viscous sublayer
* \param[out] nlogla counter of cell in the log-layer
* \param[out] ustar friction velocity
* \param[out] uk friction velocity
* \param[out] ypup yplus projected vel ratio
* \param[out] cofimp \f$\frac{|U_F|}{|U_I^p|}\f$ to ensure a good turbulence production

Thank you very much,
Ionut

Can somebody help me?

Thank you,
Ionut

Hello,

In any case, for this type of development, I recommend looking at the source code for existing wall models to see how they work. This will provide the formulae you are looking for. Most of the code for these models is quite short (and more importantly does not have strong dependencies on other parts of the code) so it should not be too difficult.

I believe the counters are simply that: counters that are used for logging so that in the listing you will have more information on how many boundary cells are in each type of zone; the code can work without those but it can be very useful when trying to understand how/why a model behaves on a given mesh and flow field.

ustar and uk should match the litterature,

For the last 2 terms, I am not sure, so checking the source code is again the best (easiest and safest) solution.

Regards,

Yvan