I am trying to test benchmark cases with a new zero equation turbulence model. I want to test this on 2D and 3D cases using ANSYS Fluent. Is there a way to write a new solver model as a UDF and hook to ANSYS?
I think it is not possible because turbulence models in fluent are robust ones. You can do it in COMSOL, OpenFoam packages.
Hi Pratik,
You can add source terms to modify existing turbulence models. So in the extreme case, you can add sources terms so that all existing terms in the original equation be eliminated. Then you can add new terms to form your own turbulence model.
Hi,
Thanks for your solution. I wanted to however know if I could convert the one equation Spalart Allmaras to a zero equation turbulence model with a different equation for turbulent viscosity in the user defined function. I know this can be done but I am struggling with the method.
In the case of low-Reynolds-number k-e turbulence models you can modify or create your own turbulence models by using UDFs. You can turn off the equations for turbulent quantities and add the new ones assuming the turbulent quantities as new User Defined Scalars.
Hi Carla,
Thank you so much. This was exactly the track I was thinking on. Should I have problems building this, I will contact you.
I have bad experiences, all problem related to stability (think about gradient or some term which can generate infinity or too small values). But I tried implement my version of k-e. It is work for flat plate but did not for airfoil.
In my honest opinion, it could be quite complicated. This is deeply related to the robustness and overall strictness linked to Fluent equation modelling. Of course it depends on the model you're going to implement and on the amount of parameters you're going to define/change....one possible (but maybe only) path could be the addition and subtraction of the proper quantities as source terms through a UDF. But, once again, this could be really difficult or, even worse, impossible.
I think that the Carla's answer is good because it is possible to desactivate the Fluent turbulence models and instead, you can activate another model developed by yourself. Yo can do that by means of user defined functions (UDF) that must be compiled (see Fluent UDF's manual).
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