Implement swirl as "internal" BC with calculated u_axial
 

Hello everyone,

as you can see in the attched pdf-file, I want to calculate the case as follows:

A diffuser is determined in a water volume, the "global BCs" are the Velocity u=2m/s (Inlet) and p=0bar (Outlet). Now I want to implement a "swirl" as additional interior BC at an interface with the velocities (in cylindric coordinates) v_radial=1m/s and v_theta=0.8m/s, though v_axial should be the calculated u at this mentonoid interface!!
In fluent and OF it is possible to arranged that. But is this possible in CFX 13 too?And how can I implement it??

Thanks in advance.

Regards

Sorry, I forget the pdf....

Sounds like this should just be a momentum source term. Look it up in the documentation.

Hello,

thank you for your reply but there establish some problems with the momentum sources:

1) this is only for subdomains, not to use for Interfaces/BC (maybe I have overlook/missunderstood something)
2) I need velocities, not momentums


Regards

To fix 1 you just make the entire domain a subdomain. But the second part of your question is the crux of the problem, I cannot think of a way to make it act only at the interface and in the correct direction.

Question 2 is fine, a momentum source can specify velocities. The "momentum" refers to what equation it applies to, not what is applied.

OK,thank you for your answer!

Regards

Are you trying to simulate something which actually physically exists ? if, yes, what is the actual arrangement there ?