SST with scalable wall treatment, is it possible?
 

Hi
In CFX-pre version 15 for wall function only automatic choice is available. But in CFX theory guide is mentioned that scalable model can be enabled by by extracting the CCL and changing the Wall Function from Automatic to Scalable. Ive done this and also I wrote Rough Wall Minimum Yplus = 2.5 in the next line, but when I imported the modified ccl into CFX-pre it gave the following error:

The parameter "Option" in "/FLOW:Flow Analysis 1/DOMAIN:fluid/FLUID MODELS/TURBULENT WALL FUNCTIONS" has the value "Scalable". This does not match any of the allowed values: "Automatic, User Defined".

Whats the problem?

The user interface does not support Scalable wall function for SST.

The theory guide is providing a workaround to be used for the solver run only. The user interface is displaying that such combination is not supported, though is syntactically correct.

Ignore the error, write the definition file and run the calculations.

Anytime you use this type of workaround, you must be very careful the solution behaves as expected. There must be a reason is not in the user interface.

I tested. You are right. In solver output file scalable option is wrote for turbulence wall function.
I appreciate you.

Modifying CFX downward shift for rough walls
 

Hi
As you know the CFX downward shift for rough walls is expressed as image attached:
But in correlations presented in Lingrani and Moffat, this shift differs from what CFX uses, specially in transitional-roughness regime.
Is it possible to change this equation in an easy way?
The difference between these two is also brought in the other picture.
http://www.cfd-online.com/Forums/dat...AAAElFTkSuQmCChttp://www.cfd-online.com/Forums/dat...AAAElFTkSuQmCC