CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   CD-adapco (http://www.cfd-online.com/Forums/cd-adapco/)
-   -   How to confine scalar to positive values (http://www.cfd-online.com/Forums/cd-adapco/54336-how-confine-scalar-positive-values.html)

Sheila January 24, 2005 22:53

How to confine scalar to positive values
 
Hi everyone,

I am writing the k-w SST model in STAR as 2 scalars. I know that the model already exists in STAR but for my work I need to model them as separete quantities.

At the moment one of te problems I am having is that the minimum value of my k is always a very small negative value rather than zero. Any idea on what I can do to make sure the minimum is zero? Thanks in advance for your help. Sheila

4xF January 25, 2005 14:57

Re: How to confine scalar to positive values
 
RCONS 64 2

Sheila January 25, 2005 16:04

Re: How to confine scalar to positive values
 
Thank you! :D

Sheila January 27, 2005 18:32

its not working...?!
 
Hi 4xF,

its not wroking...

I am still getting a negative number as the minimum.

Sheila

matej January 28, 2005 04:15

Re: its not working...?!
 
Hi,

Unfortunatelly - I cannot tell you, where I got this info, whether it was adapco-online.com, or support, but still: the 64 switch works like this:

Setting rcon 64 to 1 clips the scalars between 0 and 1 for density calculation only, rcon 64 2 additionally clips the scalar values. (This seems to work only for active scalars.)

So it need not work for you. Can you limit the scalar with min-max in your user routine?

If it goes negative too much, It might be better to find the problem(source goes wild, or something)- where it originates and not to cure the effect :o))

good luck

matej

Sheila February 1, 2005 15:06

Re: its not working...?!
 
Thank you :)


All times are GMT -4. The time now is 19:46.