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-   -   UDS question (https://www.cfd-online.com/Forums/fluent/36227-uds-question.html)

 Z April 1, 2005 02:12

UDS question

How to access the previous iteration data of uds

is it C_UDSI_M1(c,t,0) and this is just of time step ?

 ap April 1, 2005 07:45

Re: UDS question

Yes, the value of the scalar you're solving for at the previous time step can be obtained using

Best regards, ap

 Z April 1, 2005 10:21

Re: UDS question

what about steady state solver Then what does C_UDSI_M1 mean is it previous iterations.

 ap April 1, 2005 17:58

Re: UDS question

In a steady calculation you can't access to the previous time step data, because it doesn't exist.

Regards, ap

 Z April 2, 2005 08:11

1) I would like to know when UDS is solved at what positions scalar is solved is it after k and epsilon equation or before k and epsilon equation. 2) I wrote an UDS and it was not working fine it generally gives me values less than 0 and more than 1. When I browsed in this site I cam to know when scalar values are less than 0 then it should be set 0 and more than 1 value should be set to 1. Is this correct what I am doing?

3)When I used this setting discussed above Everything seems to be okay but the problem is URF in that case should not be more than 0.1 and if I use URF to be more than 0.1 then fluent gives me very big numbers e+20 something like that. So the problem is that simulation is very slow with URF is there any solution to this problem.

Your reply was 1) Go to Control -> Solution -> Multigrid and increase the verbosity parameter. (Can you explaine me more here)

2) What do you mean with less than 0 and more than 1? It depends on the problem you're solving. When you implement a UDS equation in FLUENT you should write it in its dimensional form. So the values of the variable are not bounded in the standard range [0; 1]. (I am solving for a scalar which is just values from 0 and 1)

Z

 ap April 2, 2005 14:45