CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > FLUENT

UDS question

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Display Modes
Old   April 1, 2005, 02:12
Default UDS question
  #1
Z
Guest
 
Posts: n/a
How to access the previous iteration data of uds

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

Old   April 1, 2005, 07:45
Default Re: UDS question
  #2
ap
Guest
 
Posts: n/a
Yes, the value of the scalar you're solving for at the previous time step can be obtained using

C_UDSI_M1 (cell, thread, scalar)

Best regards, ap
  Reply With Quote

Old   April 1, 2005, 10:21
Default Re: UDS question
  #3
Z
Guest
 
Posts: n/a
what about steady state solver Then what does C_UDSI_M1 mean is it previous iterations.
  Reply With Quote

Old   April 1, 2005, 17:58
Default Re: UDS question
  #4
ap
Guest
 
Posts: n/a
In a steady calculation you can't access to the previous time step data, because it doesn't exist.

Regards, ap
  Reply With Quote

Old   April 2, 2005, 08:11
Default Reply to ap
  #5
Z
Guest
 
Posts: n/a
Hi, I posted this questions long back and saw your reply.

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

  Reply With Quote

Old   April 2, 2005, 14:45
Default Re: Reply to ap
  #6
ap
Guest
 
Posts: n/a
If you increase the verbosity parameter, you can see the order in which the equations are solved, and monitor the residuals at each single iteration.

However, UDS should be solved after other variables.

For your scalar equation, I should have more information, What kind of equation is it? What's its coefficients? What are the boundary conditions?

Best regards, ap
  Reply With Quote

Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Question about UDS diffusivity zhaohui FLUENT 0 August 18, 2010 21:43
question on "specified flux" BC for UDS ljp FLUENT 0 June 18, 2010 16:11
question about uds tanven FLUENT 1 October 27, 2009 09:55
A good question about UDS Z FLUENT 1 March 31, 2005 15:14
UDS question Z FLUENT 1 March 31, 2005 15:08


All times are GMT -4. The time now is 23:32.