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

UDS

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   May 14, 2003, 03:52
Default UDS
  #1
sebeci
Guest
 
Posts: n/a
Hello to all

I want to solve two coupled equations in the form bellow by UDS but for introducing the time derivative we have three options in Fluent: Default,none and UDF.

If I choose Default, both of time derivative will remain.

so we have

d(fi1)/dt-D.(gama1.D(fi1))=Source1

d(fi2)/dt-D.(gama2.D(fi2))=Source2

If I choose None ,both of time derivative will omit.

0 -D.(gama1.D(fi1))=Source1

0 -D.(gama1.D(fi1))=Source1

In UDF I couldn't do that. So,how do I define this two equations?

d(fi1)/dt-D.(gama1.D(fi1))=Source1

0 -D.(gama2.D(fi2))=Source2

Thanks in addvance

  Reply With Quote

Old   May 14, 2003, 09:15
Default Re: UDS
  #2
jeroen
Guest
 
Posts: n/a
In the UDF DEFINE_UDS_UNSTEADY(name, c, t, i, apu, su) the i is the counter of the UDS's. So with an if statement you can define two different time derivatives for your two UDS's.

More information on fluent 6.1 UDF-manual chapter 4.3.20.
  Reply With Quote

Old   May 14, 2003, 09:31
Default Re: UDS
  #3
sebeci
Guest
 
Posts: n/a
Thanks for your reply But,If I set apu and su to zero, It takes an error and gives AMG error.

  Reply With Quote

Old   May 14, 2003, 12:26
Default Re: UDS
  #4
jeroen
Guest
 
Posts: n/a
Take for the option time derivative for UDS none and incorporate the time derivative of one UDS in a define_source because the two terms A and B of a source term are equal to su and apu.
  Reply With Quote

Old   May 15, 2003, 01:33
Default Re: UDS
  #5
sebeci
Guest
 
Posts: n/a
Thanks

But,how could I define time derivative.

  Reply With Quote

Old   May 15, 2003, 06:45
Default Re: UDS
  #6
jeroen
Guest
 
Posts: n/a
The example in the udf manual for DEFINE_UDS_UNSTEADY is nothing more than the time derivative rewritten to use it in that UDF. So you can just copy that.
  Reply With Quote

Old   May 17, 2003, 06:20
Default Re: UDS
  #7
sebeci
Guest
 
Posts: n/a
Thanks again But,If you can please explain about it more. If you have any example please write it down.

sebeci,
  Reply With Quote

Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
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 Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
UDS Flux Function Choice Yang Chung FLUENT 1 November 17, 2015 02:14
PEM modeling UDS diffusivity in mixture gemini FLUENT 6 August 7, 2012 08:37
fixed value in the domain for a UDS in case of multiphase flow swati_mohanty FLUENT 2 November 30, 2010 04:17
Doubts UDS Flux, UDS Unsteady for VOF model kel85uk FLUENT 0 March 17, 2010 09:53
A good question about UDS Z FLUENT 1 March 31, 2005 16:14


All times are GMT -4. The time now is 22:50.