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

How to define a transient species source term?

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

Reply
 
LinkBack Thread Tools Display Modes
Old   March 5, 2011, 22:59
Default How to define a transient species source term?
  #1
Member
 
Join Date: Mar 2011
Posts: 38
Rep Power: 6
aleisia is on a distinguished road
In my transient analysis, I want to set my species source in a way like this:
turn it on for 1s, then switch it off. I guess there are two ways to do this, first is, to run the simulation to 1s (with a time interval ,say,0.01s) and stop it, change the BC to 0m/s and carry on.

Second is, write a udf source macro for my source, but I don't know how to, if you could share with me a good source code, I would be greatly indebted!

Also, I have some doubts about setting source term:
I set the surfaces as velocity inlet instead of setting the volume as fluid and a source term, because I don't know how to set UDF source terms. I actually tried to do that, and I can set it as source term and set the mass term as, say, 0.1kg/m^3s (choose CONSTANT) and species term as the same number 0.1kg/m^3s. I don't care much about the momentum input this release of substance brings along, so leave it alone. But according to what I found from other discussions, it seems that setting like this doesn't work, and I have to do it through UDF. I don't know if I'm getting this picture right, so you know, please tell me.
aleisia is offline   Reply With Quote

Old   March 7, 2011, 01:55
Default
  #2
Senior Member
 
Join Date: Jun 2009
Posts: 100
Rep Power: 8
alastormoody11 is on a distinguished road
Hi,

A simplistic strategy for writing your macro is to record a journal file in which you manually set the source term and use it as a base for writing your UDF.

My suggestion would be to access your physical time and then put the source term inside an if else setting so that it becomes 0 once your physical time exceeds 1s.
alastormoody11 is offline   Reply With Quote

Old   March 7, 2011, 20:41
Default
  #3
Member
 
Join Date: Mar 2011
Posts: 38
Rep Power: 6
aleisia is on a distinguished road
Quote:
Originally Posted by alastormoody11 View Post
Hi,

A simplistic strategy for writing your macro is to record a journal file in which you manually set the source term and use it as a base for writing your UDF.

My suggestion would be to access your physical time and then put the source term inside an if else setting so that it becomes 0 once your physical time exceeds 1s.
Hi, thanks for your reply. As I've no idea how to "record a journal file", do you know if there is mature set of source macro code for my situation? Of any tutorial besides the fluent udf manual?

Thanks!
aleisia is offline   Reply With Quote

Old   March 7, 2011, 23:58
Default
  #4
Senior Member
 
Join Date: Jun 2009
Posts: 100
Rep Power: 8
alastormoody11 is on a distinguished road
this is the first link that pops up after a google search for how to record a journal file in FLUENT:http://www.cfd-online.com/Wiki/Fluent_FAQ

Cant you even do a google search

I mean common
alastormoody11 is offline   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
Large source term in species equation MACFD FLUENT 4 January 4, 2011 15:16
Reaction Source Term in Steady Species transport equation cfdvenkatesh Main CFD Forum 0 August 19, 2010 09:28
Installing OF 1.6 on Mac OS X gschaider OpenFOAM Installation 140 June 19, 2010 09:23
How can I get Help? Scalar transport_source term lig Fluent UDF and Scheme Programming 0 May 9, 2010 22:30
Free surface boudary conditions with SOLA-VOF Fan Main CFD Forum 10 September 9, 2006 12:24


All times are GMT -4. The time now is 10:51.