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

Accumulation term

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   June 19, 2008, 15:06
Default Accumulation term
  #1
Kushagra
Guest
 
Posts: n/a
Hi, I am not able to understand the meaning of following statements from the CFX-11 Solver Modeling guide Page 392

1) "For transient For transient runs, if convergence within a timestep is achieved in one coefficient iteration, this can lead to unexpected diagnostics for the accumulation term."

2) By default, the initial guess within a timestep is taken from the end of the previous timestep. For the First Order Backward Euler transient scheme, this leads to an accumulation term of zero, and for the Second Order Backward Euler scheme, the accumulation term has the opposite sign from expectation.

3) However, if the Second Order Backward Euler scheme is used with extrapolation as the initialization option, then the accumulation term is reasonable after one coefficient. Information on initialization setting is available.

I will be greateful to you if you can help me in understanding what do above statements mean?

Thanks so much in advance, Kushagra
  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
Problem of SOURCE term gradient in UDS wind Fluent UDF and Scheme Programming 6 December 1, 2022 15:21
momentum source term zwdi FLUENT 14 June 27, 2017 16:40
Large source term in species equation MACFD FLUENT 4 January 4, 2011 15:16
pressure gradient term in low speed flow Atit Koonsrisuk Main CFD Forum 2 January 10, 2002 11:52
bouyancy term in epsilon equation Michael Main CFD Forum 1 June 25, 1999 11:20


All times are GMT -4. The time now is 08:41.