CFD Online Logo CFD Online URL
Home > Forums > Software User Forums > ANSYS > FLUENT

Hey Fluent Guru's!! Need help here!

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

LinkBack Thread Tools Search this Thread Display Modes
Old   July 3, 2006, 21:15
Default Hey Fluent Guru's!! Need help here!
Posts: n/a

I need to initialize a transient simulation of a fire model inside a compartment. Now, I don't really know what proper value to assign as a first value for K,e or w -in case of k-w model- for this room. The air inside the room is initially stangnant. Any ideas??

Cheers, Amr

  Reply With Quote

Old   July 4, 2006, 07:53
Default Re: Hey Fluent Guru's!! Need help here!
Posts: n/a
Of course, one is tempted to initialize using 0 everywhere, but that is not recomandable (phisically it makes all sense, but numerically it can generate instability in first iterations, even divergence). So, simply initialize using small values, which will quicly dissipate into the grid in the first 2-3 time steps, like 0.001 for k and 0.1 for e or w. It really doesn't matter that much!

  Reply With Quote

Old   July 4, 2006, 18:29
Default Re: Hey Fluent Guru's!! Need help here!
AR Smith
Posts: n/a
physically it does not necessarly make sense, you can have residual turbulence in a big room where people are walking, breathing, working, etc...
  Reply With Quote

Old   July 5, 2006, 02:15
Default Re: Hey Fluent Guru's!! Need help here!
Posts: n/a
We are talking about a fire simulation here, which I know from Amr that was simulated experimentally first, and physically speaking, there were no people in that room at the time of the experiment, hence no residual turbulence caused by walking, breathing, working, etc... Anyway, we must agree on something: without movement turbulence cannot exist (brownian motion is NOT turbulence), and that is what Amr said were the initial conditions. Thank you for your intervention, you would have been perfectly right if there were any people in that room, but it is not the case here.

Best wishes, Razvan
  Reply With Quote


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
Two questions on Fluent UDF Steven Fluent UDF and Scheme Programming 7 March 23, 2018 03:22
fluent parallel problem in win7 x64 system dunga82 FLUENT 8 April 19, 2012 20:23
What the differences flow equation of Fluent 6.3 and Fluent 12.1 opehterinar81 FLUENT 0 August 19, 2011 11:55
On Bug of Fluent 12.0 lzgwhy FLUENT 0 August 26, 2009 06:41
Advanced Turbulence Modeling in Fluent, Realizable k-epsilon Model Jonas Larsson FLUENT 5 March 13, 2000 03:27

All times are GMT -4. The time now is 22:12.