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

the difference profile in the empty domain

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   August 24, 2006, 07:07
Default the difference profile in the empty domain
  #1
justin
Guest
 
Posts: n/a
Hello,

My study is on neutral atmospheric boundary layer wind tunnel. the inlet boundary was well known as U(z)=u*ln(z/z0)/k, outlet as outflow,sides and top as symmetry. z0, k and eps were got from the previous wind tunnel test.

Realisable k-eps,two layer wall funciton,smooth wall, structured mesh and second order were used in the empty domain.

After convergence, there was a large difference between inlet profile and outlet profile. Then grid was refined, but the problem still existed.If I use the cyclic conditoin between inlet and outlet, the constant profile can be got, but it was not what I wanted.

How can I achieve the consant profile in the empty domain?

your comments will be appreciated

Justin

  Reply With Quote

Old   August 25, 2006, 07:32
Default Re: the difference profile in the empty domain
  #2
justin
Guest
 
Posts: n/a
Now I found the reason, which was related to the epsilon. the well known equation eps=u*/(kz)made this problem, but it is difficult to solve. If we use the equation eps=Cu^(3/4)*k^(3/2)/l, eps looks like a constant, but accturally it is a variable with the vertical. also l and Cu is a changeable constant with the condition.

How do you describe the eps? please give any comments.

Thanks

Justin
  Reply With Quote

Reply


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 in setting the domain to empty Prince OpenFOAM 5 May 6, 2011 14:39
CFX domain comparison Kiat110616 CFX 4 April 3, 2011 23:43
How to model the NR eqns in a domain with empty space Vasilis Main CFD Forum 1 April 14, 2009 05:35
[Domain]Three different Domain Young CFX 3 April 27, 2008 15:11
How to form a constant profile in the empty domain justin FLUENT 1 August 23, 2006 09:43


All times are GMT -4. The time now is 08:34.