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

boundary conditions compressible flow

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   June 7, 2006, 11:55
Default boundary conditions compressible flow
  #1
newposter
Guest
 
Posts: n/a
hi,

I want to simulate a shock in laval nozzle with my pressure-correction based SIMPLE code. I want to prescribe at Inlet: u,v,w and T at the Outlet: p_Stat

I can`t get convergence, the residuals are oszillating.

What can I do, please help?!

  Reply With Quote

Old   June 7, 2006, 21:44
Default Re: boundary conditions compressible flow
  #2
khai ching
Guest
 
Posts: n/a
What if you try to fix the stagnation properties at the inlet, e.g. Total Pressure, Total Temperature as well as the flow angle
  Reply With Quote

Old   June 8, 2006, 02:45
Default Re: boundary conditions compressible flow
  #3
newposter
Guest
 
Posts: n/a
That`s possible and working! My question is only if it`s possible to fix u,v,w and T and to get results with shocks and so on... Thank`s...
  Reply With Quote

Old   June 9, 2006, 16:41
Default Re: boundary conditions compressible flow
  #4
Mani
Guest
 
Posts: n/a
I don't see the point of doing that. The total pressure and total temperature are "natural" inlet conditions, because they are usually known from experiments, and they can be viewed as independent from the exit static pressure. Inlet flow angles are quasi known because of the duct geometry. On the other hand, the inlet velocity is not usually known in internal flow problems. Think physically: Flow is determined by pressure gradients, especially in internal flow, and your CFD should be driven by a natural condition. You ought to have some information on (total) pressure at the inlet. As a general remark: The number of conditions that you need to provide depend on the number of characteristics traveling into/out of the domain at the boundary, and that number is well known. However, the number alone does not guarantee convergence, or even existence of a unique solution. You have to choose a reasonable (preferably physical) combination of boundary conditions.
  Reply With Quote

Old   June 16, 2006, 17:10
Default Re: boundary conditions compressible flow
  #5
newposter
Guest
 
Posts: n/a
Thank you very much!!
  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
Wind turbine simulation Saturn CFX 58 July 3, 2020 01:13
Domain Imbalance HMR CFX 5 October 10, 2016 05:57
boundary conditions for 3D channel flow with heat transfer Aloex FLUENT 1 February 22, 2011 12:28
boundary conditions for boundary layer flow A. Al-zoubi CFX 0 November 3, 2007 07:11
compressible flow boundary conditions yangqing FLUENT 2 January 22, 2002 10:19


All times are GMT -4. The time now is 12:52.