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

reversed flow

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

Reply
 
LinkBack Thread Tools Display Modes
Old   April 4, 2005, 07:23
Default reversed flow
  #1
matth3w
Guest
 
Posts: n/a
hi all,

i am a novice CFD user,investigating the flow separation around an airfoil. My biggest worry now is that these error messages regarding "reversed flows on outflow" keeps popping up. This causes my iterations,Cl and Cd to "oscillate" and will never converge or flatten out.

i have tried changing my BC from outflow to pressure outlet and increasing the distance between the airfoil and the BC, but to no avail.

I have exhausted all possible means,based on my limited knowledge, to correct this problem. Anybody please advise.....i seek your wisdom.

p.s - anybody reckons that the reverse flows have anything to do with meshing,grids and the likes?
  Reply With Quote

Old   April 4, 2005, 07:24
Default Re: reversed flow
  #2
matth3w
Guest
 
Posts: n/a
thanks heaps in advance!
  Reply With Quote

Old   April 4, 2005, 07:53
Default Re: reversed flow
  #3
Luca
Guest
 
Posts: n/a
What kind of bc are you using? pressure outlet I suppose...Try using the far-field bc. That warning will disappear! What's is your Mach no? Luca
  Reply With Quote

Old   April 4, 2005, 13:42
Default Re: reversed flow
  #4
swarup
Guest
 
Posts: n/a
Do not use Outflow if you observe a reverse flow. Outflow BC fails in such a case. For aerodynamic flows, Far Field BC is the appropriate choice. Pressure Outlet happens to be a better choice over Outflow in case of reverse flow. only requirement is that you should have some meaningful estimate of downstream pressure and temeprature (if you have energy equation).

Swarup.
  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
reversed flow free FLUENT 4 February 27, 2014 02:56
reversed flow during RNG in turbulence-k epsilon Suman Kandula FLUENT 4 April 2, 2012 07:12
Reversed flow...>>>Please HELP...! sushii FLUENT 14 October 29, 2007 05:27
reversed flow at velocity inlet / mass flow inlet ib FLUENT 1 March 26, 2007 13:11
reversed flow Sastry FLUENT 5 March 22, 2007 09:05


All times are GMT -4. The time now is 18:19.