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

Separation of Flow problems

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   March 16, 2006, 12:10
Default Separation of Flow problems
  #1
Simon c
Guest
 
Posts: n/a
Hello all, an aerofoil iam looking into is showing some odd results, namely the flow is far to attached to the aerofoil where the flow has slowed. From experience and using xfoil i should expect to see a seperation of the flow. is there any way of forcing fluent to stop being so generous in attaching the flow. Any ideas would be welcome, iam using standard K-e model with Y+ values all between 30-70 and with a very low speed of 15m/s. Yours S
  Reply With Quote

Old   March 16, 2006, 14:01
Default Re: Separation of Flow problems
  #2
MOHAMMED
Guest
 
Posts: n/a
try to increase the velocity to 80 m/s and the angle of attack and see what will happen

  Reply With Quote

Old   March 16, 2006, 15:16
Default Re: Separation of Flow problems
  #3
Razvan
Guest
 
Posts: n/a
The answer to your problem is very simple: switch standard k-e with SST-kw. The underprediction of separated flows is a well known problem of standard k-e turbulence model. Another advice would be to use a y+=1 mesh instead, the results will surely improve.

Razvan

  Reply With Quote

Old   March 19, 2006, 12:05
Default Re: Separation of Flow problems
  #4
Simon c
Guest
 
Posts: n/a
Thanks for the replys. Should have mentioned thats its a car aerofoil so that pressure drag dominates even at 0 angle of attack. Changed the value of length scale within the inlet boundary condition and iam now seeing what i expected. I thought orginally that I should insert a value of L= to my aerofoil length, but using a smaller value I get results I expected. Why is this?? I will have a go with the other turbulence model but my results are good enough now to prove my evaluation of how poor this aerofoil is! Thanks again Yours Simon
  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
Problems with a compressible shear flow ivan_cozza OpenFOAM Running, Solving & CFD 2 May 26, 2010 10:08
Problems modeling subsonic engine air inlet with flow separation TWaung CFX 2 March 29, 2009 18:42
unsteady flow problems Daniel FLUENT 0 January 25, 2009 23:54
fluid flow fundas ram Main CFD Forum 5 June 17, 2000 21:31
Flow visualization vs. Calculated flow patterns Francisco Saldarriaga Main CFD Forum 1 August 2, 1999 23:18


All times are GMT -4. The time now is 20:45.