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

Reversed flow over airfoil in ANSYS

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

Reply
 
LinkBack Thread Tools Display Modes
Old   April 30, 2014, 11:29
Default Reversed flow over airfoil in ANSYS
  #1
New Member
 
Shoaib
Join Date: Apr 2014
Posts: 3
Rep Power: 2
shoaib_aero is on a distinguished road
I am simulating flow over an RAE2822 airfoil with forward sweep configuration.
After applying all boundary conditions, when I run the solver, everything is normal except in post processing, the lower pressure is on the lower camber of airfoil instead of upper camber. The values seem logical and correct except that they should be on opposite cambers. I am confused about this.

Any suggestions and advice would be really appreciated.
Attached Images
File Type: jpg reverse 2.jpg (73.7 KB, 24 views)
shoaib_aero is offline   Reply With Quote

Old   April 30, 2014, 19:01
Default
  #2
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 9,551
Rep Power: 76
ghorrocks has a spectacular aura aboutghorrocks has a spectacular aura aboutghorrocks has a spectacular aura about
Are you sure you have the angle of attack right? The airfoil looks pitched down to me, and that would explain the low pressure on the bottom side.
ghorrocks is offline   Reply With Quote

Old   May 1, 2014, 02:54
Default
  #3
New Member
 
Shoaib
Join Date: Apr 2014
Posts: 3
Rep Power: 2
shoaib_aero is on a distinguished road
It is a twisted wing where the tip is at angle of 11 degree with the root. And the wing is kept at an angle of attack of 1.5 degrees.
Even if the wing is pitched down, the pressure has to be lower on the upper surface to produce lift.
The situation in the picture would mean that the wing will drop down more instead of lifting in this condition which makes no sense.
shoaib_aero is offline   Reply With Quote

Old   May 1, 2014, 09:10
Default
  #4
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 9,551
Rep Power: 76
ghorrocks has a spectacular aura aboutghorrocks has a spectacular aura aboutghorrocks has a spectacular aura about
If the wing is twisted then one section of the wing can produce upwards lift and another produce downwards lift.
ghorrocks is offline   Reply With Quote

Old   May 1, 2014, 21:43
Default
  #5
New Member
 
Shoaib
Join Date: Apr 2014
Posts: 3
Rep Power: 2
shoaib_aero is on a distinguished road
I changed the angle of attack of the wing to 3 degree and still getting the same result.

Any advice
Attached Images
File Type: jpg reverse3.jpg (50.0 KB, 7 views)
shoaib_aero is offline   Reply With Quote

Old   May 1, 2014, 21:50
Default
  #6
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 9,551
Rep Power: 76
ghorrocks has a spectacular aura aboutghorrocks has a spectacular aura aboutghorrocks has a spectacular aura about
I still think what you are seeing is real.

But your question really is "I think my simulation is inaccurate". That is an FAQ: http://www.cfd-online.com/Wiki/Ansys..._inaccurate.3F

There are millions of benchmark results for flow over airfoils. You should do a validation that you can accurately produce the lift and drag of a foil you have good benchmark results on before attempting your configuration. Otherwise how do you know whether your result is accurate or not? And this is exactly the problem you are now in.
ghorrocks is offline   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 in Outlet Steve FLUENT 18 March 30, 2013 08:50
Reversed flow cyclone Mohsin FLUENT 0 August 7, 2012 20:46
Review: Reversed flow CRT FLUENT 0 July 20, 2012 13:03
About the invisd flow around an airfoil maximus Main CFD Forum 1 July 16, 2005 15:04


All times are GMT -4. The time now is 08:29.