CFD Online Logo CFD Online URL
Home > Forums > Software User Forums > OpenFOAM

Naca 0012 validation, Cd value is too high.

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

LinkBack Thread Tools Search this Thread Display Modes
Old   August 11, 2011, 06:06
Default Naca 0012 validation, Cd value is too high.
New Member
Join Date: Feb 2011
Posts: 13
Rep Power: 15
Peter88 is on a distinguished road
He everybody,

I am busy doing a Naca 0012 validation. First I started with the zero incidence angle. A Cmesh domain, with a lot of cells near the trailing edge. The Cd result that I get is: Cd of 0.02, which should be 0.008. I use a Re of 5e6. Does somebody got any tips, or have done a naca validation. What kind of turbulence model and wall function?

Best Regards,

Peter88 is offline   Reply With Quote

Old   August 11, 2011, 07:25
Senior Member
akidess's Avatar
Anton Kidess
Join Date: May 2009
Location: Germany
Posts: 1,377
Rep Power: 29
akidess will become famous soon enough
Using the search function you can find hundreds of threads on NACA validation, see e.g.
akidess is offline   Reply With Quote

Old   August 15, 2011, 10:54
New Member
Join Date: Aug 2011
Posts: 5
Rep Power: 14
gashishr is on a distinguished road
Which solver are you using?
gashishr is offline   Reply With Quote

Old   January 14, 2014, 08:55
New Member
shubham jain
Join Date: Dec 2013
Posts: 25
Rep Power: 12
shubham jain is on a distinguished road
i am validating my Cl and Cd values for NACA 0012. Can anybody provide me with a link or or exact Cd values?? I can find Cl values but i am unable to find Cd values of naca 0012.

Please help
shubham jain is offline   Reply With Quote

Old   January 21, 2014, 16:10
New Member
GregorS's Avatar
Gregor Seljak
Join Date: Oct 2010
Posts: 21
Rep Power: 15
GregorS is on a distinguished road
Cd values calculated with RANS models are usually higher than measured values from wind tunnel. RANS models trat boundary layer as turbulent over whole airfoil surface, whichisnt the case in reality. In reality, boundary layer is laminar in the front portion of airfoils and then becomes turbulent. Because scin frctioninlaminar boundary layer is lower than inturbulent one, drag values measured with experimant are lower than ones from CFD simulation.

To overcome this difference, sometimes a trip wire is attached to the leading edge of airfoil, which makes boundary layer turbulent already at the trailing edge. These results match much better with simulation.

You can get tripped data for NACA 0012 in:
N. Gregory in C. L. O’Reilly, Low-speed Aerodynamic Characteristics
of NACA 0012 Aerofoil Section, Including the Effects of Upper-surface
Roughness Simulating Hoar Frost

But your value of 0.2 is still to high. For Re=3x10^6 should be about 0.11 for tripped airfoil. I got good results with Spalart-Allmaras and k-omega SST model, both in high-Re and low-Re mode.

On the other side, Cd values obtained with LienCubicLowRe and NonLinearKEShih matches pretty good with non-tripped experimental data.
GregorS is offline   Reply With Quote


Thread Tools Search this Thread
Search this Thread:

Advanced Search
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 Off
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
How to import NACA 0012 Profile in Gridgen maplepink Main CFD Forum 17 May 7, 2013 13:01
NACA 0012 Case Will Not Converge dancfd OpenFOAM Running, Solving & CFD 6 November 14, 2011 19:09
naca 0012 validation case: wrong Cd vaina74 OpenFOAM Running, Solving & CFD 5 July 15, 2011 11:50
NACA 0012 simulation results Luis FLUENT 3 February 15, 2006 11:42
Multicomponent fluid Andrea CFX 2 October 11, 2004 05:12

All times are GMT -4. The time now is 12:14.