Low Reynolds Number
 

Hi,
Im doing a CFD analysis on a NACA 0012 wing, with a AR of 5.0 at a Re number of 80000. I am validating it with an experimental data. Im still unsure which model I have to be using , whether to go with laminar or use turbulent BL. When I have used , laminar model, the lift coefficients matched, but the drag coefficients are far way off.
Experimental @ 5 degrees
Cl - 0.4, cd -0.12.
My analysis
Cl -0.38, cd -0.06.
Any help in helping me solve this, is deeply appreciated

I guess you could use a low-Reynolds Turbulence model such as k-omega sst. Those are usually good for external aero purpose. That being said, in my experience I've found that it's always hard to match the drag values.

Iv tried that too, Iv played with the turbulence intensity and viscosity ratio too, still no avail , is there a limiting factor for Tu?

What does your grid look like? That's more than likely the problem.

Could the Turbulence Suppression model help in this problem?

http://www.4shared.com/folder/prFsZuQ1/_online
I have 300 grid points on the airfoil, and y+ = 0.8,
Regarding the grid, my only question, shd i keep dropping the y+ value, to see if my results would get any better?

Yes, i have used Turbulence Suppression Model, but the answers still did not change. I am running this simulation in Star CCM+, and i used, SA model, and tried playing with turbulence viscosity ratio, the Cd value increased to 0.89, but I didnt see any major changes,

You're doing LES for this?

I am doing RANS for this

I thought the turbulent suppression model was for LES.

Anyway, can you show me the grid?

Your near-wall layers seem to be really coarse. What is your wall y+?

I have kept it as 0.5

same problem different issues
 

hello Isaac
we're you able to resolve?
in my case drag coefficient is captured with minimal error of 1-3% whereas lift coefficient is way off. any help or suggestions please