CFD Online Discussion Forums - Lift coefficient with my 2.5D airfoil model never matches the experimental data.

Hi all

I have a problem in simulating 2.5 d airfoil particularly in lift coefficient.

I'm doing fluent to simulate Airfoil naca 4412 in water-liquid medium.

I have following conditions.

Mesh : ICEM unstructured mesh, C-H grid(L=3.85m,H=1.8m,T=0.4m) ( 3d from 2d by extrusion)
AOA : 7 degree
velocity : 4.5 m/s
length of chord : 0.3 m
Reynolds Number : About 1.2*e6
steady : k-w sst (2nd order)
reference values : Area =0.12 m^2 length =0.3 m and all others are on default settings)

I currently get lift coefficient something like 0.8.
Before the extrusion to 2.5D in z-axis, i used to get around 1.15, which was very close to the experiment references.

My guessing is
1. wrong mesh.
2. wrong input for the reference values in fluent
3. just not right to expect correct simulation with 2.5d

HELP. and as it is a thread, any discussions with replies would be very helpful for me.