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2D NACA 0012 Airfoil Validation Case

SSTm Model Results
 

Link to SSTm equations

Previously on this page the results were reported as SST solutions, but more properly they should be referred to as SSTm. Essentially no difference is expected.

Note that thorough grid studies were not performed for validation cases such as this one. Some effort was made to ensure reasonable grid resolutions, but there may still be small noticeable discretization errors. Therefore, these validation results shown should be considered representative, but not "truth." (See the NACA 0012 Numerical Analysis Case for a representative verification exercise of this airfoil case.)

Above SSTm results are from three independent CFD codes: CFL3D (NASA LaRC, USA), FUN3D (NASA LaRC, USA), and NTS (NTS, Russia). Both CFL3D and FUN3D used freestream turbulence intensity=0.052% and freestream turbulent viscosity (relative to laminar)=0.009 (additional details can be found in the CFL3D User's Manual, Appendix H). Please read note 5 on Notes on running CFD page. The codes all used the same 897x257 grid, and gave very close results (max less than 1% difference in lift, 5% difference in drag). These small differences are due to discretization errors, iterative convergence differences, boundary condition differences, and/or possible code-to-code implementation-detail differences. (Limited tests with CFL3D indicate that the effects of discretization errors on lift and drag for the 897x257 grid are smaller than the max differences listed above. However, complete grid studies involving all codes would be required to learn the effects for each code.) See NACA 0012 Numerical Analysis Page for more discussion about numerical issues associated with the NACA 0012 airfoil case. Note that these are compressible code results at "essentially incompressible" conditions of M=0.15. There may be a very small influence of compressibility. Note that use of SST, SSTm, SST-V, or SST-Vm yield very close results for this case. Only the CFD data files from CFL3D's SST results are given here for reference: n0012clcd_cfl3d_sst.dat, n0012cp_cfl3d_sst.dat, and n0012cf_cfl3d_sst.dat. A typical CFL3D input file is: n0012_cfl3d_typical_sst.inp. A typical FUN3D input file is: fun3d.nml_typical_sst_2.

Summary of CFD SST Results:

CODE	CL (alpha=0)	CL (alpha=10)	CL (alpha=15)	CD (alpha=0)	CD (alpha=10)	CD (alpha=15)
CFL3D	approx 0	1.0778	1.5068	0.00809	0.01236	0.02219
FUN3D	approx 0	1.0840	1.5109	0.00808	0.01253	0.02275
NTS	approx 0	1.0765	1.5100	0.00809	0.01251	0.02187

 

Behavior of model near CLmax:

The behavior of the SSTm model near maximum lift for this 2-D case is shown in the following plots (CFL3D only). The cases were run every 1 deg (starting at 15 deg.), at least until C_L,max was approximately attained. Note that the highest angle of attack run (alpha=19) did not converge well in this case. An approximate C_L,max range from experiments (McCroskey, AGARD CP-429, July 1988; also NASA TM 100019, October 1987) is highlighted in the first plot by green dashed lines. Note, however, that experimental data near maximum lift no doubt contains a significant degree of three-dimensionality. Also, these CFD results are still on the 897x257 grid, and there is likely to be significantly more grid sensitivity for the higher angles of attack than for the lower angles of attack shown above. Therefore, the results below should only be viewed qualitatively.

 
 

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Last Updated: 03/04/2025