Langley Research Center Turbulence Modeling Resource

 

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Return to: 2D NACA 4412 Airfoil Trailing Edge Separation Case Intro Page

2D NACA 4412 Airfoil Trailing Edge Separation Validation Case

BSLm Model Results
 

Link to BSLm equations

Previously on this page the results were reported as BSL solutions, but more properly they should be referred to as BSLm. 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."

BSLm results from CFL3D are shown from the second-finest grid (897x257). Uref in the plots has been scaled as described on the 2D NACA 4412 Airfoil Trailing Edge Separation Case Intro Page. CFL3D used freestream turbulence intensity=0.086% 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. On this grid level, standard lift and drag coefficients based on the freestream conditions listed on the Intro Page were:

• CL=1.7096, CD=0.02836, CDp=0.02090, CDv=0.007451 for CFL3D

It is important to note that the experimental u, v, and u'v' data were nondimensionalized with respect to a non-traditional velocity at a location only about 1 chord below and behind the airfoil. This is different from a traditional "freestream" value. As a result, u/Uinf and v/Uinf values from CFD need to be divided by roughly 0.93 in order to be comparable to the experimental normalization u/Uref (where Uinf is the usual farfield freestream value and Uref is the experimental reference location). Similarly, u'v'/(Uinf²) turbulence values from CFD need to be divided by approximately 0.93². However, the surface pressure coefficients from CFD agree better with the experiment on the airfoil lower surface when no such correction is made (the matching of the lower surface Cp is often used as a way to determine whether or not the flow conditions are consistent). The reason for this inconsistency is not known. Therefore, all comparisons for this case should only be viewed in a qualitative sense. Neither the surface pressure coefficients nor the surface skin friction coefficients from the CFD have been adjusted.

Note that this model is currently assigned MRR Level 2 for the purposes of this website. This is because at this time the TMBWG has results for this model from two different codes from the same home organization. The results on this page are therefore not necessarily reliable until additional independent code(s) can be used to verify the model implementation.

Jump to: SA Results,  SA-RC Results,  SSTm Results,  Wilcox2006-klim-m Results,  EASMko2003-S Results,  K-e-Rt Results,  GLVY-RSM-2012 Results

Return to: 2D NACA 4412 Airfoil Trailing Edge Separation Case Intro Page

Return to: Turbulence Modeling Resource Home Page

Recent significant updates:
12/17/2018 - added link to SA-RC results page
07/28/2016 - added plot of upper surface Cf as well as CDp and CDv values
03/27/2015 - updated plots to reflect proper y-offest in exp data

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Responsible NASA Official: Ethan Vogel
Page Curator: Clark Pederson
Last Updated: 03/17/2025