Verification and Validation of RANS Turbulence Models in Commercial Flow Solvers
50th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition
The Spalart-Allmaras (S-A) turbulence model in NASA-Langley's CFL3D and FUN3D flow solvers has been previously verified 2 nd -order accurate, and for 3 unit-level 2-D, low subsonic applications (turbulent flat plate, planar jet, and NACA 0012 airfoil at α=0°), solutions from the S-A, S-A with Rotation and Curvature corrections (SARC), Menter Shear-Stress Transport (SST) and Wilcox 1998 k-ω turbulence models in commercial flow solvers, Cobalt and RavenCFD, are compared with the NASA results for
... e NASA results for code verification. All case evaluations are conducted using 5 systematically refined computational meshes. Of the 80 total case evaluations, only 7 clearly demonstrate solutions that approach 2 nd -order observed accuracy but 41 cases show 1 st -order or better, indicating the formal order may be less than 2 for these applications. Since Cobalt and RavenCFD turbulence models perform comparable to or better than NASA's verified models and since rigorous code verification with an exact solution is not possible without access to source code, the presented evidence suggests these turbulence models are implemented correctly for these or similar flow conditions and configurations. Estimates of uncertainty due to numerical error are included (all cases less than 1.7%), and some turbulence model validation is provided by comparing computational results with experiment. Specifically, the S-A and SARC turbulence models show excellent agreement with experiment for velocity profiles downstream of the 2-D jet in the planar shear case; for the NACA 0012 drag coefficient for α=0°, S-A and SST agree within 1.2% of experiment, SARC within 2%, and k-ω within 4%.