This work details ongoing efforts at the NASA Langley Research Center to develop and validate a general-use CFD tool that includes built-in predictions of boundary-layer transition in high-speed flows. Existing tools for the coupling of the NASA OVERFLOW structured overset RANS solver and LASTRAC stability analysis code have been extended to capture boundary-layer transition in high-speed flows driven by either Mack’s first-mode or secondmode instabilities and/or crossflow instabilities. The efficacy of this coupled approach has been demonstrated by examining a variety of supersonic and hypersonic test cases for which experimental validation data is available. The intermittency prescription parameters inherited from prior low-speed applications are found to be suitable for some, but not all high-speed flow scenarios. The method is found to be robust for straight cone configurations and improvements necessary to accurately capture transition on geometries with spatially complex amplification factor envelopes with intermediate regions of slow N-factor variation are examined. The automated, coupled analysis is demonstrated for a 3d supersonic test case and found to perform well within the limits of the linear stability analysis on which it relies. Finally, a preliminary investigation of the method’s robustness to non-ideal CFD meshes is conducted.
CFD Integrated Transition Modeling for High-Speed Flows via Coupled OVERFLOW-LASTRAC Analysis
AIAA SciTech Forum and Exposition ; 2023 ; National Harbor, MD, US
2023-01-19
Aufsatz (Konferenz)
Keine Angabe
Englisch
Transition modeling , Transition , Fluid Mechanics And Thermodynamics , Parabolized stability equations , Angle of attack , Laminar to turbulent transition , Freestream Mach Number , Computational fluid dynamics , Turbulence models , Reynolds Averaged Navier Stokes , NASA Langley Research Center , Linear stability theory , Stability and transition , Wall temperature , Heat transfer , High-speed flow , Axisymmetric flow