What turbulence models are commonly used in aerospace CFD and when?

Common turbulence models include: Spalart-Allmaras (SA) - one-equation model, good for attached flows and aerospace applications; k-omega SST - two-equation model combining k-epsilon freestream behavior with k-omega near-wall accuracy, good for separation; Reynolds Stress Models (RSM) - full anisotropic stress modeling for complex flows; and Large Eddy Simulation (LES) - resolves large eddies, models small scales, for unsteady phenomena. Model selection depends on flow physics, accuracy requirements, and computational cost. SA and SST handle most aerospace RANS applications, while LES/DES is used for buffet, noise, and separated flows.