Assessment of numerical uncertainty around shocks and corners on blunt trailing-edge supercritical airfoils

Numerical uncertainties are quantified to guide grid refinement in calculations of subsonic and transonic flow around supercritical airfoils with blunt and divergent trailing edges. The concept of grid convergence index (GCI), which extrapolates error estimates from arbitrary grid refinement ratios to those equivalent to grid doubling, was used to assess the adequacy of grid refinement. Values of grid convergence indices were calculated from aerodynamic-force and surface-pressure coefficients that were calculated by solution of compressible Reynolds-averaged Navier-Stokes equations on several grids, with emphasis placed on the effect of the shock and the corners on accuracy. The strategies described for grid refinement calculated base pressure to within 2% GCI and shock location within 1%, of chord, and shows numerical factors are more significant to calculated values of aerodynamic drag than lift. (C) 2001 Elsevier Science Ltd. All rights reserved.