HEMLAB Algorithm Applied to 5th AIAA CFD High Lift Prediction Workshop

HEMLAB algorithm has been applied to the NASA High-Lift Common Research Model (CRM-HL) provided in Vth AIAA CFD High Lift Prediction Workshop in order to investigate mesh convergence behavior of aerodynamic loads as well as its pre-and post-stall characteristics at high angles of attack. The numerical method is based on a vertex based finite volume formulation on unstructured hybrid meshes and it has been integrated with INRIA pyAMG anisotropic mesh adaptation library to further improve its numerical accuracy. The numerical method can employ both linear (KSP) and nonlinear (SNES) iterative solvers for the monolithic solutions of the compressible Navier-Stokes equations with the one equation negative Spalart-Allmaras turbulence model using the restricted additive Schwarz preconditioner combined with the flexible generalized conjugate residual Krylov subspace algorithm within PETSc library. The initial calculations are carried out for the CRM-HL wing-body configuration in order to show aerodynamic loads dependence on mesh resolutions. Then the calculations are carried out with alpha continuation around the NASA High-Lift Common Research Model at pre-and post-stall angles of attack. The strong nonlinear PETSc SNES solver with alpha continuation has provided more consistent numerical results at high angles of attack which are in relatively good agreement with the workshop experimental data. The anisotropic mesh refinement is also found out to be very effective for resolving boundary layer, wakes, etc. while improving the numerical accuracy.