Integration of linear stability methods into Navier-Stokes solvers for computation of transonic laminar airfoils

Abstract

The coupling o f Navier-Stokes mean Aow calculations and linear stability analysis methods is examined. Several problems arising with this coupling are discussed, and a method for determination o f the laminar boundary layer edge in a Navier-Stokes solution from the local velocity profile is presented. Using a Aat plate boundarylayer, the accuracy o f the Navier-Stokesgenerated velocity profiles and their derivatives is investigated with emphasis on the influence o f artificial dissipation, mesh resolution and mesh stretching. A comparison is made between the N factors from direct stability analysis o f the Navier-Stokes solution and N factors from the exact Blasius solution. Finally, the integral boundary layer method o f Drela and Giles is implemented in a Na vier-Stokes solver to provide a transition location generated from the Na vier-Stokes pressure distribution