Direct TS-wave simulation on a laminar wing-profile with forward-facing step

Abstract

Within the following computational study, Tollmien-Schlichting waves will be simulated behind a step on a laminar profile by direct numerical simulations. The airfoil geometry is designed as a reference-configuration for wind tunnel experiments. The character of the dominating transition mechanism by Tollmien-Schlichting waves allows a 2D approach. A well-validated high-order numerical scheme is chosen, which is adapted for detailed simulations of transitional modes. All simulations of the instabilities were carried out on the original airfoil-geometry by using an entirely resolved step-region. The central part of the airfoil in the open test-section of the DNW-NWB contains an adjustable inset to allow settings of different forward and backward-facing steps, comparable with high-resolution CFD-results. Efficient time-accurate simulations of the TS-mode growth were carried out on extracted CFD-grids of the critical region. Determining growth rates of these modes allow comparison with Linear Stability Theory (LST) and the prediction of the laminar-turbulent transition.