Later stages of transition of an airfoil boundary layer flow excited by a harmonic point source

Abstract

Laminar-turbulent transition induced by a harmonic point source disturbance is investigated in a flat-plate boundary layer with adverse pressure gradient using Direct Numerical Simulation based on the complete three-dimensional Navier—Stokes equations for incompressible flow. Thus Tollmien—Schlichting waves of a single frequency and a large number of obliqueness angles are stimulated and propagate downstream simultaneously, undergoing amplification by primary and subsequent instability, and eventually lead to breakdown of the laminar flow. The attention of this work is directed to the non-linear stages and final breakdown of the disturbed laminar flow.