Effect of atmospheric turbulence on a laminar boundary-layer

Abstract

In connection with the loss of glide performance experienced by some sailplanes upon entering the turbulent air in thermals, we review experimental and theoretical investigations into the response of a laminar boundary layer to external (e.g. atmospheric) turbulence. Contrary to intuition, the excitation of Tollmien-Schlichting waves is such a feeble process that it is unlikely to play any significant role at all. The excitation of low frequency, high amplitude streaks, on the other hand, is a very efficient process that must be considered as a likely source of early laminar-turbulent transition within the boundary-layer.