Tollmien-Schlichting wave
a linear Tollmien-Schlichting wave (TS) in a boundary layer
(results from the linear stability theory )
The Tollmien-Schlichting wave (after Walter Tollmien and Hermann Schlichting ) is a term from fluid mechanics in connection with the linear stability theory .
A speed boundary layer forms between the surface and the outer flow on airfoils (or bodies around which air flows in general) . a. the frictional resistance causes the body. The boundary layer is initially laminar and has little resistance.
Very small disturbances with wave character (the Tollmien-Schlichting waves) are intensified with increasing distance in the boundary layer, they cause a transition to the turbulent boundary layer and thus a higher resistance. The frequency of these interfering waves depends on the fluid and the flow velocity ; in wind tunnel tests it is typically between 100 Hz and 1000 Hz.
Intensive work is being done around the world to relocate this laminar-turbulent transition - the transition to turbulence - on wings and tail units to greater wing depths in order to reduce their aerodynamic drag .