Tollmien–Schlichting wave

The Tollmien -Schlichting wave is a term used in fluid mechanics in the context of linear stability theory. They were named after Hermann Schlichting (1907-1982) and Walter Tollmien ( 1900-1968 ).

On wings (or in general of air flow around bodies ) forms between the surface and the outer flow velocity boundary layer, which causes, among other things the frictional resistance of the body. The boundary layer is initially laminar and low resistance. Very small perturbations with wave character ( the Tollmien - Schlichting waves) are amplified with increasing running distance in the boundary layer. They cause a transition to a turbulent boundary layer and thus a higher resistance. The frequency of said interference waves depends on the fluid and the flow velocity. In wind tunnel tests, it is typically between 100 Hz and 1000 Hz Worldwide is worked hard this laminar-turbulent transition - to relocate to wings and tail wings to larger depths to reduce the air resistance - the transition to turbulence.

• Turbulent flow