Boundary layer physics
The 100th anniversary of a complex nonlinear system's theory

Siegfried Grossmann
Universität Marburg

On 12 August 1904 Ludwig Prandtl gave a talk on high Reynolds number (or small viscosity) fluid flow, which soon proved to be a breakthrough in our understanding of the fundamental and ubiquitous role of viscosity for all flows. In his seminal contribution he detected the boundary layer and its importance, described its basic features, in particular its scaling with (Re)-0,5, the phenomenon of boundary layer separation and how it causes drag and lift forces.
This colloquium talk is devoted to our present view of boundary layer physics and some of its consequences and riddles.