is the friction velocity which depends on the shear stress τw at the boundary of the flow: with ρ the fluid density.
The Kármán constant is often used in turbulence modeling, for instance in boundary-layer meteorology to calculate fluxes of momentum, heat and moisture from the atmosphere to the land surface.
Gaudio, Miglio and Dey argued that the Kármán constant is however nonuniversal in flows over mobile sediment beds.
In recent years the von Kármán constant has been subject to periodic scrutiny.
For incompressible and frictionless ("ideal") fluids, Baumert (2013) used Kolmogorov's classical ideas on turbulence to derive ideal values of a number of relevant constants of turbulent motions, among them von Kármán's constant as