 Von Kármán constant

The dimensionless coefficient in the logarithmic wall law and its mixing-length form $\ell =\kappa z$. Its numerical value is determined from the turbulence closure and measurements, rather than from dimensional analysis alone.

The von Kármán constant, denoted by \( k \), is a constant used in the field of fluid mechanics, particularly in the study of boundary layers and turbulence. It is a dimensionless quantity that arises in the logarithmic law of the wall, which describes the velocity profile of turbulent flow in the boundary layer adjacent to a surface.