On the Karman constant

摘要: Numerous studies in the past 40 years have established that turbulent flow fields are populated by transient coherent structures represent patches of fluids moving cohesively for significant distances before they worn out momentum exchange with surrounding fluid. Two particular well-documented hairpin vortices move longitudinally above wall and ejections inclined respect to bring fluid from viscous layers underneath these into outer region boundary layer. It is proposed Karman universal constant logarithmic law sine angle between direction normal wall. The edge buffer layer represented a combination damping function Computation this experimental data velocity distributions shear flows matches published traces fronts turbulence obtained time shifts peak correlation velocity. Key works: Turbulence, structures, constant, mixing-length,