Abstract
Local similarity laws such as log-law and velocity defect law in wall turbulence are discussed from the point of view of Experimental Fluid Dynamics (EFD). Emphasis is located on numerical constants involved in the similarity laws, that is, Karman constant which value is indeed important in engineering applications. It is decided that only experiments can give last for the issue. Approach to the similarity law with observation of large-scale eddies is demonstrated by utilizing transport equation for two-point correlation function.
