Boundary Shear Stress in Turbulent Boundary Layers on Smooth Boundaries

It is well known that in the case of turbulent flow over smooth boundaries, the velocity distribution in the neigh- i bourhood of the wall is given by the law of the wall, c written as whereuis the turbulent mean velocity at a normal distance of y from the boundary,u*is the shear velocity equal to being the boundary shear stress andρthe mass density of the fluid andvis the coefficient of kinematic viscosity. In the viscous sublayer, eqn. (1) becomes and in the turbulent flow region above the sublayer and the transition region, foryu*/v> 30, eqn. (1) becomes whereAandBare coefficients.