Eddy kinematic viscosity, isotropic turbulence

Eddy kinematic viscosity, isotropic turbulence 702 penetration of laminar sub-layer 701... 

The importance of the universal velocity profile is discussed in Section 12.4. From equation 12.18, for isotropic turbulence, the eddy kinematic viscosity, EaXEuE where XE is the mixing length and uE is some measure of the linear velocity of the fluid in the eddies. The momentum transfer rate per unit area in a direction perpendicular to the surface at position y is then ... 

The principal feature of turbulent flows is the presence of eddies which are large compared with the molecular scale and which aid the mixing process (turbulent dispersion). This mixing mechanism in liquids is often rapid compared with the other processes of bulk flow and molecular diffusion. The eddies vary in size, having a maximum scale, L, which is of the order of the scale of the equipment (i.e. impeller or baffles) down to a minimum value, /, which, according to Kolmogoroff, for isotropic turbulence depends only upon the power input per unit mass to the system and the kinematic viscosity of the liquid ... 

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