Fanning friction factor, turbulence parameters

Turbulent flow of Newtonian fluids is described in terms of the Fanning friction factor, which is correlated against the Reynolds number with the relative roughness of the pipe wall as a parameter. The same approach is adopted for non-Newtonian flow but the generalized Reynolds number is used. 

Use of friction factor for friction loss in laminar flow. A common parameter used in laminar and especially in turbulent flow is the Fanning friction factor, f which is defined as the drag force per wetted surface unit area (shear stressr, at the surface) divided by the product of density times velocity head or pu. The force isApy times the cross-sectional area t R and the wetted surface area is 2nR AL. Hence, the relation between the pressure drop due to friction and/is as follows for laminar and turbulent flow. 

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