Derivation of Swamee Jain equation

[brighton4]

Hey everyone, Im doing some work on valve flow coefficients and at the moment am writing a report of my research/calculations. I'm writing about the friction factor and was wondering where the Swamee Jain Equation comes from? is there a derivation of it, if so does anyone know where I can find it or what starting equations I can use to derive it?

Ft = 1/4 (log(e/3.7d)+(5.74/Re^0.9))^-2

Thanks

 

[cloa]

http://en.wikipedia.org/wiki/Darcy_friction_factor_formulae

 

[Latexman]

It comes from Swamee, P. K., and Jain, A. K. (1976). "Explicit equations for pipe-flow problems." J. Hydraulics Division, ASCE, 102(5), 657-664.

Good luck,
Latexman