Three explicit equations to compute the "f coefficient of the head loss universal equation have been compared with the Colebrook-White implicit equation. The equation obtained by the substitution of the second term (<img border=0 width=27 height=21 src="../../../../../../img/revistas/cr/v22n2/a06img01.gif">) of the log argument in the Colebrook-White equation, by the Konakov approximation (NEKRASOV, 1968) was the one which showed the best fit (r² = 0.9996), when the results from the three explicit equations were correlated to the values given by the Colebrook-White equation. The maximum relative error was approximately 2.72 % .
head loss; "f" Coefficient; explicit equations
