Explicit presentation of the Colebrook's friction factor equation

Abstract

Two explicit and very accurate equations for calculating the friction factor of pipes over the entire range of relative roughness and Reynold's Number covered by the Colebrook's Equation have been developed. A rectangular array of relative Roughness and Reynold's Number was used to test the accuracy of the new equation. The first equation had over 85% of the data points exactly (up to 5 decimal places) as the Colebrook's values. Errors in the remaining table values range between +-0.0555%. The second equation, which is an extension of the first equation, simply duplicates Colebrook's iterative solution.

Journal of the Nigerian Association of Mathematical Physics Vol. 9 2005: pp. 325-330