Comment on “Gene expression programming analysis of implicit Colebrook–White equation in turbulent flow friction factor calculation”

• Unknown friction factor, f, in the Colebrook's equation is given implicitly.
• Using an accurate solution method is essential to the parameter estimation.
• Two accurate explicit approximations for flow friction factor are obtained.
• The maximum relative error of new approximations are less than 0.022% and 0.008%.

Recently, it is investigated (Samadianfard, 2012) the potential of genetic programming based technique in estimating flow friction factor in comparison with the most currently available explicit alternatives to the Colebrook's equation.Using iterative solution of the Colebrook's equation which is accurate to six significant digits, this discussion showed that the proposed approximation by the author for friction factor is not very accurate (the errors increase up to 7.374%), thus it is proposed two new accurate approximations (with maximum error less than 0.022% and 0.008%) for estimating flow friction factor.

Figure optionsDownload as PowerPoint slide