Friction Factor f

This file provides an analytical expression for the Moody Diagram friction factor, f, as a function of Reynolds Number and pipe relative roughness (e/D). This is very handy for fluid flow analysis problems, to replace the drudgery of looking up f from the graphical Moody Diagram, depending on the Reynolds Number.

The file gives examples of determining the Reynolds Number for water flowing in a pipe and then using Churchill's 1977 relationship for f based on Reynolds Number and relative roughness of the pipe. A copy of the original paper is embedded in the Excel file. The empirical formula is fully disclosed for transparency.