(Bug?) HP48 Equation Library

[Mark Hardman]

(02-12-2017 03:36 PM)Han Wrote:  The problem is that \( f \) is never defined anywhere. Instead, there is reference to an \( \epsilon \) (roughness) that is defined as a variable, but never used.

This is the FANNING function which calculates the Fanning friction factor (\(f\)).

From HP 82211A HP Solve Equation Library Application Card Owner's Manual, page 193:

Quote:The FANNING(\(\epsilon\)/D, Re) function calculates the Fanning friction factor \(f\),
a correction factor for the frictional effects of certain fluid flows (constant
temperature, cross-section, velocity, and viscosity-typical pipe flow).
\(\epsilon\)/D is the relative roughness - the ratio of the conduit roughness to its
diameter. Re is the Reynolds number (conduit diameter x average velocity
x fluid density / fluid viscosity). The function uses different computation
routines for laminar flow (Re <= 2100 and turbulent flow (Re > 2100.
\(\epsilon\)/D and Re must be real numbers or unit objects that reduce to
dimensionless numbers. \(\epsilon\)/D and Re must be greater than 0.

FANNING takes \(\epsilon\)/D from level 2 and Re from level 1, and it returns the
Fanning friction factor in level 1.