Darcy friction factor f as a function of Reynolds number Re and pipe relative roughness ε / d, fitting the data of experimental studies of turbulent flow in smooth and rough pipes. The equation can be used to (alliteratively) solve for the Darcy–Weisbach friction factor f. For a conduit flowing completely full of fluid at Reynolds numbers greater than 4000, it is expressed as: 1/√(f) = -2*log((e / d) / 3.7 + 2.51/(Nre * √(f)) As can see from the formula, simple calculation is not possible, so user should use iterative calculations or a solver to find the value of f that satisfies the formula. Pipe Material Commercial Steel, e = 0.05
Pipe Internal Diameter (d, mm) = 25
Reynold's Number (Re) = 100000
Relative Roughness (ε/D) 0.002
Friction factor (f) 0.023
import math
import numpy as np def frictionfactor(piping, d, Nre):
piping = "Commercial Steel"
if piping == "Commercial Steel": e = 0.05
if piping == "Cast Iron": e = 0.26
if piping == "Galvanized Iron": e = 0.15
if piping == "Asphalted Cast Iron": e = 0.12
if piping == "Drawn Tubing": e = 0.0015
if (Nre > 1 and Nre <= 2000):
f_result = 64 / Nre
elif Nre > 4000:
delta_result = 1
delta = 1
for f in np.arange(0.001, 0.1, 0.001):
lhs = 1 / math.sqrt(f)
rhs = -2 * math.log10((e / d) / 3.7 + 2.51 / (Nre * math.sqrt(f)))
delta = abs(lhs - rhs)
if (delta < delta_result):
delta_result = delta
f_result = f
else:
pass
return f_result
f = frictionfactor("Commercial Steel", 25, 10000)
print("darcy friction factor = ", f)When run the code, you will receive the following results. darcy friction factor = 0.034
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