The standard expression for pipe friction calculations, the Colebrook equation, is in an implicit form. Here, we present two accurate approximate solutions, given by replacing the numerically unstable term in Keady's exact Lambert function solution with a truncated series expansion. The resulting expressions have a higher accuracy than most advanced approximations and a lower computational cost than basic engineering formulas. The simplest expression, given by retaining only three terms in the series expansion, has a maximum error of less than 0.153% for Re ≥ 4000. The slightly more involved expression, based on five terms, has a maximum error of 0.0061%.

References

1.
Colebrook
,
C. F.
,
1939
, “
Turbulent Flow in Pipes, With Particular Reference to the Transition Region Between the Smooth and Rough Pipe Laws
,”
J. Inst. Civ. Eng.
,
11
(
4
), pp.
133
156
.
2.
Moody
,
L. F.
,
1947
, “
An Approximate Formula for Pipe Friction Factors
,”
Trans. ASME
,
69
, pp.
1005
1006
.
3.
Brkić
,
D.
,
2011
, “
Review of Explicit Approximations to the Colebrook Relation for Flow Friction
,”
J. Pet. Sci. Eng.
,
77
(
1
), pp.
34
48
.
4.
Genić
,
S.
,
Arandjelović
,
I.
,
Kolendić
,
P.
,
Jarić
,
M.
,
Budimir
,
N.
, and
Genić
,
V.
,
2011
, “
A Review of Explicit Approximations of Colebrook's Equation
,”
FME Trans.
,
39
(
2
), pp.
67
71
.
5.
Lipovka
,
A. Y.
, and
Lipovka
,
Y. L.
,
2014
, “
Determining Hydraulic Friction Factor for Pipeline Systems
,”
J. Sib. Fed. Univ. Eng. Technol.
,
1
(
7
), pp.
62
82
.
6.
Churchill
,
S. W.
,
1973
, “
Empirical Expressions for the Shear Stress in Turbulent Flow in Commercial Pipe
,”
AIChE J.
,
19
(
2
), pp.
375
376
.
7.
Swamee
,
P. K.
, and
Jain
,
A. K.
,
1976
, “
Explicit Equations for Pipe-Flow Problems
,”
J. Hydraul. Div.
,
102
(
5
), pp.
657
664
.
8.
Håland
,
S. E.
,
1983
, “
Simple Explicit Formulas for the Friction Factor in Turbulent Pipe Flow
,”
ASME J. Fluids Eng.
,
105
(
1
), pp.
89
90
.
9.
Chen
,
N. H.
,
1979
, “
An Explicit Equation for Friction Factor in Pipes
,”
Ind. Eng. Chem. Fundam.
,
18
(
3
), pp.
296
297
.
10.
Barr
,
D. I. H.
,
1981
, “
Solutions of the Colebrook-White Function for Resistance to Uniform Turbulent Flow
,”
Proc. Inst. Civil. Eng.
,
71
(
2
), pp.
529
535
.
11.
Zigrang
,
D. J.
, and
Sylvester
,
N. D.
,
1982
, “
Explicit Approximations to the Solution of Colebrook's Friction Factor Equation
,”
AIChE J.
,
28
(
3
), pp.
514
515
.
12.
Serghides
,
T. K.
,
1984
, “
Estimate Friction Factor Accurately
,”
Chem. Eng. J.
,
91
(
5
), pp.
63
64
.
13.
Buzzelli
,
D.
,
2008
, “
Calculating Friction in One Step
,”
Mach. Des.
,
80
(
12
), p.
54
.
14.
Romeo
,
E.
,
Royo
,
C.
, and
Monzón
,
A.
,
2002
, “
Improved Explicit Equation for Estimation of the Friction Factor in Rough and Smooth Pipes
,”
Chem. Eng. J.
,
86
(
3
), pp.
369
374
.
15.
Keady
,
G.
,
1998
, “
Colebrook–White Formula for Pipe Flows
,”
J. Hydraul. Eng.
,
124
(
1
), pp.
96
97
.
16.
Sonnad
,
J. R.
, and
Goudar
,
C. T.
,
2007
, “
Explicit Reformulation of the Colebrook–White Equation for Turbulent Flow
,”
Ind. Eng. Chem. Res.
,
46
(
8
), pp.
2593
2600
.
17.
Clamond
,
D.
,
2009
, “
Efficient Resolution of the Colebrook Equation
,”
Ind. Eng. Chem. Res.
,
48
(
7
), pp.
3665
3671
.
18.
Mikata
,
Y.
, and
Walczak
,
W.
,
2015
, “
Exact Analytical Solutions of the Colebrook–White Equation
,”
J. Hydraul. Eng.
,
142
(
2
), p.
1061
.
19.
Sonnad
,
J. R.
, and
Goudar
,
C. T.
,
2004
, “
Constraints for Using Lambert W Function-Based Explicit Colebrook–White Equation
,”
J. Hydraul. Eng.
,
130
(
9
), pp.
929
931
.
20.
Lawrence
,
P. W.
,
Corless
,
R. M.
, and
Jeffrey
,
D. J.
,
2012
, “
Algorithm 917: Complex Double-Precision Evaluation of the Wright ω Function
,”
ACM Trans. Math. Software
,
38
(
3
), pp.
1
17
.
21.
Corless
,
R. M.
,
Gonnet
,
G. H.
,
Hare
,
D. E. G.
,
Jeffrey
,
D. J.
, and
Knuth
,
D. E.
,
1996
, “
On the Lambert W Function
,”
Adv. Comput. Math.
,
5
(
1
), pp.
329
359
.
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