Introduction

  • 1
    Page: 1258: In friction factor relations 34, 35, 36, and 37, replace δ by D in first location, to read as
    34
    35
    36
    37
  • 2

    Page 1259: In Table 1, replace δ by D in the second column, and its corresponding term in the third column. Also in the third column of Eqs. (3a) and (3b), the numerical values 0.754 and 1.724 are replaced by 0.88 and 2.02, respectively. The corrected Table 1 is given below.

Table 1

Roughness scale and friction factors in fully rough and transitional rough pipes

ScaleFriction factor for fully rough pipesFriction factor for transitional rough pipes implicit and approximate explicit expressions; (j=11)1Eq.
Rq1λ=-2log10(Rq0.7D)1λ=-2log10[2.51Reλ+Rq0.7Dexp(-j1.062ReλδRq)](1a)
hs=5.333Rq1λ=-2log10[5.74Re0.9+Rq0.7Dexp(-j2.58Re0.9δRq)](1b)
RZ1λ=-2log10(RZ3D)1λ=-2log10[2.51Reλ+RZ3Dexp(-j4.55ReλδRZ)](2a)
hs=1.244RZ1λ=-2log10[5.74Re0.9+RZ3Dexp(-j10.41Re0.9δRZ)](2b)
Ra1λ=-2log10(Ra0.57D)1λ=-2log10[2.51Reλ+Ra0.57Dexp(-j0.88ReλδRa)](3a)
hs=6.45Ra1λ=-2log10[5.74Re0.9+Ra0.57Dexp(-j2.02Re0.9δRa)](3b)
Rq/H1λ=-2log10(Rq/H0.5D)1λ=-2log10[2.51Reλ+Rq/H0.5Dexp(-j0.754ReλδRq/H)](4a)
hs=7.71Rq/H1λ=-2log10[5.74Re0.9+Rq/H0.5Dexp(-j1.724Re0.9δRq/H)](4b)
h1λ=-2log10(h3.7D)1λ=-2log10[2.51Reλ+h3.7Dexp(-j5.66Reλδh)](5a)
1λ=-2log10[5.74Re0.9+h3.7Dexp(-j12.91Re0.9δh)](5b)
h1λ=-1.93log10(h3.7D)1λ=-1.93log10[2.51Reλ+h3.7Dexp(-j5.66Reλδh)](6a)
1λ=-1.93log10[4.22Re0.9+h3.7Dexp(-j9.50Re0.9δh)](6b)
ScaleFriction factor for fully rough pipesFriction factor for transitional rough pipes implicit and approximate explicit expressions; (j=11)1Eq.
Rq1λ=-2log10(Rq0.7D)1λ=-2log10[2.51Reλ+Rq0.7Dexp(-j1.062ReλδRq)](1a)
hs=5.333Rq1λ=-2log10[5.74Re0.9+Rq0.7Dexp(-j2.58Re0.9δRq)](1b)
RZ1λ=-2log10(RZ3D)1λ=-2log10[2.51Reλ+RZ3Dexp(-j4.55ReλδRZ)](2a)
hs=1.244RZ1λ=-2log10[5.74Re0.9+RZ3Dexp(-j10.41Re0.9δRZ)](2b)
Ra1λ=-2log10(Ra0.57D)1λ=-2log10[2.51Reλ+Ra0.57Dexp(-j0.88ReλδRa)](3a)
hs=6.45Ra1λ=-2log10[5.74Re0.9+Ra0.57Dexp(-j2.02Re0.9δRa)](3b)
Rq/H1λ=-2log10(Rq/H0.5D)1λ=-2log10[2.51Reλ+Rq/H0.5Dexp(-j0.754ReλδRq/H)](4a)
hs=7.71Rq/H1λ=-2log10[5.74Re0.9+Rq/H0.5Dexp(-j1.724Re0.9δRq/H)](4b)
h1λ=-2log10(h3.7D)1λ=-2log10[2.51Reλ+h3.7Dexp(-j5.66Reλδh)](5a)
1λ=-2log10[5.74Re0.9+h3.7Dexp(-j12.91Re0.9δh)](5b)
h1λ=-1.93log10(h3.7D)1λ=-1.93log10[2.51Reλ+h3.7Dexp(-j5.66Reλδh)](6a)
1λ=-1.93log10[4.22Re0.9+h3.7Dexp(-j9.50Re0.9δh)](6b)

Note: δ=a=D/2 = pipe radius or semi-depth of channel.

h = Equivalent sand grain roughness.

Rq = Root mean square (rms) roughness, RZ = Mean peak to valley heights roughness.

Ra = Arithmetic mean roughness, Rq/H = Height-Texture (HT) roughness.

a

Explicit approximate friction factor Eqs. (1b)–(5b) with A=2 based on approximate smooth pipe Eq. 38), and approximate explicit friction factor Eq. (6b) with A=1.93 based on Eq. (39).