Environmental Engineering Reference
In-Depth Information
F
g
=
grain Froude number (dimensionless)
F
g
cr
=
critical grain Froude number (dimensionless)
τ
∗
o
=
critical shear stress
σ
s
=
geometric standard deviation
S
=
bottom slope (dimensionless)
d
50
=
median diameter (mm)
R
g
=
grain Reynolds number (dimensionless)
R
=
hydraulic radius (m)
kinematic viscosity (m
2
/s)
ν
=
A.4 ENGELUND AND HANSEN METHOD
The method of Engelund and Hansen (1967) is based on energy consider-
ations and a relationship between the transport and mobility parameters.
The total sediment transport is calculated by:
- Transport parameter
φ
q
s
φ
=
(
s
(A.15)
1)
gd
50
−
- Mobility parameter
θ
u
2
∗
θ
=
(A.16)
(
s
−
1)
gd
50
The relationship between the parameters is expressed by:
0
.
1
θ
2
.
5
C
2
2
g
φ
=
(A.17)
The total sediment transport is expressed by:
0
.
05
V
5
q
s
=
(A.18)
(
s
−
1)
2
g
0
.
5
d
50
C
3
where:
q
s
=
total sediment transport (m
3
/s.m)
θ
=
mobility parameter
φ
=
transport parameter
V
=
mean velocity (m/s)
C
=
de Chézy coefficient (m
1
/
2
/s)
u
∗
=
shear velocity (m/s)
d
50
=
mean diameter (m)
The Engelund and Hansen function for the total sediment transport has
been evaluated with laboratory data that were characterized by graded
sediment (
σ
s
<
1.6) with median diameters
d
50
of 0.19 mm, 0.27 mm,
0.45 mm and 0.93 mm. The method is not recommend for the cases,
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