Environmental Engineering Reference
In-Depth Information
where:
q
b
=
bed load transport (m
2
/s)
u
b
=
particle velocity (m/s)
c
b
=
bed load concentration
c
o
=
maximum volumetric concentration
=
0.65
T
=
bed shear parameter
D
∗
=
particle parameter
u
∗
=
bed shear velocity related to grains (m/s)
C
=
de Chézy coefficient related to grains (m
1
/
2
/s)
C
=
18 log(12
h
/3
d
90
)
δ
b
=
saltation height (m)
d
50
=
median diameter (m)
The suspended load transport
The suspended sediment transport
q
sus
, is the depth integrated product
of the local concentration and the flow velocity. The method of van Rijn
(1984b) is based on the computation of the reference concentration from
the bed load transport.
The field and laboratory data came from tests with the following
characteristics:
- mean velocity
=
0.4-2.4 m/s
- flow depth
=
0.1-17 m
- median diameter
=
0.1-0.4 mm
The suspended load transport follows from:
q
sus
=
FVhc
a
(A.27)
- shape factor
F
:
(
a/h
)
Z
(
a/h
)
1
.
2
−
F
=
(A.28)
a/h
)
Z
(1
.
2
(1
−
−
Z
)
- suspension parameter
Z
w
s
βκu
∗
Z
=
(A.29)
2
w
s
u
∗
2
β
=
1
+
(A.30)
- modified suspension parameter
Z
Z
=
Z
+
ψ
(A.31)
2
.
5
w
s
u
∗
0
.
8
c
a
c
o
0
.
4
ψ
=
(A.32)
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