Environmental Engineering Reference
In-Depth Information
- Particle mobility
F
fg
u
∗
gd
35
(
s
F
fg
=
(B.24)
−
1)
- Mobility parameter related to the effective shear stress
A
)
1
.
0
0
.
76
1
1
exp(log
D
∗
)
1
.
7
F
gr
=
(
F
fg
−
−
−
+
A
(B.25)
- Mean velocity:
F
gr
gd
35
(
s
1
/
(1
−
n
)
√
32 log
h
d
35
−
1)
V
=
(B.26)
u
n
∗
with:
n
=
1
−
0
.
56 log
D
∗
(B.27)
0
.
23
√
D
∗
+
A
=
0
.
14
(B.28)
- The de Chézy coefficient follows from:
g
0
.
5
V
u
∗
C
=
(B.29)
where:
D
∗
=
particle size
F
fg
=
particle mobility
F
gr
=
particle mobility related to the effective shear stress
d
35
=
particle size (m)
A
=
initial motion parameter
n
=
exponent in the mobility parameter related to the effective
shear stress
h
=
water depth (m)
gravity (m/s
2
)
g
=
u
∗
=
shear velocity (m/s)
V
=
mean velocity (m/s)
s
=
relative density
de Chézy coefficient (m
1
/
2
/s)
C
=
kinematic viscosity (m
2
/s)
ν
=
B.4 ENGELUND
Engelund (1966) defined the shear stress due to skin and form resis-
tance by:
τ
+
τ
τ
=
(B.30)
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