Environmental Engineering Reference
In-Depth Information
Table 5.1.
Classification parameter used in bed form theories.
Author
Classification parameter
Liu (1957)
u
∗
/
w
s
and
u
∗
d
50
/v
Simons & Richardson (1966)
τ
∗
v
and
d
50
Bogardi (1974)
gd
50
/
u
2
∗
van Rijn (1993)
T
and
D
∗
Bed form clasification
Liu (1957)
Accuracy 53%
Bed form clasification
Simons-Richarson (1966)
Accuracy 77%
100
100
No motion
Flat bed
Ripples
Dunes
No motion
boundary
10
Ripples
Dunes
10
Dunes
No motion
boundary
Ripples
1
No motion
1
Ripples
boundary
Dunes
boundary
Ripples
boundary
Dunes
boundary
0.1
0.1
0.01
1
10
0.0
0.10
0.20
0.30
0.40
0.50
0.10
U
x
d
50
/Ã
Median diameter d
50
(mm)
Bed form clasification
Bogardi (1974)
Accuracy 49%
Bed form clasification
van Rijn (1984)
Accuracy 82%
100
15
No motion
Smooth bed
Ripples
10
10
Ripples
Dunes
Smooth
boundary
Ripples
Dunes
Dunes
Mega-ripples
Dunes
1
5
Ripples
boundary
Dunes
boundary
Transition
Ripples
0.1
0
0.01
0.01
0
5
10
15
Median diameter d
50
(cm)
Particle parameter D
*
Figure 5.5.
Comparison of theories for predicting bed forms for lower flow regimes.
In order to find an appropriate theory to describe and predict the type
of bed forms in irrigation canals the theories developed by Liu (1957),
Simons and Richardsons (1966), Bogardi (1974) and van Rijn (1984c)
have been compared on the basis of field and laboratory data (Figure 5.5).
These theories explain the bed forms for one-directional flows and for
homogeneous conditions, both in time and space (Jansen, 1994). Brownlie
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