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Chapter 3 - Theoretical considerations
PETER slightly overestimates the scour compared to the lab tests of the present study. Since Peter
neglects the grain size, the overestimation may be due to the coarser grain size.
In order to obtain a better fit between computed and measured values (see Fig. 3.12), the computed
maximum scour depth can be adjusted with a correction factor F C . To estimate the quality
of the different scour formulae the regression coefficient is also given in Table 3.7.
Scour formula
R 2
Fargue 0.95 0.41
van Bendegom
Engelund
Bridge
Kikkawa et al.
Reindl
2.3
1.4
1.0
1.45
0.67*
0.79
0.54
0.29
0.32
0.21
Zimmermann
Falcon & Kennedy
Odgaard
2.4
1.9
1.8
0.79
0.75
0.73
Peter (rectangular)
(trapezoidal X-section) # 0.85
0.60
0.87
0.85
Table 3.7: Correction factors for scour formulae and correlations with lab experiments
* compared only to our tests (LCH), # compared to rectangular X-section data
F C R 2 F C
Figure 3.13 compares the maximum scour depth 1 , computed with the correction factors
Table 3.7 to the measured ones.
of
1. definition sketch of on Fig. 3.6 on page 40
h s
page 64 / November 9, 2002
Wall roughness effects on flow and scouring