Sediment Investigation at the 30 Water Intake - Experimental Methods in Hydraulic Research - page 211

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1

Bulle
Hasanpour
Barkodoll
Shafai
This paper

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0.6

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0 0.1 0.2 0.3 0.4 0.5 0.6

Qr

Fig. 6 Comparison between the results of this study and other

are compared with those of Barkdoll et al. ( 1999 ), Shafai Bajestan and Nazari
( 1999 ), Bulle (quoting from Schoklitsch 1937 ), and Hasanpour 2006 ). Of course, it
is not so likely that the tests in different lab conditions be similar; however, by
considering the process of changes, one can predict the effect of the wall slope as
well as the suspended load. The main reason of the difference in the increase pattern
of the infiltrating sediments along the increase of diversion flow ratio is the
performance of the experiments with different Froude numbers under diverse
geometric conditions of the main and branch channels.
In Hasanpour's ( 2006 ) work, an almost linear relation between the diversion
flow ratio and the suspended load can be seen. There exists a turning point in
Barkdoll's ( 1999 ) results from where on, any increase in the diversion flow ratio
leads to a decrease in the infiltrating load ratio. The researches of Shafai and Nazari
were done in a 90 bend intake with 60 intake angle, which causes much less
sediment entry compared to other studies. Bulle made his experiments in 30 intake
installed on a rectangular channel. Since in this study the tests are also performed
with the same angle at a 25-cm depth with the most suspended load ratio, our results
are in harmony with Bulle's.
A comparison makes it clear that with a constant infiltrating sediment ratio, the
diversion flow ratio in this research is greater than that of Bulle, so G r / Q r ratio is less
than in Bulle's research, which shows that slopping the channel wall has a positive
role in the decrease of the suspended load infiltration. The infiltrating sediment ratio
for depths of 10 and 20 cm is less than that for 25-cm depth; hence, the ratio G r / Q r at
these two depths is surely smaller than Bulle's. The relation between G r / Q r and the
Froude number at the upstream is presented in Fig. 7 . It can be noticed that as the
Froude number grows, in all the three depths we have a decline in the rate of
infiltrating sediments to the intake, but in the bounded interval of Froude number
0.35-0.40 this rate reaches its minimum, and after these bounds it shows a relative