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Description of the experimental setup
For the preliminary tests, an assembly of small pipes (6) calmed the inflowing water (see §4.1.3).
Due to the significant head losses caused by these pipes, they were replaced by a floating polystyrene
plate in the main test series to obtain better flow conditions.
The sediment supply (1), described in detail in paragraph 4.1.2, allowed to store half a cubic meter
of sediments in a conic tank. On the bottom of the reservoir, a rotating cylinder with a longitudinal
slide controlled the sediment rate. The sediments were transported by two conveyor belts (2
and 3) into the channel where they were distributed by an inclined plate (see Fig. 4.2).
Figure 4.2: Sediment inlet (left) and sediment sampling at the outlet (center and right)
At the outlet, a restitution basin collected the water and the sediments. The basin was equipped
with a tilting gate (10) which allowed to control the water level at the outlet. The tilting gate was
only used during filling and emptying of the channel to avoid bed erosion. During the tests, the
gate was lowered. The flow conditions on the exit overfall were critical. A sediment sampling
device (11) was located in the restitution basin (see Fig. 4.2 center and right). Two outlet pipes (12)
collected the water and the sediments and lead them to an easily interchangeable filtering basket
(13) which retained the sediments. The water was collected in the general basin (800 m 3 ) of the
Hydraulics Laboratory and recirculated in the experimental channel.
5
6
4
3
2
1
3
1. Inlet
2. Perforated tube
3. Assembly of small pipes (pipe grid)
4. Entry reach (7.5 m)
5. Bend (R center = 6 m, opening = 90°)
6. Exit reach (6 m)
Figure 4.3: Testing facility during construction
EPFL Ph.D thesis 2632 - Daniel S. Hersberger November 9, 2002 / page 69