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Chapter 4 - Experimental setup and test procedure
7
1000
450
312 .5
200 160 640 100
1150
1200
1000
0.072 m 3
1 0.121 m 3
1 0.291 m 3
1
180
0.011 m 3
2
50
3
4
5
6
364
Total 0.496 m 3
8
8
6
1. Sediment reservoir, 2. Rotating cylinder (with a slide opening), 3. Fuse to prevent rotating cylinder from damage,
4. Mechanic step-down gear, 5. Motor, 6. Electronic Frequency Modulator, 7. Gate to adjust the opening with thick
plastic lip, 8. Conveyor belt
Figure 4.6: Scheme of the used sediment supply
The sediment reservoir (1) had a storage volume of 0.50 m 3 . On its bottom, a rotating cylinder
with a slice opening (2) continuously pushed the sediments through a thick plastic lip to drop on
the conveyor belt (8). It was no problem to obtain high sediment rates. In order to get also low
transport rates, several speed reducing devices were mounted to the motor (5): a mechanic stepdown
gear (4) reduced the rotation rate by a factor 20 and an electronic frequency modulator (6)
allowed to reduce the initial rotation rate of the motor considerably. The axis was protected by a
mechanic fuse (3) from damage. A gate with a thick plastic lip (7) allowed the control of the opening
of the sediment supply (adjustment to the grain size and of the sediment supply rate). The precision
of the time-averaged sediment supply rate is estimated to be at about 10 to 15%.
page 72 / November 9, 2002
Wall roughness effects on flow and scouring