DESCRIPTION

Technical Description

HM 168 demonstrates important phenomena of bed-load transport in the area near the bottom at subcritical discharge. The large dimensions of the experimental section enable the modelling of river courses with and without structure.

The core element of the HM 168 experimental flume is the stainless steel experimental section. A sediment layer up to 10cm high covering an area of 5x0,8m allows bed-load transport to be studied. The sediment is held in the experimental section by plate weirs at the inlet and at the outlet. The tank after the water drain contains a sediment trap with a filter element for sand. The water circuit is closed.

In addition to bed-load transport in open channels without structures, some models can also be used to observe fluvial obstacle marks, namely scour formation and siltation at structures. A bridge pier, a plate weir or an island can be inserted into the experimental section. You can also design your own models using deflection plates and angular steel.

Profile measurement in the sediment along the bottom and the determination of the discharge depth at each point on the experimental section is done via a movable instrument carrier and a point gauge. The discharge is measured via an electromagnetic flow meter.

The well-structured instructional material sets out the fundamentals and provides a step-by-step guide through the experiments.

Learning Objectives / Experiments

- bed-load transport in open channels
- how flow velocity affects bed-load transport
- ripple formation on the river bed
- observing the formation of meanders
- fluvial obstacle marks on structures
  * bridge pier with rectangular profile
  * rounded-nosed bridge pier
  * pointed-nosed bridge pier
  * island (round or rectangular)
- bed-load transport formulae 
  * Meyer-Peter and Müller formula
  * Einstein's formula