DESCRIPTION

Technical Description

In many real open channels there is sediment transport that affects the flow behaviour. Normally the key component is bed-load transport. HM 166 uses sand to demonstrate important phenomena of bed-load transport in the area near the bottom. The transparent experimental section allows observation of the formation of ripples in the river bed.

HM 166 consists of a circulating, oval, transparent flow channel. A deepening for holding the sediment in the longitudinal side of the channel forms the experimental section. The other longitudinal side contains a paddle that produces the flow. A flow straightener at the inlet to the experimental section ensures low-turbulence flow. 

The speed of the paddle can be adjusted in order to study how the flow velocity affects the bed-load transport. Flow velocities can be generated in the region of critical discharge (without sediment). The paddle is driven by an electric motor and a belt drive. Motor and speed adjustment are located under the base plate and are water resistant. 

The fluvial obstacle mark, i.e. scour formation and siltation at bridge piers, is observed at three different pier models, which are inserted into the experimental section.

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

Learning Objectives / Experiments

Observation of

  * starting conditions for bed-load transport
  * how flow velocity affects bed-load transport
  * ripple and dune formation on the river bed
  * fluvial obstacle mark of bridge piers (scour formation and siltation)
  * secondary flows in channel bends

Additionally with fine sand
- observation of solid matter flows
- how sediment size and density affect sediment transport