FM-1849-42 Open-Channel Sediment Transport

Experiments

  • Bed-load transport in open channels.
    • sub-critical and super-critical flow
    • formation of ripples, dunes and antidunes
  • How flow velocity affects bed-load transport.
  • Fluvial obstacle mark (siltation/scour formation)
    • bridge pier
    • sluice gate
  • Bed-load transport formulae
    • Meyer-Peter and Müller formula
    • Einstein’s formula
    • determining the transport rate
  • Visualization of the flow
  • Open-channel flow without sediment transport
    • sub-critical and super-critical flow
    • control structure: sluice gate
    • discharge measurement on the sharp-crested Weir

Specification

  • Investigation of open-channel flow with and without bed-load transport.
  • Experimental flume, consisting of experimental section, inlet element, water outlet and closed water circuit.
  • Smoothly adjustable inclination of the experimental section.
  • Side walls of the experimental section are made of tempered glass for excellent observation of the experiments
  • All surfaces in contact with water are made of corrosion-resistant materials.
  • Flow-optimized inlet element for low-turbulence entry to the experimental section; inlet element with sediment trap to prevent sediment flowing back.
  • Closed water circuit with water tank with sediment trap for coarse sand, pump and manual flow rate adjustment.
  • Sluice gate and bridge pier for experiments with and without sediment transport.
  • Visualization of the flow using a contrast medium.
  • Discharge measurement via measuring weir in the water drain.
  • Level gauge for measuring the discharge depth and the height of the sediment surface.

Description

FM-1849-42 uses sand as an example to demonstrate important phenomena of bed-load transport in the area near the bottom. Open channel flow without sediment transport is also possible. Discharge can be sub-critical or supercritical.

The core element of the FM-1849-42 experimental flume with closed water circuit is the inclining experimental section. The side walls of the experimental section are made of tempered glass, which allows excellent observation of the experiments. All components that come into contact with water are made of corrosion-resistant materials (stainless steel, glass reinforced plastic). The inlet element is designed so that the flow enters the experimental section with very little turbulence and no sediment can flow back. The tank after the water outlet contains a sediment trap for coarse sand.

The inclination of the experimental flume can be finely adjusted to produce slope and to create a uniform flow at a constant discharge depth.

In addition to bed-load transport in open channels, some models can also be used to observe fluvial obstacle marks, namely scour formation and siltation at structures. A rounded-nosed pier or a sluice gate can be inserted into the experimental section.

The discharge is measured via a measuring weir in the water outlet and a level gauge. The level gauge is also used for profile measurement in the sediment and to determine the discharge depth at each point of the experimental section. A contrast medium can be injected to visualise the flow conditions.