Hall hydraulic

The hydraulic facilities of Irstea consist in a 350 m² laboratory in environmental hydraulics. It is part of the ECOUFLU network that aims at gathering and structuring the Rhône-Alps research institutions to improve knowledge of free-surface flow processes, especially natural flow in rivers or urban systems.

These facilities are:

  • A wide flume, 3 m-width, 18 m-long, 80 cm-deep, at the fixed slope of 1/1000.
  • A tilting flume, de  1 m-width, 18 m-long, 80 cm-deep, with a maximum slope of 5 %.
  • An urban model, in progress.

A non point  pollution flume, of 8 m-long,  0.4 m-width, to study plant protection products transfer in water and different substrate media.

The hydraulic facilities of Irstea consist in a 350 m² laboratory in environmental hydraulics. It is part of the ECOUFLU network that aims at gathering and structuring the Rhône-Alps research institutions to improve knowledge of free-surface flow processes, especially natural flow in rivers or urban systems.

These facilities are

  • A wide flume, 3 m-width, 18 m-long, 80 cm-deep, at the fixed slope of 1/1000.
  • A tilting flume, de  1 m-width, 18 m-long, 80 cm-deep, with a maximum slope of 5 %.
  • An urban model, in progress.

A non point  pollution flume, of 8 m-long,  0.4 m-width, to study plant protection products transfer in water and different substrate media.

The next figure presents the facilities implementation.

Water and sediment supply

The two long flumes (wide and tilting) are supplied in in three different ways:

  1. Clean water can be supplied through a constant head water tower. The water is then recycled in a basement area.
  2. Sediment (diameter < 1 mm) laden water can also be supplied in a close loop. The water is recycled in another smaller basement area equipped with stirrer to homogenize the sediment concentration.
  3. Finally, it is possible to work in an open configuration for coarse sediment. The sediment settles in an intermediate tank. The flumes are fed in sediment independently of the water.

The scheme below illustrated these different modes.

Moreover, these two flumes are entirely in glass so velocity measurements with PIV can be done the whole-length of the flume, from the sides or from the bottom.

Wide Flume

Projects

Among the different projects that use this flume are:

  • A PhD thesis of Victor Dupuis (2013-2015, supervised of S. Proust, C. Berni and A. Paquier, HHLY unit), on the effect of various flood plain roughness (grass, trees, …) to the compound channel flows. A compound channel will be set-up in the flume as specified on the following sketch.

  • Next experiments will study the flow around obstacles, and especially the interaction of several obstacles’ wakes. The large width of the channel will be an asset as uniform flow can be obtained in front of relatively large obstacles (around 10 cm).
  • Finally, this wide flume will be used to study sediment transport in complex morphology of flow such as meanders.

Technical specifications

Characteristics
Total length 18m
Width 3 m
Depth 80 cm
Up-stream 3 alimentations indépendantes
Maximum Discharge 300 L.s-1 (75 L.s-1  + 150 L.s-1  + 75 L.s-1)
Down-stream 3 tailgates

Instrumentation

Several sensors will be deployed:

  • Ultrasound sensors to measure free-surface elevation (9 sensors, 3 up-stream, 3 downstream, 3 mobile),
  • Discharge measurements with an electromagnetic flowmeter at the entrance of the flume.
  • Velocity measurements (Pitot tube, Acoustic Doppler Velocimeter, and PIV systems).

These sensors are fixed to a motorized trolley and can be moved automatically.
 

Tilting flume

Projects

This flume was mainly designed to study sediment transport. The study of the infiltration of fine sediments in a coarse subtract will be the first experiments in this flume.

Technical specifications