Delta Flume

The Delta Flume is a wave flume which is unique because of its dimensions. The flume has a length of 240 m, a width of 5 m and a depth of 7 m. A deepened section of 9.5 m is also available. A flume with these dimensions allows for physical models on a scale which is close to prototype. This means that there are hardly any scale effects to take into account. The state-of -the-art Delta Flume is capable of generating both regular (periodic) and irregular (random) waves. The wave generator is equipped with online Active Reflection Compensation, which effectively eliminates re-reflections of waves from the wave board. In this way they do not disturb the measurements. Also wave board control for random second-order waves is operational to compensate for spurious waves.

Application areas

Because of the size of the Delta Flume there is a wide range of applications in which we are involved.
Several breakwaters have been tested in the Delta flume. The stability of the armour layer and the overtopping discharge are typical measurements in such tests. Typical measurements carried out in the Delta Flume include wave height, pressures, flow velocities, overtopping volumes and profiles.
Tests related to erosion of sediments are difficult to investigate on a smaller scale. Problems regarding grain size are difficult to solve in a small scale model. The Delta Flume makes it possible to solve some of those problems because for instance the grain size can be one that is really found in nature.
The Delta Flume is a versatile and indispensable facility which can be put to use in numerous projects.

Projects

The size and available wave conditions of the Delta Flume make it possible to test almost every structure on a near-to-prototype scale. A few example projects are:

• Breakwaters
• Scour, bed protection
• Placed block revetments
• Testing underwater vehicles in combination with turbulent conditions
• Testing and calibrating field equipment

Technical specifications:

• Wave flume
  Length: 240 m
  Width: 5 m
  Depth: 7 m
  
• Wave generator
  Full stroke: 5 m
  Piston type (translatory) wave board
  Second-order wave steering system
  Active re-reflection compensation
  Installed electric power for wave generation: 800 kW
  
• Wave characteristics
  Maximum height (regular): 2.5 m
  Maximum sig.  height (random) (Hs): 1.6 m
  Wave period: 1 - 12 s
  
• Features
  Depth of deeper sections: 9.5 m
  Wave-damping structures
  Flexible water circulation system to fill or empty separate sections of the flume

Special equipment

Because the model dimensions are almost equal to prototype dimensions, the models have to be constructed by using specialized equipment. A wide variety of special equipment is available on the Delta flume, including a large gantry crane. With this equipment it is for example possible to construct a model with a foreshore (both mobile and fixed) over the flume bottom.
Special equipment is also required for the measurements. This equipment is available on the Delta flume. Some 100 channels with instruments can be sampled in the standard configuration. If necessary more channels can be added.