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Wave Gauges

The one wire type wave gauges used in the Large Wave Channel (GWK) of the Coastal Research Centre are based on a combined "resistance-capacity" technique. Each of the wave gauges consists of two electrodes, a measuring wire and the ground plane. In the GWK the electrical ground is formed by the mechanical supporting frame using aluminium pipes (see photo).

The minimum length is restricted by the required minimum electrical resistance of the measuring wire of about 5 Ohms. Length less than two meters will become critically. The maximum length is only limited by practical mechanical reasons. The wave gauge can also be used for instance as an up-rush gauge on a dike or breakwater. 

The measuring principle substantially based on measuring the voltage drop which is proportional to the depth of immersion of the wire. To avoid aberrations from the length of the cable between the measuring site and the data acquisition unit for each wave gauge a water sealed pre-amplifier is used which has to be installed near the wire. Up to six gauges are supported by a central processing with power supply, amplifier insertion, and pre-amplifier. The maximum distance between the central unit and each of the pre-amplifiers can be up to 100 m.

The gauges work with different carrier frequencies. That makes it possible to install two or more of them parallel close side by side.

 

Type / Model

Wave Gauges                                  

Measured variable

Surface elevation in [mm]

Accuracy of measurement

± 10 mm

Accuracy of wave height (ηmax – ηmin)

± 5 mm

Sampling rate range

up to 50 kHz (internal working frequency is between 4 kHz and 6 kHz)

Output

Analogue output, amplification about 1.3 Volts/m

Dimensions

Wires: max. length 4.5m, Ø 1mm

Other

 

Further Information