Free surface flow rate measurements are found using a combination of level measurements, speed measurements and channel shape. The flow rate is therefore obtained by combining the flow rates in each part of the wetted section.
A measuring point consists of:
- 1 converter,
- 1-2 level sensors,
- 1-8 speed measurement chords.
The amount and position of the probes depends on:
- the height of the structure,
- the tide range,
- the specific features upstream and downstream of the site in question,
- the required precision.
Ultrasound measurements present several advantages for this type of application:
- reliable process unaffected by the nature of the fluid and its temperature,
- highly dynamic measurements: good results at both low and high water levels,
- takes into account different velocity profiles (up to 8 chords),
- takes into account the entire section of the structure,
- defines the section precisely using 20 points incorporating left and right width/height,
- can be used to take measurements in very wide structures (200 m).
This measurement principle can also be applied to partially filled pipes.
Discover our flow meters for channels and rivers.