Question
Download Solution PDFThe mechanical device which is used to measure flow velocity, where the number of revolutions of the wheel per unit time are proportional to the velocity of the flowing water is the ____________.
Answer (Detailed Solution Below)
Detailed Solution
Download Solution PDFExplanation:
1) Current meter:
- The Pygmy Current Meter is a versatile instrument with a long history of accuracy, reliability, and durability.
- The precisely balanced Bucket Wheel mounts on a vertical pivot inside a yoke and rotates by water flow.
- Each rotation of the Bucket Wheel produces an audible click which users monitor either manually with a headset or with digital equipment.
- Rotation rate is proportional to water velocity
2) Acoustic doppler velocimeter:
- The acoustic Doppler velocimeter (ADV) is a new acoustic instrument with the potential to offer accuracy for laboratory devices even under field conditions.
- An acoustic Doppler velocimeter (ADV) operates by the principle of Doppler shift.
- The ADV uses this principle to measure the velocity of water in three dimensions. The device sends out a beam of acoustic waves at a fixed frequency from a transmitter probe.
3) Electromagnetic velocimeter:
- Electromagnetic current meters produce a voltage proportional to the velocity.
- One advantage of these current meters is the direct analog reading of velocity; counting of revolutions is not necessary.
- These current meters can also measure crossflow and are directional.
- Electromagnetic current meters, while still not as reliable as the anemometer type, have improved greatly in recent years. Their use of near metallic objects is still a limitation.
Last updated on May 28, 2025
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