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Dynamically Rough Boundary Scattering Effect on a Propagating Continuous Acoustical Wave in a Circular Pipe with
Anna V Romanova1, Kirill V Horoshenkov2, Anton Krynkin3
1Faculty of Engineering & Science, University of Greenwich, Central Avenue, Chatham, Kent ME4 4TB, UK. a.romanova@gre.ac.uk.
Sensors (Basel, Switzerland)
|April 6, 2018
Summary
A new acoustic method non-invasively measures free surface roughness in turbulent pipe flow. This technique relates acoustic signals to flow depth and roughness, offering insights into hydraulic friction factors.
Area of Science:
- Fluid dynamics
- Acoustics
- Hydraulic engineering
Background:
- The free surface of turbulent flow in pipes is crucial for understanding hydraulic processes.
- Directly measuring free surface roughness and its temporal variations is challenging due to its dynamic and non-stationary nature.
Purpose of the Study:
- To introduce and validate a novel acoustic method for characterizing free surface roughness in partially filled circular pipes.
- To establish a non-invasive technique for assessing hydraulic conditions through acoustic measurements.
Main Methods:
- Utilizing a continuous sine wave transmitted through air above the turbulent water flow.
- Employing an instrumented pipe section with wave probes and microphones to record the acoustic field.
- Correlating acoustic data with standard deviation of free surface roughness and mean flow depth.
Main Results:
- Demonstrated a clear relationship between variations in the recorded acoustic field and free surface roughness.
- Showed that acoustic data correlates with mean flow depth across various flow regimes and pipe bed conditions.
- Established a link between airborne acoustic data and the hydraulic friction factor of the pipe.
Conclusions:
- The developed acoustic method provides a non-invasive means to study free surface roughness in turbulent pipe flow.
- Airborne acoustic measurements can be effectively used to infer key hydraulic parameters like friction factor.
- This technique offers a promising alternative for monitoring and understanding complex flow dynamics in pipes.
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