Noninvasive Acoustic Measurements in Cylindrical Shell Containers

Area of Science:

• Physics
• Materials Science
• Acoustics

Background:

• Acoustic time-of-flight (ToF) is vital for noninvasive material characterization, imaging, and defect detection in various industries.
• Guided waves in cylindrical structures interfere with ToF measurements of contained fluids, hindering accurate analysis.
• Existing methods struggle to isolate fluid wave propagation from shell wall guided waves.

Purpose of the Study:

• To develop and demonstrate a novel technique to overcome guided wave interference in acoustic ToF measurements.
• To enable accurate characterization of fluids within cylindrical conduits.
• To improve the reliability of noninvasive material analysis in industrial and biomedical applications.

Main Methods:

• Utilized broadband linear chirp excitation to leverage frequency-dependent wave dispersion.
• Employed cross-correlation detection to distinguish between fluid and guided wave signals.
• Validated the technique through experimental measurements and numerical simulations.

Main Results:

• The broadband chirp excitation effectively distorted guided waves due to dispersion, while preserving the bulk fluid wave signal.
• Demonstrated successful separation of fluid wave propagation from interfering guided waves.
• Characterized measurement performance, including error, signal-to-noise ratio, and resolution, as a function of chirp parameters.

Conclusions:

• The proposed technique effectively mitigates guided wave interference in acoustic ToF measurements of fluids in pipes.
• Broadband chirp excitation and cross-correlation offer a robust solution for accurate fluid characterization.
• The findings provide a pathway for optimizing noninvasive acoustic measurements in challenging environments.