Multi reflection of Lamb wave emission in an acoustic waveguide sensor

Area of Science:

• Physics
• Materials Science
• Sensor Technology

Background:

• Acoustic waveguide sensors utilize surface acoustic wave (SAW) mode conversion for liquid analysis.
• Applications include concentration measurement, liquid level sensing, and defect detection.
• Understanding wave propagation is crucial for sensor optimization.

Purpose of the Study:

• To visualize sound wave propagation within an acoustic waveguide sensor for the first time.
• To confirm multi-reflection phenomena predicted by theoretical models.
• To improve the interpretation and design of acoustic waveguide sensors.

Main Methods:

• Excitation of the antisymmetrical zero order Lamb wave mode using a 1 MHz transducer on 1 mm glass plates.
• Utilizing Schlieren imaging to visualize acoustic wave propagation.
• Investigating both continuous and burst operation modes.

Main Results:

• Schlieren imaging successfully visualized sound wave propagation and multi-reflection within the acoustic waveguide.
• The experimental visualization confirmed theoretical calculations based on receiver signals.
• Demonstrated the sensor's ability to detect wave interactions at solid-liquid interfaces.

Conclusions:

• Schlieren imaging provides direct evidence of multi-reflection in acoustic waveguide sensors.
• This visualization enhances the understanding of sensor mechanisms.
• The findings facilitate better sensor design and application development.