Visualization of Acoustic Standing Waves in a Closed Pipe Based on an Electronic Speckle Pattern Interferometer

• Published in: Journal of the Korean Physical Society Vol. 77; no. 3; pp. 229 - 233
• Main Author: Park, Jeongwoo
• Format: Journal Article
• Language: English
• Published: Seoul The Korean Physical Society 01.08.2020; Springer Nature B.V; 한국물리학회
• Subjects: Acoustic waves; Acoustics; Irradiance; Mathematical analysis; Mathematical and Computational Physics; Nodes (standing waves); Particle and Nuclear Physics; Physics; Physics and Astronomy; Pipes; Speckle patterns; Standing waves; Theoretical; Wavelengths; 물리학; Visualization; Acoustic standing waves; Electronic speckle pattern interferometer
• ISSN: 0374-4884; 1976-8524
• DOI: 10.3938/jkps.77.229

We visualize acoustic standing waves supported in a closed-end square pipe based on an electronic speckle pattern interferometer and measure the wavelengths of the acoustic standing waves for undergraduate physics lab courses. Generating four acoustic standing waves of frequencies below the cutoff frequency governed by the physical dimensions of the pipe, we obtain the distribution of the irradiance difference of the speckle patterns in the interferogram and compare that to the result of a theoretical calculation. In addition, we estimate the wavelengths of the acoustic standing waves by measuring the distances between adjacent nodes of the speckle patterns. We show that the experimental results and the results of the theoretical calculations are in good agreement. This work facilitates the understanding of electronic speckle pattern interferometers and their applications in visualizations of acoustic waves for undergraduate physics laboratories.