Related Experiment Video
Updated: Mar 3, 2026
07:28
Terahertz Microfluidic Sensing Using a Parallel-plate Waveguide Sensor
Published on: August 30, 2012
11.2K
Using one-dimensional waveguide resonators to measure phase velocities in bubbly liquids
Craig N Dolder1, Preston S Wilson1
1Applied Research Laboratories and Department of Mechanical Engineering, The University of Texas at Austin, 1 University Station C2200, Austin, Texas 78712, USA.
The Journal of the Acoustical Society of America
|May 4, 2017
Summary
Resonator techniques for dispersive materials are improved by accounting for repeating modes. This method expands the measurement range significantly, enhancing effective medium property extraction.
Area of Science:
- Acoustics
- Materials Science
- Wave Propagation
Background:
- Resonator techniques are valuable for characterizing effective medium properties of dispersive materials.
- Mode repetition due to dispersion can limit the applicability of traditional resonator methods.
- Understanding and addressing mode repetition is crucial for extending the useful frequency range.
Purpose of the Study:
- To investigate and overcome the limitations imposed by repeating modes in resonator measurements of dispersive materials.
- To develop a method for exploiting all relevant modes, including repeated ones, to expand the measurement range.
- To provide a theoretical framework for predicting mode repetition in such systems.
Main Methods:
- Utilized a resonance tube with tethered balloons to create a model dispersive effective medium.
- Performed resonator measurements to observe and analyze the behavior of acoustic modes.
- Employed direct measurement of mode shapes to identify and utilize repeated modes.
- Developed a theoretical model to predict the conditions under which modes repeat.
Main Results:
- Resonator measurements confirmed the occurrence of repeating modes in the created dispersive medium.
- Direct measurement of mode shapes enabled the exploitation of all longitudinal, radially symmetric modes.
- The developed method significantly increased the measurement frequency range from below 160 Hz to 3000 Hz (excluding stop bands).
- A theoretical model was established to accurately predict mode repetition.
Conclusions:
- Accounting for repeating modes is essential for maximizing the utility of resonator techniques in dispersive materials.
- Direct measurement of mode shapes provides a pathway to exploit a wider range of modes.
- The presented approach substantially broadens the effective frequency range for characterizing dispersive media.
- The study offers a method to address non-ideal resonator boundary conditions in dispersive systems.
More Related Videos
Related Concept Videos
01:09Deriving the Speed of Sound in a Liquid
1.0K
As with waves on a string, the speed of sound or a mechanical wave in a fluid depends on the fluid's elastic modulus and inertia. The two relevant physical quantities are the bulk modulus and the density of the material. Indeed, it turns out that the relationship between speed and the bulk modulus and density in fluids is the same as that between the speed and the Young's modulus and density in solids.
The speed of sound in fluids can be derived by considering a mechanical wave...
The speed of sound in fluids can be derived by considering a mechanical wave...
1.0K
01:28Standing Waves in a Cavity
1.6K
A household microwave and lasers are examples of standing electromagnetic waves in a cavity. When two conducting metal plates are placed parallel at the nodal planes, it creates a cavity where standing waves are formed. The cavity between the two planes is analogous to a stretched string held at the points x = 0 and x = L. Here, the distance 'L' between the two planes must be an integer multiple of half of the wavelength. The wavelengths that satisfy this condition are given by:
1.6K