Related Experiment Video
Updated: Jan 7, 2026
08:53
The Measurement of Unsteady Surface Pressure Using a Remote Microphone Probe
Published on: December 3, 2016
7.3K
Acoustic attenuation performance through a constricted duct improved by an annular resonator
Qipeng Feng1, Zhenyu Huang, Gaokun Yu
1Department of Marine Technology, Ocean University of China, Qingdao 266100, China fengqipeng@163.com, yellowshower@163.com, gkyu@ouc.edu.cn.
The Journal of the Acoustical Society of America
|October 15, 2013
Summary
An annular resonator significantly enhances acoustic attenuation in constricted ducts. This study introduces a Green
Area of Science:
- Acoustics
- Fluid Dynamics
- Mechanical Engineering
Background:
- Constricted ducts often exhibit poor acoustic attenuation.
- Annular resonators offer potential for noise control applications.
Purpose of the Study:
- To investigate the acoustic attenuation performance of an annular resonator in a constricted duct.
- To develop a theoretical method for calculating transmission loss.
Main Methods:
- Utilizing a Green's function method for a semi-infinite circular duct.
- Assuming uniform velocity distributions at key interfaces.
- Employing an analogous acoustical circuit model.
Main Results:
- The annular resonator greatly improves acoustic attenuation.
- Higher-order evanescent modes are accounted for by an effective extra length.
- Experimental validation confirms the theoretical predictions.
Conclusions:
- Annular resonators are effective for enhancing acoustic attenuation in constricted ducts.
- The Green's function method provides an accurate prediction of transmission loss.
- The proposed model accurately describes resonance phenomena.
Related Concept Videos
01:23Parallel Resonance
491
The parallel RLC circuit is an arrangement where the resistor (R), inductor (L), and capacitor (C) are all connected to the same nodes and, as a result, share the same voltage across them. The parallel RLC circuit is analyzed in terms of admittance (Y), which reflects the ease with which current can flow. The admittance is given by:
491
01:14Sound Waves: Resonance
3.2K
Resonance is produced depending on the boundary conditions imposed on a wave. Resonance can be produced in a string under tension with symmetrical boundary conditions (i.e., has a node at each end). A node is defined as a fixed point where the string does not move. The symmetrical boundary conditions result in some frequencies resonating and producing standing waves, while other frequencies interfere destructively. Sound waves can resonate in a hollow tube, and the frequencies of the sound...
3.2K
01:24Characteristics of Series Resonant Circuit
537
Series resonance occurs in a circuit containing inductive (L), capacitive (C), and resistive (R) elements connected sequentially. At the resonance frequency, the inductive and capacitive reactances are equal in magnitude but opposite in sign, effectively canceling each other. This causes the circuit's impedance is minimal, primarily determined by the resistance R. The resonant frequency of an RLC circuit is defined as:
537
01:19Concept of Resonance and its Characteristics
6.0K
If a driven oscillator needs to resonate at a specific frequency, then very light damping is required. An example of light damping includes playing piano strings and many other musical instruments. Conversely, to achieve small-amplitude oscillations as in a car's suspension system, heavy damping is required. Heavy damping reduces the amplitude, but the tradeoff is that the system responds at more frequencies. Speed bumps and gravel roads prove that even a car's suspension system is not...
6.0K
01:26Resonance in an AC Circuit
2.4K
The property of an inductor makes it resist any change in the current passing through it, while the property of a capacitor is to build up the charge across its terminals. Hence, if an inductor and capacitor are connected in series, they have opposite effects on the relative phase between current and voltage. The current through the circuit undergoes forced oscillation at the frequency of the source. The resistance term in an R-L-C circuit acts as a damping term because power is dissipated...
2.4K
01:17Design Example: Underdamped Parallel RLC Circuit
595
Consider designing an oscillator circuit, a crucial component in various electronic devices and systems. The objective is to create an oscillator circuit with specific characteristics: a damped natural frequency of 4 kHz and a damping factor of 4 radians per second. To accomplish this, a parallel RLC circuit is employed, known for its ability to sustain oscillations at a resonant frequency. In this case, the damping factor is pivotal in achieving the desired performance.
Starting with a fixed...
Starting with a fixed...
595