Noise reduction and power generation in blower duct using Helmholtz resonator with piezoelectric diaphragm

noise reduction efficiency of helmholtz resonator in simulated channel of hvac system

abstract background: given the fact of irrecoverable consequences of noise in industrial societies and the environment, acoustic filter (silencer) is an instrument which obstacles the transmission of sound waves. a sort of this silencer is helmholtz resonator (branch amplifier) which comes to sound appropriate for low and below 200 hz frequencies in fan and channel noise. the purpose of this ar...

An Experimental Investigation on Noise Reduction by Using Modified Helmholtz Resonator

A detailed tutorial for evaluating in-duct net acoustic power transmission in a circular duct with an attached cylindrical Helmholtz resonator using transfer matrix method

The transfer matrix method has been extensively explored by many researchers for analysing acoustic duct systems. However, there does not exist a comprehensive source that elaborates the use of transfer matrix method for evaluating the performance of acoustic filters. The current approach describes a detailed step-by-step method for evaluating induct net acoustic power transmission for a harmon...

Electrical Power Generation Using Piezoelectric Crystal

The usefulness of most high technology devices such as cell phones, computers, and sensors is limited by the storage capacity of batteries. In the future, these limitations will become more pronounced as the demand for wireless power outpaces battery development which is already nearly optimized. Thus, new power generation techniques are required for the next generation of wearable computers, w...

Helmholtz resonator with extended neck.

Acoustic performance of a concentric circular Helmholtz resonator with an extended neck is investigated theoretically, numerically, and experimentally. The effect of length and shape of, and the perforations on the neck extension is examined on the resonance frequency and the transmission loss. A two-dimensional analytical method is developed for an extended neck with constant cross-sectional a...