Analysis of Static Flow Resistivity of a Modified Impedance Tube

Abstract

The static flow resistivity is a fundamental parameter for measuring and classifying the sound absorption behavior of various types of materials. Several methods have been developed for measuring the static flow resistivity acoustically. Most of these methods cannot be implemented directly in the standard tubes which are widely used for measurements of sound absorption coefficients and impedance as defined in ISO 10534.2. The accuracy of the proposed method and the tube is verified through finite element analysis and the feasibility to determine the static flow resistivity is validated through experiments. It is validated that the accuracy of the proposed method is highly dependent on the position of the acoustic center of the measurement microphones and the accuracy can be enhanced by increasing the back cavity depth and/or decreasing the measurement frequency.

Airflow resistance of acoustical fibrous materials: Measurements, calculations and applications

“…According to reported studies, airflow resistance is insensitive to frequency when the test frequency is approximately a few hundreds of hertz [6]. However, a small change in the movement of the acoustic centers of the microphones will result in large variations in the percentage of error, and thicker thickness of specimen is beneficial to increase the accuracy [52]. In addition, there are also some other methods to characterize airflow resistance.…”

Physical, Chemical, Morphological and Thermal Characterisation of Natural Fibers for Sound Absorption

“…Sansevieria cylindrica fiber was studied for its dynamic, mechanical, surface and thermal properties and the effect of alkali treatment on fiber properties and corresponding effects on the mechanical and thermal properties were analyzed [9]. Various other studies were done to characterize the properties of natural fibers, its composites and its nonwovens [1,[10][11][12][13][14][15][16].…”