A prediction method of the acoustical properties of multilayered noise control materials in standing wave-duct systems

2006 ◽  
Vol 298 (1-2) ◽  
pp. 350-365 ◽  
Author(s):  
C.-M. Lee ◽  
Y.S. Wang
Keyword(s):  
Standing Wave ◽  
Noise Control ◽  
Prediction Method ◽  
Acoustical Properties ◽  
Duct Systems ◽  
Wave Duct

A Standing Wave-Duct System for Acoustical Property Prediction of Multi-Layered Noise Control Materials

2011 ◽  
Vol 378-379 ◽  
pp. 27-30
Author(s):  
Yan Song Wang ◽  
Tao Zhang ◽  
Na Chen ◽  
Jie Lei
Keyword(s):  
Standing Wave ◽  
Transfer Matrix ◽  
Noise Control ◽  
Transmission Loss ◽  
Cavity Method ◽  
Duct System ◽  
Multilayer Material ◽  
Property Prediction ◽  
Wave Duct ◽  
Acoustical Property

Based on a hybrid transfer-matrix method, a new standing wave-duct system with four microphones for acoustical property prediction of multi-layered noise control materials is developed in this paper. In this system, the two-load method (TLM) and two-cavity method (TCM) are used for computing the transfer matrix of each material sample. The transfer matrices saved in a database in the system hardisk may be selected for predicting both the absorption ratio and transmission loss of a multi-layered treatment of materials. Verification results suggest that the newly designed standing wave-duct system is effective for acoustical prediction of multilayer material configurations.

A hybrid method of predicting the acoustical properties of multi-layered materials

2021 ◽  
pp. 107754632110381
Author(s):  
Zechao Li ◽  
Lin Yang ◽  
Hongbin Ren ◽  
Sizhong Chen ◽  
Zheng Liu ◽  
...  
Keyword(s):  
Noise Control ◽  
Transmission Loss ◽  
Hybrid Approach ◽  
Sound Transmission ◽  
Normal Incidence ◽  
Layered Materials ◽  
Acoustical Properties ◽  
Transmission And Reflection Coefficients ◽  
Standing Wave Tube ◽  
Laminated Materials

Many numerical and measuring approaches are widely used in predicting and analysing the acoustic performances of laminated materials for noise control applications. However, numerical methods generally require a set of non-acoustic parameters, and the measuring methods are not available for exceedingly thick materials. The main aim of this article is to address a hybrid approach of evaluating the normal incidence sound transmission loss and absorption coefficients of multi-layered materials. This method is performed with some special parameters that contain the sound transmission and reflection coefficients of each sub-layer of a multi-layer specimen and can be measured by a standing wave tube system. The accuracy and feasibility of the present method are validated by the experimental and numerical comparisons between different methods and samples. Moreover, this present approach can be applied as a numerical tool of estimating the acoustical behaviours of multi-layered structures in noise control treatments, such as automotive, building and aerospace industries.

Noise Generation in Ventilation Systems by the Interaction of Airflow with Duct Discontinuities: Part 1 Bends

2007 ◽  
Vol 14 (3) ◽  
pp. 179-202 ◽  
Author(s):  
D. C. Waddington ◽  
D. J. Oldham
Keyword(s):  
Pressure Loss ◽  
Characteristic Curve ◽  
Prediction Method ◽  
Radius Of Curvature ◽  
Large Radius ◽  
Aspect Ratios ◽  
Potential Source ◽  
Duct Systems ◽  
Standard Values ◽  
Loss Coefficients

Discontinuities in air duct systems give rise to turbulence and some of this turbulence results in airflow generated noise. One potential source of flow generated noise in ducts is the presence of a bend. Various strategies are employed to reduce turbulence by smoothing the flow around a bend, such as the use of turning vanes, large radius of curvature and the associated use of splitters, and these will also affect the noise generated. Recent work on the prediction of airflow generated noise in ducts based upon pressure loss characteristics is applied to a range of bends including mitred bends, with and without turning vanes, and radiussed bends, with and without splitters. The effect of bends with different aspect ratios is also examined. An excellent collapse of measured data onto a single characteristic curve is reported for each configuration based upon standard values of pressure loss coefficients. It is suggested that these characteristic curves might form the basis for a practical prediction method.

Sign in / Sign up

Export Citation Format

Share Document