Microphone array measurement system for analysis of directional and spatial variations of sound fields

2002 ◽  
Vol 112 (5) ◽  
pp. 1980-1991 ◽  
Author(s):  
Bradford N. Gover ◽  
James G. Ryan ◽  
Michael R. Stinson
Keyword(s):  
Measurement System ◽  
Microphone Array ◽  
Spatial Variations ◽  
Sound Fields ◽  
Array Measurement

Analysis of source contribution to pass-by noise for a moving high-speed train based on microphone array measurement

Measurement ◽  
2021 ◽  
Vol 174 ◽  
pp. 109058
Author(s):  
Muxiao Li ◽  
Shuoqiao Zhong ◽  
Tiesong Deng ◽  
Ziwei Zhu ◽  
Xiaozhen Sheng
Keyword(s):  
High Speed ◽  
Microphone Array ◽  
High Speed Train ◽  
Source Contribution ◽  
Array Measurement

scholarly journals Regularised reconstruction of sound fields with a spherical microphone array

2013 ◽  
Author(s):  
Alba Granados ◽  
Finn Jacobsen ◽  
Efren Fernandez-Grande
Keyword(s):  
Microphone Array ◽  
Sound Fields

Synthetic Sound Source Generation for Acoustical Measurements in Turbomachines

2013 ◽  
Author(s):  
Michael Bartelt ◽  
Juan D. Laguna ◽  
Joerg R. Seume
Keyword(s):  
Wind Tunnel ◽  
Sound Source ◽  
Sound Propagation ◽  
Microphone Array ◽  
Sound Field ◽  
Acoustic Mode ◽  
Acoustic Excitation ◽  
Noise Emission ◽  
Noise Sources ◽  
Sound Fields

One of the greatest challenges in modern aircraft propulsion design is the reduction of the engine noise emission in order to develop quieter aircrafts. In the course of a current research project, the sound transport in low pressure turbines is investigated. For the corresponding experimental measurements, a specific acoustic excitation system is developed which can be implemented into the inlet of a turbine test rig and into an aeroacoustic wind tunnel. This allows for an acoustic mode generation and a synthesis of various sound source patterns to simulate typical turbomachinery noise sources such as rotor-stator interaction, etc. The paper presents the acoustical and technical design methodology in detail and addresses the experimental options of the system. Particular attention is paid to the design and the numerical optimization of the acoustic excitation units. To validate the sound generator during operation, measurements are performed in an aeroacoustic wind tunnel. For this purpose, an in-duct microphone array with a specific beamforming algorithm for hard-walled ducts is developed and applied to identify the source locations. The synthetically excited sound fields and the propagating acoustic modes are measured and analyzed by means of modal decomposition techniques. The measurement principles and the results are discussed in detail and it is shown that the intended sound source is produced and the intended sound field is excited. This paper shall contribute to help guide the development of excitation systems for aeroacoustic experiments to better understanding the physics of sound propagation within turbomachines.

Development of decomposition method of flow and sound fields around vehicle using MEMS microphone array

2019 ◽  
Vol 2019 (0) ◽  
pp. IS-04
Author(s):  
Kenta MIZUSHIRI ◽  
Tsukasa YOSHINAGA ◽  
Hiroshi YOKOYAMA ◽  
Akiyoshi IIDA
Keyword(s):  
Decomposition Method ◽  
Microphone Array ◽  
Sound Fields ◽  
Mems Microphone

Measurements of directional properties of reverberant sound fields in rooms using a spherical microphone array

2004 ◽  
Vol 116 (4) ◽  
pp. 2138-2148 ◽  
Author(s):  
Bradford N. Gover ◽  
James G. Ryan ◽  
Michael R. Stinson
Keyword(s):  
Microphone Array ◽  
Sound Fields

A Robust Industrial Procedure for Measuring Modal Sound Fields in the Development of Radial Compressor Stages

2017 ◽  
Vol 139 (6) ◽  
Author(s):  
Peter Limacher ◽  
Carsten Spinder ◽  
Marius C. Banica ◽  
Heinz-Jürgen Feld
Keyword(s):  
Measurement System ◽  
Noise Source ◽  
Sound Field ◽  
Temperature Stability ◽  
Noise Emission ◽  
Radial Compressor ◽  
Sound Fields ◽  
Compressor Inlet ◽  
Time Required ◽  
The Impact

The turbocharger is a significant noise source in large diesel engines, such as those used in container vessels. Its main noise source is the radial compressor, where improvements in silencers and turbocharger insulation have led to a considerable reduction of compressor inlet noise emission over the past few years. As a result, compressor outlet noise is now becoming increasingly significant for large engines. Recently, an in-house compressor testbed was upgraded by adding an acoustic modal measurement system (MSMS) that allows detailed investigation of modal sound fields inside the piping. This forms part of an updated compressor acoustic qualification procedure. This paper is an in-depth treatise of the characteristics of this modal measurement system. The calculation approach for the modal decomposition and a simplified alternative that assumes axial propagation, as well as relevant considerations, such as spatial resolution, averaging, and the use of multiple reference sensors, are addressed. Various measurement parameters, such as repeatability, measurement time, required temperature stability, pressure scaling, flow noise and their impact on measurement uncertainty were investigated. A successful validation of the modal sound measurement system with a well-known modal sound field at the compressor inlet is also presented. Finally, the characteristics of the modal sound fields of the compressor outlet of a typical modern turbocharger are discussed. Modal decompositions at the first two blade passing frequencies (BPFs) are presented for selected operating points (OPs). The response of total sound power levels (PWLs) to compressor speed along the operating line (OL) is examined by means of both the present and the simplified algorithm. A sensitivity analysis shows the impact of volume flow and rotational speed on the modal sound distribution.

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