風洞の主流近傍に設置したマイクロホンアレイによる音源位置同定精度の改善(流体工学,流体機械)

概要

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In this study, we proposed a method to improve an accuracy of source localization in a wind tunnel tests by using microphone array. Based on an acoustic path model in passing through the free shear layer, the microphone array is installed adjacent to the main flow to avoid the refraction and dissipation in the free shear layer. The flow-induced noise caused by the interference with the main flow is also effectively reduced by calculating a cross spectrum between the respective outputs of 2 pairs of 2-D microphone array. The effects of these techniques are varified by the acoustic performance test with standard source device under wind condition. As a result, firstly, it was found out that the calculation method is effective even at the uniform wind velocity of 300km/h and enables the acoustic measurement adjacent to the main flow. Secondly, accurate noise source localization can be achieved by installing the microphone array along the line extended from the side wall of the wind tunnel nozzle adjacent to the main flow. The location error by this method is improved less than 10 mm compared with that measured outside of the free shear layer.
一般社団法人日本機械学会の論文
2008-07-25