Measurement Effects Study of Microphone on Fluctuating Pressure of Boundary Layer
Aiming at the precise flight measurements of acoustic field near the after-body of a transport aircraft, based on an anechoic jet flow experimental facility, B&K4948 microphone was adopted for real installed configuration simulation. The dynamic measuring system is constructed with acoustic spectrum analysis and hot wire anemometer measurement. A series of experiments for different boundary layer flow structure with various microphone protuberance heights are carried out, and the relationship between load spectrum of pressure fluctuation and the flow structure of boundary layer is analyzed, the interference effect of sound measurement component on the acoustic and fluid field was also achieved. The results demonstrate that there are differences of fluctuating pressure spectrum between different boundary flow in subsonic and the fluctuating pressure spectrum are not sensitive to the acoustic measuring element with limited protrusion height in fully developed turbulent boundary layer.
Keywordsboundary layer fluctuating pressure protuberance flow interference
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