Abstract:The vortex shedding noise of rotating blade is a kind of typical directional sound source. However, the directivity of vortex shedding noise can’t be measured accurately due to blade rotating. Here, two planar arrays were used to study the acoustic imaging of sound source in two directions of parallel and vertical to the rotating surface of blade. In tests, different blade rotation azimuth positions were selected to perform beamforming acoustic imaging of vortex shedding aerodynamic noise. The directivity of vortex shedding noise was verified by comparing acoustic imaging results under different blade azimuth angles and array directions, and effects of different blade rotation azimuth angles on vortex shedding noise were analyzed. The test results verified the feasibility and effectiveness of the dual-array acoustic imaging measurement scheme. The comparison of imaging results showed that the rotating aerodynamic noise source of NACA0012 blade at 2.5 kHz is directional.
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