Sound Source Localization - Small airduct ventilator noise: beamforming

This example shows a small ventilator used for creating an air flow inside air conditioning ducts. 2 configurations are tested, one original, and one where an artificial stall is introduced by placing a sheet of paper on the back air outlets. This case studies the influence of this modification on the ventilator blades. 
The original configuration is analyzed in figure 12. In low frequencies of 600-700Hz (left), the source localization is correct, as expected, but the dynamic range is rather large. The picture on the right shows the sound source localization at a mid-frequency range of 1100Hz. On figure 13 the analysis with artificial stall shows that sound sources shifted to the edge of the ventilator. 













Figure 12: Original configuration, low freq 625-700Hz, mid frequency 1050-1150Hz 













Figure 13: Stalled configuration, disturbance noise at mid frequency (left, 1040-1140Hz), and high frequency (right, 3580-4010Hz) 


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