Experimental determination of wind speed and direction using a three microphone array

Recent studies indicate that the major sources of wind noise (under 50 Hz) measured on outdoor microphones is due to turbulent eddies moving across the microphone [S. Morgan and R. Raspet, J. Acoust. Soc. Am. 92, 1180–1183 (1992)]. Taylor’s frozen turbulence hypothesis states that these eddies retain their shape over a distance large compared to the size of the eddy. Thus it may be reasonable to assume that each eddy presents a specific acoustic signature that remains somewhat stable over a finite distance and time. If this is true, the cross correlation time for signals from two microphones a known distance apart should correspond to the travel time for an eddy to traverse the distance between the microphones. Assuming that the speed and direction of the eddy is the same as the ambient wind, enough information exists to calculate the wind speed and direction.