It has been proposed that microphones mounted flush on the ground surface should measure reduced wind noise levels since the microphone does not disturb the flow and the wind velocity at the ground is small. However, there are pressure fluctuations induced on the ground by the interaction of the turbulent fluctuations above the ground with the average wind velocity gradient. Model calculations of the pressure spectrum under different wind velocity profiles have been developed based on the theoretical work of Kraichnan.1 Kraichnan calculated the turbulence-shear contribution to pressure fluctuations under boundary layer turbulence with an exponentially varying flow velocity profile. The calculations presented here incorporate measured outdoor spectra of the turbulence and different models of the velocity profile to investigate pressure fluctuation measurements outdoors at the ground surface. The predicted power spectral densities of the pressure are compared to each other and to measurements. The ultimate purpose of this research is to develop means to minimize wind noise interference in acoustic measurements. [Research supported by the U.S. Army TACOM-ARDEC at Picatinny Arsenal, NJ.]

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