Turbulence-shear interaction pressure contributions to wind noise.

Abstract

In an earlier paper [Raspet et al., J. Acoust. Soc. Am. 123, 1260–1269 (2008)], the mean shear‐turbulence interaction pressure predicted by George et al. [J. Fluid Mech. 148, 155–191 (1984)] was calculated for outdoor wind noise measurements. It was found that the mean shear‐turbulence interaction pressure predictions overestimated the spectral levels at low wave numbers and were not consistent with measurements. A new calculation based on Kraichnan’s method [J. Acoust. Soc. Am. 28, 378–390 (1956)] includes two significant improvements: It uses a logarithmic wind velocity profile instead of a linear wind velocity profile, and it models the reduction in the vertical turbulence spectrum as the ground surface is approached. The effects of the change in vertical spectrum with height and the curvature of the wind profile are analyzed by comparing the two calculations. The height dependence of the predicted turbulence‐shear interaction pressure spectrum is also calculated. The predictions with the improved method agree with measurements made within large (1.0 m) wind‐screens. [Research supported by the U.S. Army TACOM‐ARDEC at Picatinny Arsenal, NJ.]