Understanding Roughness Noise: Progress in Analytical Modeling and Testing, Part 2—Comparison of Calculations to Data

This Part-2 paper applies Part 1’s theory of sheared rapid distortions to compute broadband noise from flow over large roughness elements, and compares those calculations to recent wind-tunnel measurements. The calculations suggest that shear effects are subdominant in the sound-production process. Post-processing of computed results brings out key features of the theory’s non-equilibrium distorting turbulence. A follow-up analysis makes possible the physical interpretation of the measured acoustic spectral densities in terms of the kinematics of the spatially non-uniform carrier flow.