The Effect of Shear Sheltering on Trailing Edge Noise: A Theoretical Study

• Other Authors: Jimenez, Ignacio (author)
• Format: Others
• Language: English
• Published: Florida Atlantic University
• Subjects: Turbulent boundary layer; Trailing edges (Aerodynamics); Aeroacoustics; Boundary layer noise; Shear sheltering
• Online Access: http://purl.flvc.org/fau/fd/FA00013535

Shear sheltering is defined as the effect of the mean flow velocity profile in a boundary layer on the turbulence caused by an imposed gust. In aeroacoustic applications turbulent boundary layers interacting with blade trailing edges or roughness elements are an important source of sound, and the effect of shear sheltering on these noise sources has not been studied in detail. Since the surface pressure spectrum below the boundary layer is the primary driver of trailing edge and roughness noise, this thesis considers the effect that shear sheltering has on the surface pressure spectrum below a boundary layer. This study presents a model of the incoming turbulence as a vortex sheet at a specified height above the surface and shows, using canonical boundary layers and approximations to numerical results, how the mean flow velocity profile can be manipulated to alter the surface pressure spectrum and hence the associated trailing edge noise. The results from this model demonstrate that different mean velocity profiles drive significant changes in the unsteady characteristics of the flow. The surface pressure fluctuations results also suggest that boundary layers where the shear in the mean velocity profile is significant can be beneficial for the reduction of trailing edge noise at particular frequencies. === Includes bibliography. === Thesis (M.S.)--Florida Atlantic University, 2020. === FAU Electronic Theses and Dissertations Collection