The influence of an elastic coating on the diffraction of flow noise by an inhomogeneous flexible plate

✍ Scribed by M.S. Howe

• Publisher: Elsevier Science
• Year: 1987
• Tongue: English
• Weight: 942 KB
• Volume: 116
• Category: Article
• ISSN: 0022-460X
• DOI: 10.1016/s0022-460x(87)81323-8

✦ Synopsis

An analysis is made of the acoustic diffraction radiation produced by low Mach number turbulent boundary layer flow over a rectilinear joint in a plane flexible wall. The wall is modeled by a thin flexible plate consisting of two semi-infinite sections connected at their edges at the joint, which is transverse to the mean flow. A uniform, homogeneous elastic coating is interposed between the flow and the plate in order to reduce flow induced vibrations and the intensity of the scattered sound. For a clamped joint the dominant source of the diffraction radiation is the interaction with the joint of flexural waves in the coated plate which are excited at resonance by low wavenumber components of the turbulence wall pressure. Specific results are given for a "pc-coating" applied to a steel plate in water. The attenuation of the diffraction radiation is shown to attain maximal values when the coating thickness exceeds about four times that of the plate, provided that the loss factor of the coating is sufficiently large.