ASA 127th Meeting M.I.T. 1994 June 6-10

2aNSa5. Effects of materials, damping, and static load constraints on the radiation from flow-excited plates.

Nathan C. Martin

Bolt Beranek and Newman, Inc., 70 Fawcett St., Cambridge, MA 02138

Turbulent boundary-layer (TBL) wall-pressure fluctuations due to fluid flow over the surface of a finite plate excite a flexural vibration response. At frequencies below the coincidence frequency the acoustically slow flexural waves radiate into the fluid as a result of interactions with boundary discontinuities. Relatively simple formulas can be derived that relate the radiated power due to TBL excitation to the dimensions and material properties of the plate. Static load requirements determine the relationship between plate thickness and support spacing for a given plate material. Alternative plate materials include various metals (steel, aluminum, titanium) and composites (e.g., glass or graphite-reinforced epoxy). Applied damping treatments can also be considered as a means of reducing plate response and radiation. This paper examines the issue of plate design for reduced radiation by considering material and damping alternatives in finite plates subject to static load constraints.