Reduction of flow-induced trailing edge noise of semi-infinite flat plate by structural resonance

Abstract

A unique method for the reduction in flow-induced trailing edge noise scattering for a semi-infinite thin plate is proposed by utilizing short flexible panels mounted on the surface of the plate. The proposed configuration differs from conventional cantilevered elastic trailing edges due to the limitations of their structural integrity and applicability. The key idea is to design short panels that vibrate in structural resonance under the fluid loading for absorbing the energy from the flow to sustain their vibration. A time-domain direct aeroacoustic simulation coupled with structural dynamics is carried out at a low Reynolds number of 50,000 to explore the aeroacoustic-structural interactions. The effectiveness of noise reduction of the designed configuration is analyzed by comprehensive aeroacoustic analysis where a significant noise reduction is observed for the plate mounted with three flexible panels without any adverse effects on the plate aerodynamics. The structural analysis shows a systematic vibration pattern for all the panels which clearly indicates the presence of complex fluid-structural interaction under resonance conditions. Design strategy of the proposed configuration along with its limitations are also discussed.