Active Control of Vibration and Radiated Sound of a Submerged Circular Plate

Complex analysis of characteristic of underwater noise allows to find several features typical for underwater noise produced by ships as well as correlations between mechanical activity of ship’s mechanism and generated underwater sound. Their vibration activity might be reduced by applying active treatments utilising piezoelectric sensors and actuators. The paper explores the potentials of active control of vibrations and sound through the application of a thin round plate clamped on the edges in a rectangular enclosure. The plate is loaded on one side by heavy fluid (water) and on the other side has contact with an air. On the side of the gaseous medium, eight piezoelectric elements are bonded to the plate with a thin layer of glue. Measurements of the acoustic pressure were taken over the whole length of the aquarium, for the fixed position of a hydrophone in the vertical and for variable height yet in a fixed distance from the radiation source. The finite element method analysis was performed, with the application of ANSYS computer package. The numerical solutions were confirmed experimentally.