Active control of structural intensity and radiated acoustic power from an infinite point-excited submerged Mindlin plate

Abstract

In this paper, the active vibrational structural intensity (VSI) in, and the radiated acoustic power from an infinite elastic plate in contact with a heavy fluid is modeled by the Mindlin plate theory. The plate is excited by a point force, which generates a vector-active VSI field in the plate. The resulting acoustic radiation generates an active acoustic intensity (AI) in the fluid medium. The displacement, shear deformation, VSI vector map, radiated acoustic pressure, and the AI vector map are computed. One, two, or four synchronous point controllers are placed symmetrically with respect to the point force on the plate. Minimization of either the structural intensity at a reference point or the total radiated acoustic power is achieved. Below coincidence, a significant portion of the point force input power is trapped in the plate in the form of VSI. The total radiated power is calculated by use of the input power from the source, the controllers, and the VSI. Above coincidence, a significant portion of the input source power is leaked to the fluid in the form of AI, so that the acoustic radiated power is equal to the input power from the source and the controllers.