Acoustic Method for the Suppression of Acoustic and Aerodynamically Induced Vibration on Structures

Abstract

The close relationship between noise and vibration is reviewed and analyzed for the suppression of noise and vibration in structures. The suppression of noise and vibration by acoustic means are addressed. For the first, an analysis is carried out by representing noise by monopoles and higher harmonics, and to devise a straight-forward method to counter their influence by selective secondary acoustic source. The second problem is analyzed using a methodology developed earlier for the computational scheme for the calculation of the acoustic disturbance to the aeroelasticity of structures. The generic approach of the latter consists of three parts. The first is the formulation of the acoustic wave propagation governed by the Helmholtz equation by using boundary element approach, to allow the calculation of the acoustic pressure on the acoustic-structure boundaries. The structural dynamic problem is formulated using finite elements. The third part involves the calculation of the unsteady aerodynamics loading on the structure using generic unsteady aerodynamics computational method.