The Quarterly Journal of Mechanics and Applied Mathematics Advance Access originally published online on October 4, 2007
The Quarterly Journal of Mechanics and Applied Mathematics 2007 60(4):397-421; doi:10.1093/qjmam/hbm015
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Resonances of an elastic plate in a compressible confined fluid


( Laboratoire POEMS, UMR 2706 CNRS/ENSTA/INRIA, ENSTA, 32 boulevard Victor, 75739 Paris cedex 15, France )
anne-sophie.bonnet-bendhia{at}ensta.fr
Corresponding author
jean-francois.mercier{at}ensta.fr
Received 24 May 2006.
Revise 15 May 2007.
| Abstract |
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We present a theoretical study of the resonances of a fluid–structure problem, an elastic plate placed in a duct in the presence of a compressible fluid. The case of a rigid plate has been largely studied. Acoustic resonances are then associated to resonant modes trapped by the plate. Due to the elasticity of the plate, we need to solve a quadratic eigenvalue problem in which the resonance frequencies k solve the equations
(k) = k2, where
are the eigenvalues of a self-adjoint operator of the form A + kB. First, we show how to study the eigenvalues located below the essential spectrum by using the min–max principle. Then, we study the fixed-point equations. We establish sufficient conditions on the characteristics of the plate and of the fluid to ensure the existence of resonances. Such conditions are validated numerically.