Home > Publication > Ph.D. Dissertation  
Title A Study on Approximation Models for Acoustic - Structure Interaction in Exterior Problems
Author Lee Moonseok
Type KAIST Ph.D. Dissertation
Year of Pub. 2009
File Final_Thesis_KAIST_LeeMoonseok.pdf
Improved approximate models for external acoustic ¯eld interacting with °exible struc-
tures are developed. The basic form of the proposed models is obtained by a combination
of the Laplace-transformed retarded and advanced potentials with the weighting parameter
as part of the model equation. It is shown that the maximum attainable time-derivative
of convergent approximate models is two, hence any attempt to include higher orders will
lead to non-convergent models. First, the proposed model is theoretically compared to
the analytic solution and the classical models of the ¯rst-order and second-order Doubly
Asymptotic Approximations (DAA1 and DAA2) using modal equations for a sphere. Sec-
ond, transient responses of submerged spherical and cylindrical shells subjected to a series of
incident waves are performed using the proposed second-order boundary-element pressure
equation. To evaluate its performance, the results calculated by the proposed model are
compared with the classical analytical solutions and the Doubly Asymptotic Approxima-
tions(DAAs)'s results. Finally, through the application to a complex submerged structure,
the possibility for general applications of our approximation is shown. The results show
that proposed model o®ers improved accuracy especially for early time responses, exhibits
computational robustness, and maintains the desirable consistency in its impulse response
functions. Hence, our proposing model can be recommended as a candidate model equation
for system realization involving acoustic-structure interactions.