Wr. Graham, HIGH-FREQUENCY VIBRATION AND ACOUSTIC RADIATION OF FLUID-LOADED PLATES, Philosophical transactions-Royal Society of London. Physical sciences and engineering, 352(1698), 1995, pp. 1-43
To investigate the high-frequency vibration and acoustic radiation of
fluid-loaded structures, the model problem of a simply-supported plate
excited by a random pressure field is considered. The analysis is sta
ndard and yields a set of modal equations coupled by acoustic interact
ion terms. These terms not only complicate the equations, but also app
ear in a form that is difficult to evaluate numerically at high freque
ncies and mode numbers. The latter problem is resolved by deriving asy
mptotic expressions for the acoustic coefficients, and computational s
olution of the full, coupled modal equations then becomes feasible. By
comparing the results with the 'diagonal approximation' (the solution
when coupling is ignored), an improved characterization of the physic
al nature of the acoustic coupling is obtained, and new conditions for
its neglect are specified. The conditions are not stringent, implying
that the diagonal approximation will often be valid, and raising the
possibility of applying statistical energy analysis (SEA) to significa
ntly fluid-loaded structures. Modified sea results are derived, and fo
und to compare well with the modal solutions.