Wr. Graham, THE EFFECT OF MEAN FLOW ON THE RADIATION EFFICIENCY OF RECTANGULAR-PLATES, Proceedings - Royal Society. Mathematical, physical and engineering sciences, 454(1968), 1998, pp. 111-137
Citations number
16
Categorie Soggetti
Multidisciplinary Sciences
Journal title
Proceedings - Royal Society. Mathematical, physical and engineering sciences
The acoustic power radiated by a rectangular plate bounded by a unifor
m mean flow is investigated. Asymptotic expressions for the modal radi
ation efficiency of a simply supported plate are derived, and confirme
d by comparison with numerical results. The asymptotic expressions sho
w that the frequency at which a mode becomes an efficient radiator is
reduced in the presence of mean flow, and hence that the critical freq
uency for a vibrating elastic plate is similarly lowered. The effects
of these changes on the radiation damping of an aircraft panel in crui
se, and on its radiation efficiency on landing, are investigated. The
asymptotic results are then extended to more general plate edge condit
ions via analysis of appropriate infinite and semiinfinite problems. H
ence the '3 dB rule'-that a plate with clamped edges, vibrating well b
elow the critical frequency, radiates twice the power of a plate with
simple supports-is shown to apply also in the presence of mean flow.