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Unformatted text preview: E = 30 x 106 psi
υ = 0.3
ρ = 7.4167 x 10-4 lb-sec2/in4
C = 57480 in/sec
(speed of sound in water)
ρ = 9.6333 x 10-5 lb-sec2/in4 Geometric Properties
a = 10 in
b = 30 in
t = .25 in Analysis Assumptions and Modeling Notes
For this problem, the fluid is assumed as extending only to a finite radius b where the pressure Po is zero and b
is taken to be 30 inches. From the reference, this assumption should result in an error of less than 1% compared
to the frequency for an unbounded fluid (b = ∞ ). The natural boundary conditions at the coordinate axes imply
that δP / δx = 0 at x = 0 and δP / δy = 0 at y = 0.
This problem is solved using two separate analyses. The first, using 3-D acoustic fluid elements (FLUID30) with
quadrilateral shell elements (SHELL63), and the second, using 2-D acoustic fluid elements (FLUID29) with 2-D
elastic beam elements (BEAM3).
In the first case, due to fluid-structure coupling involving unsymmetric matrices, the natural frequency is determined by performing a full harmonic (ANTYPE = 3) analysi...
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This note was uploaded on 12/09/2010 for the course DEPARTMENT E301 taught by Professor Kulasinghe during the Spring '09 term at University of Peradeniya.
- Spring '09
- The Land