Page 273 - Fluid-Structure Interactions Slender Structure and Axial Flow (Volume 1)
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254 SLENDER STRUCTURES AND AXIAL FLOW
water flow
1
-.
To reciprocating
mechanism
Wall-mounted
Hot-film anemometer
Cantilevered test pipe
To collecting tank I
on weighing scale (io (1 + pcos Or)
Figure 4.30 Schematic diagram of the apparatus used for parametric oscillations of pipes
conveying fluid (Paldoussis & Issid 1976).
agreement between theory and experiment is particularly poor in the case of the secondary
resonance. This is probably due to interference by forced vibration, transmitted through
the apparatus, which resulted in effectively widening the region of resonance.
The dynamical behaviour in the case of cantilevered pipes is described next. It was
found that unless the flow velocity was fairly close to the critical value, U,f, at which
the system loses stability by flutter in steady flow, the system remained stable, at least