A Wiener-Laguerre Model of VIV Forces Given Recent Cylinder Velocities
Slender structures immersed in a cross flow can experience vibrations induced by vortex shedding (VIV), which cause fatigue damage and other problems. VIV models that are used in structural design today tend to assume harmonic oscillations in some way or other. A time domain model would allow to cap...
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| Format: | Article |
| Language: | English |
| Published: |
Hindawi Limited
2011-01-01
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| Series: | Mathematical Problems in Engineering |
| Online Access: | http://dx.doi.org/10.1155/2011/414702 |
| Summary: | Slender structures immersed in a cross flow can experience
vibrations induced by vortex shedding (VIV), which
cause fatigue damage and other problems. VIV models
that are used in structural design today tend to assume
harmonic oscillations in some way or other. A time domain
model would allow to capture the chaotic nature of
VIV and to model interactions with other loads and nonlinearities.
Such a model was developed in the present
work: for each cross section, recent velocity history is
compressed using Laguerre polynomials. The compressed
information is used to enter an interpolation function to
predict the instantaneous force, allowing to step the dynamic
analysis. An offshore riser was modeled in this way:
some analyses provided an unusually fine level of realism,
while in other analyses, the riser fell into an unphysical
pattern of vibration. It is concluded that the concept is
promising, yet that more work is needed to understand
orbit stability and related issues, in order to produce an
engineering tool. |
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| ISSN: | 1024-123X 1563-5147 |