Low frequency drift oscillation of offshore guyed towers
- Indian Inst. of Tech., New Delhi (India)
The guyed towers being compliant offshore systems have very low natural frequencies and therefore, are susceptible to low frequency excitation. Since second order drift forces in random sea have very low frequency contents, they may induce significant responses in the guyed towers. The time history of the drift forces is generated by using a simulation technique which obtains time histories of the square of the slowly varying wave envelope and instantaneous frequency dependent drift coefficients. The latter is determined from the mean viscous drift force acting on the tower for regular waves having different periods, combined with specified current velocity and mass transport velocity. The response of the guyed tower to random drift forces is determined in iterative frequency domain and the guylines are replaced by nonlinear springs whose force-displacement relationship is determined from a separate cable analysis.
- OSTI ID:
- 403101
- Report Number(s):
- CONF-940409--; ISBN 1-880653-10-9
- Country of Publication:
- United States
- Language:
- English
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