Dynamic analysis of risers subjected to random waves
- Agip S.p.A., Milan (Italy). Engineering Research and Development Dept.
- Snamprogetti S.p.A., Fano (Italy)
The paper presents the results of a series of measurements performed on a full scale instrumented riser. The test set up is comprehensively described in a previous paper by Campelli et al. (1992). In particular, in this paper vortex shedding induced vibrations (VIV) under oscillatory flow conditions, are discussed. Response trajectories and hydrodynamic loads are analyzed at two locations, 53% and 62% of the riser length from the bottom hinge. Maximum orbital velocities measured at the two sections, correspond to Keulegan-Carpenter number (KC) of 12 and Reynolds number (Re) of 5 {times} 10{sup 4}. In time series, VIV are characterized by excitation during half wave cycles overcoming a certain KC threshold, which is followed by decaying oscillations as a consequence of structural and fluid dynamic damping during half wave cycles characterized by smaller KC. Results are compared with Bearman (1988), using the equivalent KC method proposed by Srinivasan (1990). Response trajectories of cross sections are in accordance with the observations of Sarpkaya (1995). Presented results are preliminary and further analyses are in progress.
- OSTI ID:
- 449740
- Report Number(s):
- CONF-9606279--; ISBN 0-7918-1490-4
- Country of Publication:
- United States
- Language:
- English
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