Author A.W. van Elsacker
Title The Behaviour of Flexible Risers in Waves
Conference/Journal Offshore Technology Conference (OTC), Houston
Paper no. OTC1989-6168
Year 1989

In this paper results of flexible riser model tests will be discussed and compared with results of time domain simulations for regular and irregular wave conditions with current.

The model tests were performed at the Maritime Research Institute Netherlands (MARIN) with a large scale riser model instrumented to determine bending moments at a number of points along the riser. Motions of the riser were measured by means of underwater optical tracking systems. The riser top was attached to a mechanical oscillator programmed to carry out the motions of the attachment point of a tanker in irregular waves. Special attention was given to the correct phasing between riser motions and irregular waves. The calculations were performed with the MARIN riser analysis program DYNAFA.

Results of tests and calculations are compared for the riser top area. Correlation is obtained for both regular and irregular wave conditions. It is concluded that computations for irregular wave conditions provide valuable information in early design stage and can be used to extend the model test results.

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