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论文类型：期刊论文

发表时间：2011-08-01

发表刊物：OCEAN ENGINEERING

收录刊物：SCIE、EI

卷号：38

期号：11-12

页面范围：1308-1322

ISSN号：0029-8018

关键字：Vortex-induced vibration; Flexible riser; Laboratory tests; Multi-mode response; Higher harmonics; Large aspect ratio

摘要：Laboratory tests have been conducted on vortex-induced vibration (VIV) of a long flexible riser towed horizontally in a wave basin. The riser model has an external diameter of 16 mm and a total length of 28.0 m giving an aspect ratio of about 1750. Reynolds numbers ranged from about 3000 to 10,000. Fiber optic grating strain gages are adopted to measure the dynamic response in both cross-flow and in-line directions. The cross-flow vibrations were observed to vibrate at modes up to 6 and the in-line reached up to 12. The fundamental response frequencies can be predicted by a Strouhal number of about 0.18. Multi-mode responses and the asymmetry of the bare pipe response in uniform flow were observed and analyzed. The experimental results confirmed that the riser pipe vibrated multi-modally despite it being subject to a uniform current profile and all of the excited modes vibrated at the Strouhal frequency. The asymmetrical distribution of displacement mainly resulted from the modal composition. Higher harmonics of the VIV response such as the third, fourth and fifth harmonics frequencies were found to be steady over the entire duration of the test even if they varied along the length of the riser pipe. Crown Copyright (C) 2011 Published by Elsevier Ltd. All rights reserved.