AUTHOR=Feng Yunli , Li Sunwei , Chen Daoyi 

TITLE=Tensioned flexible riser vibrations under wave excitation, an investigation on the scale effect

JOURNAL=Frontiers in Marine Science

VOLUME=11

YEAR=2024

URL=https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2024.1372676

DOI=10.3389/fmars.2024.1372676

ISSN=2296-7745

ABSTRACT=<p>In order to study the scale effect in wave-structure interactions and the role that structure-related parameters (tension <italic>T</italic> or bending stiffness <italic>EI</italic>) plays, riser model tests under regular waves were conducted using the model with multiple geometric scales (1:15, 1:12 and 1:9) in a wave basin. The riser model used is a novel structural design combing the outer polyvinyl chloride pipe with the core steel rod which could be simplified as a cantilever beam. Different initial tension <italic>T</italic> acting on the riser are tested by adjusting the slotted weight. The results show that the amplitude varies in a cubic fashion with the distance from the fixed end. In addition, the influence of the wave period and top tension <italic>T</italic> on the amplitude are investigated, which ultimately leads to a dimensionless number π<sub>1</sub> = <italic>KC<sub>d</sub></italic>·<italic>TL</italic><sup>2</sup>/<italic>EI</italic> where <italic>KC</italic> is the classical Keulegan–Carpenter number (<italic>KC</italic>), <italic>EI</italic> shows the bending stiffness of the riser model and <italic>L</italic> gives the pipe length. With the <italic>KC</italic> number revised to take the distance from the fixed end into the calculation, this parameter provides a good measure in estimating the amplitudes of the riser vibrations induced by the waves.</p>