Laboratory Investigation of Long Riser VIV Response

In order to address the response of a long cylindrical riser in current, design codes (like Vandiver, 1983) require lift and drag coefficients of 2-D sections. Uncoupling the flexible response from the loading these design codes will determine the flexural response based on sectional stiffness and mass coefficients. However the physics of VIV behavior indicate that the hydroelastic response is significant. Therefore a study has been initiated to research the 3-D response of a part of a long riser in current by experiments. A circular steel pipe of 16 mm diameter and 12.6 m long was towed horizontally in a towing tank at speeds between 0.5 and 3.0 m/s and with pretensions between 0.5 and 2.5 kN. Measurements were made of the drag loads, the acceleration and the bending moments. State-of-theart fibre optical measuring techniques were deployed to obtain detailed insight into the complex VIV response of the test pipe. The first analysis of the test data shows a very complex response, including strong coupling between cross flow and in-line motions, beating, multimode response, traveling wave response, etc. Further analysis will continue and additional results will be published later.

This paper is copyrighted material and cannot be shared. Due to copyright policy MARIN is not allowed to reproduce and distribute papers written for and presented at the OTC (Offshore Technology Conference), ISOPE (International Ocean and Polar Engineering Conference) and SPE (Society of Petroleum Engineers). You can order these papers through
www.OnePetro.org.

For this specific paper follow this link.