Proceedings of the Thirty-second (2022) International Ocean and Polar Engineering ConferenceShanghai, China, June 5–10, 2022
Copyright © 2022 by the International Society of Offshore and Polar Engineers (ISOPE)
ISBN 978-1-880653-81-4; ISSN 1098-6189

www.isope.org

Experimental and Analytical Investigation of Dynamic Stability of a Cantilevered Pipe Aspirating FluidYongqi Ma1, Yunxiang You1,2,3, Aichun Feng 1,2,3*, Ke Chen1,2,3
1 State Key Laboratory of Ocean Engineering, Shanghai Jiao Tong University, Shanghai, China
2 School of Naval Architecture, Ocean&Civil Engineering, Shanghai Jiao Tong University, Shanghai, China
3 Shanghai Jiao Tong University Yazhou Bay Institute of Deepsea Technology, Sanya, China

captured the instability of the pipe with increasing flow velocity.
Giacobbi and Rinaldi et al. (2012) and Rinaldi and Païdoussis (2020)
independently conducted experiments with air-flow. It was found that
aspirating pipe appeared flutter motions. Debut et al. (2010) conducted
experimental studies on two configurations of partially submerged
articulated pipe structures based on the theoretical model by Axisa(2010). Adiputra and Utsunomiya (2019) examined the stability of coldwater pipe conveying internal fluid for different pipe material, top joint
configuration and bottom supporting.
The present paper intends to study the fluid-induced vibration
phenomena of partially immerged cantilevered pipe aspirating fluid. The
experimental device is mainly composed of a circulating flow system, avertical cantilever pipe and measuring instrument. A cantilevered pipeof about 4 meters long was partially immersed in water. The vibration
frequency and amplitude of the pipe were measured for different pipeinternal flow velocity. Based on the experimental data, three different
boundary conditions are discussed respectively.

ABSTRACTThis paper considers the dynamics stability of a slender, flexible,cantilevered pipe transporting water flow from the free end to theclamped end. In the experimental, a cantilevered pipe of about 4 meters
long was partially immersed in water. The vibration frequency andamplitude of the pipe were measured for various pipe internal flow
velocity. For the analytical approach, the linear pipe vibration equationis briefly discussed and then solved by the harmonic differential
quadrature (HDQ) method in order to determine its stability
characteristics. The experimental results found that the internal flow
velocity have a significant effect on the pipe vibration. The cantilevered
pipe will become unstable due to flutter beyond a critical velocity. The
increasing of flow velocity will increase the pipe motion amplitude. In
addition, it has been observed that the pipe shows a complex motion
consisting of two alternating phases: an approximately flutter motion anda vibration similar to noise with a small amplitude.

KEY WORDS: dynamic stability; experimental and analytical;
harmonic differential quadrature method; flutter;

INTRODUCTION
The cantilevered pipe is a novel and most challenging device in the
floating structure for deep-sea mining. The internal flow causes theinstability of the cantilevered pipe, which may lead to failure of mining
operations. The theory of internal flow induced vibration of cantilevered
pipe has been extensively studied in the past few decades. Detailed
research progress of pipe conveying fluid can be found in thecorresponding published papers, such as Païdoussis (1970; 2014); Ge etal. (2019); Khodabakhsh et al. (2020); Ma et al. (2021).
Païdoussis and Luu (1985) conducted the dynamic characteristics of thecantilevered aspirating pipe applied in deep-sea mining. Païdoussis(1999) reevaluated the problem of cantilevered pipe aspirating fluid, andconsidered that the negative pressure at the pipe inlet is the main reason
for the stability of the cantilevered pipe. Kuiper and Metrikine (2005,2008) utilized theoretical and experimental methods to study thedynamic stability of a vertical cantilevered pipe aspirating fluid. They

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