Proceedings of the Thirty-second (2022) International Ocean and Polar Engineering Conference
Shanghai, 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

Analysis of a Tethered Underwater Vehicle Under the Influence of Sea Current with Adaptive Mesh
Shunyuan Xu1, Jiaming Wu1, Chenghua Ma2, Haiyan Lv2, Xianyuan Yang 1, Tian Zhang1
1Department of Naval Architecture and Ocean Engineering
South China University of Technology, Guangzhou, Guangdong, China
2Guangzhou Shunhai Shipyards Ltd. Guangzhou, Guangdong, China

ABSTRACTThe paper proposes a new modeling of the dynamic behavior of theunderwater vehicle coupling the cable model with the finite segment
approach. The hydrodynamic performance of underwater vehicle andthe umbilical cable under different sea current velocity is analyzed.
Numerical simulation is adopted to computational fluid dynamics (CFD)
technique, including overset mesh, adaptive mesh. The experimental
result verifies the validity of the numerical method. The numericalresults show that the influence of the cable’s shape cannot be simplified,which produces some unstable forces in the y-direction when thetethered underwater vehicle is towed in the three-dimensional flow
field.
KEY WORDS: finite segment approach; tethered underwater vehicle;hydrodynamic performance; overset mesh; adaptive mesh;

INTRODUCTION
The tethered underwater vehicle is widely used in exploring ocean
resources and investigating the marine environment. It usuallycomprises hydrofoils, umbilical cable, and ducted propellers(Christ R.
D. and Wernli R L, 2013). The tethered underwater vehicle ismanipulated by the control equipment and influenced by multiplehydrodynamic factors. In order to investigate the maneuverability andhydrodynamic performance of the tethered underwater vehicle,
considerable research about the control equipment and the shape of thetethered underwater vehicle carried out.
In investigating the influence of the ducted propeller on the underwater
vehicle, Wu et al. (2015) investigated the thrust characteristics of theducted propeller in the flow field of an underwater vehicle in turning
motion. De Barros and Dantas (2012) discussed the effect of a propeller
duct on the underwater vehicle’s maneuverability by employing anumerical (CFD) simulation and semi-empirical, ASE approaches.
Zhou and Zhao (2020) investigated the influence of four thruster
interactions and layouts on the underwater vehicle.

vehicle. Li et al. (2021) optimized the shape of the underwater vehicle
and hydrofoils to decrease the average periodic resistance. Satoru andYutaro (2021) investigated the lift and drag of the hydrofoils of theglider is studied and the characteristics of the blended wing body near asea bottom based on CFD analysis. Wu et al. (2021)investigated themaneuverability and hydrodynamic performance of the underwater
vehicle when the hydrofoils rotated in -30°~30°. Xu et al. (2022)
discussed the underwater vehicle’s motion controlled by the hydrofoils
under the influence of the cnoidal wave and quantitatively analyzed thewave influence on the hydrofoil.
The umbilical cable is also taken into account as a significant factor in
influencing the underwater vehicle’s motion. Wu and Chwang (2000)
utilized the finite difference method to establish a three-dimensionalmodel of a tethered two-part underwater vehicle. Buckham et al. (2004)
developed a finite element cable model to simulate the motion of slack
marine cables. Vu et al. (2017) investigated the umbilical cable’s
influence on the underwater vehicle’s surge, heave, sway and turning
motion with a catenary method. Suzuki et al. (2018) investigated themechanical properties of the cable and its influence on the underwater
vehicle with the absolute nodal coordinate formulation’s method.
Zhang et al. (2018) discussed the underwater vehicle’s trajectory
without hydrofoil and analyzed the influences of the cable’s parameteron it when the underwater vehicle turned around. Nørve Eidsvik and
Schjølberg (2018) presented a novel three-dimensional cable model foran underwater vehicle using Euler-Bernoulli beam theory and analyzed
the hydrodynamic parameters of the cable. Du (2019) numericallysimulates the dynamic behavior of a sonar cable array towed by anunderwater vehicle considering the influence of flow field disturbed by
the underwater vehicle and its propeller. Htun (2020) et al. proposed a
dynamic model of ROV’s tether cable with a radially multilayered
circular cross-section based on the absolute nodal coordinate
formulation(ANCF). Guan (2021) analyzes and simulates the towing
cable dynamics with the lumped mass method.
The above discussion shows that the researchers mainly discussed thehydrodynamic performance and motion of the underwater vehicle andits control equipment. It can be found that the multiple cable models areadopted to consider the effect of cable on the underwater vehicle, suchas finite difference method, catenary equation, lumped mass method,
absolute nodal coordinate formulation. However, the joint interaction

In discussing the effect of the hydrofoil, Font (2011) et al. presented
the design and implementation of a turtle hydrofoil for an underwater

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