Vortex-Induced Vibration Characteristics of an Underwater Manipulator in Pulsating Flow

Abstract

Vortex-induced vibration (VIV) of an underwater manipulator in pulsating flow presents a notable engineering problem in precise control due to the velocity variation in the flow. This study investigates the VIV response of an underwater manipulator subjected to pulsating flow, focusing on how different postures affect the behavior of the system. The effects of pulsating parameters and manipulator arrangement on the hydrodynamic coefficient, vibration response, motion trajectory, and vortex shedding behaviors were analyzed. Results indicated that the cross-flow vibration displacement in pulsating flow increased by 32.14% compared to uniform flow, inducing a shift in the motion trajectory from a crescent shape to a sideward vase shape. In the absence of interference between the upper and lower arms, the lift coefficient of the manipulator substantially increased with rising pulsating frequency, reaching a maximum increment of 67.0%. This increase in the lift coefficient led to a 67.05% rise in the vibration frequency of the manipulator in the in-line direction. As the pulsating amplitude increased, the drag coefficient of the underwater manipulator rose by 36.79%, but the vibration frequency in the cross-flow direction decreased by 56.26%. Additionally, when the upper and lower arms remained in a state of mutual interference, the cross-flow vibration amplitudes of the upper and lower arms were approximately 1.84 and 4.82 times higher in a circular-elliptical arrangement compared to an elliptical-circular arrangement, respectively. Consequently, the flow field shifted from a P+S pattern to a disordered pattern, disrupting the regularity of the motion trajectory.

Keywords

Underwater manipulator / Pulsating flow / Vortex-induced vibration / Trajectory / Overlapping mesh method

RIGHTS & PERMISSIONS

Harbin Engineering University and Springer-Verlag GmbH Germany, part of Springer Nature