Experimental investigation on a two-part underwater towed system

Wu, Jiaming; Chwang, Allen T.

doi:10.1016/s0029-8018(00)00030-5

Cited by 17 publications

(7 citation statements)

References 2 publications

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“…Sun et al [14] carried out a new nodal position finite element method to avoid the accumulated errors from time steps over a long-time simulation, and used the new method for towing simulations. To improve the stability of the towed vehicle, a two-part underwater towing method has been developed experimentally and numerically [15,16]. It is preferable to select a sufficiently long secondary cable to improve the hydrodynamic behavior of the towed vehicle for heave and pitch motions [17].…”

Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Model Investigations of the Underwater Towing of a Subsea Module

Zan

Guo

Yuan

et al. 2019

JMSE

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In underwater towing operations, the drag force and vertical offset angle of towropes are important considerations when choosing and setting up towing equipment. The aim of this paper is to study the variation in drag force, vertical offset angle, resistance, and attitude for towing operations with a view to optimizing these operations. An underwater experiment was conducted using a 1:8 scale physical model of a subsea module. A comprehensive series of viscous Computational Fluid Dynamics (CFD) simulations were carried out based on Reynolds-averaged Navier–Stokes equations for uniform velocity towing. The results of the simulation were compared with experimental data and showed good agreement. Numerical results of the vorticity field and streamlines at the towing speeds were presented to analyze the distribution of vortexes and flow patterns. The resistance components were analyzed based on the numerical result. It was found that the lateral direction was a better direction for towing operations because of the smaller drag force, resistance, and offset angle. Similar patterns and locations of streamlines and vortexes were present in both the longitudinal and lateral directions, the total resistance coefficient decreases at a Reynolds number greater than that of a cylinder.

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Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Model Investigations of the Underwater Towing of a Subsea Module

Zan

Guo

Yuan

et al. 2019

JMSE

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“…An underwater towed system consists of a towing mother ship, towed cable, and a towed vehicle and can generally be classified into two main types: one-part (shown in Figure 2) [4,5,6,7,8,9] and two-part towed vehicles [10,11,12,13,14,15] (shown in Figure 3). For one-part towed vehicles, the author in [4] proposes a robust motion control method based on a high-gain observer and a linear–quadratic–integral control scheme for a one-part underwater vehicle with movable wings.…”

Section: Introductionmentioning

confidence: 99%

“…A nonlinear, Lyapunov-based, adaptive output feedback control law was designed and shown to regulate pitch, yaw, and depth tracking errors to zero. The theoretical and experimental results in the investigation indicate that the hydrodynamic response of a towed vehicle to the wave-induced motion of a towing ship can be significantly reduced by applying a two-part tow method, and a relatively simple control method enables the towed vehicle to travel in a wide range with a stable attitude, which can be seen in [13,14]. In [15], the changing conditions of the motion characteristics of towed vehicles and cable configuration during the turning maneuvers of a towing ship were explored, and the turning radius and depth of the two towed vehicles changed greatly when the mother ship turned at a small radius at a large towing speed, which one should pay special attention to.…”

Section: Introductionmentioning

confidence: 99%

Joint Formation Control with Obstacle Avoidance of Towfish and Multiple Autonomous Underwater Vehicles Based on Graph Theory and the Null-Space-Based Method

Pang

Hong

2019

Sensors

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In this study, a new joint formation combined with a two-part underwater towed vehicle (towfish) with multiple autonomous underwater vehicles (AUVs) was investigated. A triangular structure formation was established based on graph theory, in which the main point is the secondary towed vehicle acting as the “leader,” and the other two points are AUVs acting as “followers.” The excellent real-time performance and high flexibility of the towfish is highlighted, and the communication delay and fixed routine of AUVs can be avoided simultaneously. As to the obstacle avoidance, the null-space-based behavioral approach is proposed. On the basis of this approach, the formation task moving to the target is decomposed into different subtasks, and the obstacle avoidance subtask is set as the highest priority. The vector of the low-level task is projected to the null space of the high-level task vector, and the integrated task output is used as the final output function. The low-level task is partially or completely accomplished while handling the higher task; therefore, the mutual conflict between different level targets can be avoided. Moreover, the corresponding task functions are designed in accordance with different subtask priorities. The comprehensive output function of formation motion is deduced and established to ensure that obstacles can be avoided effectively. Furthermore, simulation results demonstrate the effectiveness and feasibility of the proposed method in a complex underwater environment with obstacles.

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“…Kouh and Suen [8] studied issues based on three-dimensional potential flow theory by taking a highlevel panel method as the basis for their research, and thus they made the dual distribution and Gaussian field measurement suitable for the potential flow problem. In their study, Wu and Chwang [25] suggested a hydrodynamic underwater system attached to a primary wire, a two-piece vehicle capable of doing easy maneuvers, towed actively in the horizontal position, and vertically bearing control surfaces, and they discovered the mass of the vehicle by making use of threedimensional potential flow theory. In their research, Xu and the others [30] obtained experimentally the drifting resistance generated during the fixed speed horizontal movement by means of the Rankine ovoid and as a function of the Froud and Reynolds count number.…”

Section: Introductionmentioning

confidence: 99%

Modeling of Flow Around a Solid Body in Free and Restricted Fluidal Media

Süner

2015

Progress in Clean Energy, Volume 1

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Design has become one of the most essential tasks for human beings throughout the history of mankind. The accurate modeling and analysis of solid bodies moving in free fluid media (such as canals) for velocity, pressure, and forces have become quite significant. In conjunction with this, it is a challenging task to design solid bodies with complex geometries and structures in multidimensional form and it needs the utmost care and attention. Moreover, it is inevitable to develop and design some new systems that will enable us to reduce the energy requirements to minimum levels because nowadays saving energy has become one of the hottest issues for attaining sustainability. In this study, energy-efficient and -effective solid bodies are designed and analyzed by developing a two-dimensional model to study the distributions of flow velocity, pressure, and forces in free and restricted environments. The generalized model solutions are achieved in MATLAB. The results are then discussed for optimum conditions.

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Experimental investigation on a two-part underwater towed system

Cited by 17 publications

References 2 publications

Experimental and Numerical Model Investigations of the Underwater Towing of a Subsea Module

Experimental and Numerical Model Investigations of the Underwater Towing of a Subsea Module

Joint Formation Control with Obstacle Avoidance of Towfish and Multiple Autonomous Underwater Vehicles Based on Graph Theory and the Null-Space-Based Method

Modeling of Flow Around a Solid Body in Free and Restricted Fluidal Media

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