• Title/Summary/Keyword: Towed cable

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Development of Cable for Towed Array Sonar System (예인 음탐기용 케이블 개발)

  • Yang, Seung-Yun;Kim, Jung-Suk;Kim, Chul-Min;Lee, Jin-Hee
    • Journal of the Korea Institute of Military Science and Technology
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    • v.19 no.5
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    • pp.559-566
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    • 2016
  • Cables for Towed Array Sonar System(TASS) were developed. In order to verify the performance of cables, environmental and operational conditions as well as functional requirements were investigated during design stage. Double armored high and low voltage integrated cable for towed body and two kinds of cables, armored and light weight power and optic hybrid cables for towed array sensor system were developed by modeling and simulation. Customized manufacturing process and test method, such as foam extrusion and dynamic fatigue test were applied to this development. In conclusion, underwater towed hybrid cable with high tensile strength and compact structure were developed.

A Numerical and Experimental Study on Dynamics of A Towed Low-Tension Cable

  • Jung, D.H.;Park, H.I.;Koterayama, W.
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2002.10a
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    • pp.191-196
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    • 2002
  • The paper presents a numerical and experimental investigation on dynamic behaviors of a towed low tension cable. In the numerical study, an implicit finite difference algorithm is employed for three-dimensional cable equations. Fluid and geometric non-linearity and bending stiffness are considered and solved by Newton-Raphson iteration. Block tri-diagonal matrix method is applied for the fast calculation of the huge size of matrices. In order to verify the numerical results and to see real physical phenomena, an experiment is carried out for a 6m cable in a deep and long towing tank. The cable is towed in two different ways; one is towed at a constant speed and the other is towed at a constant speed with top end horizontal oscillations. Cable tension and shear forces are measured at the top end. Numerical and experimental results are compared with good agreements in most cases but with some differences in a few cases. The differences are due to drag coefficients caused by vortex shedding. In the numerical modeling, non-uniform element length needs to be employed to cope with the sharp variation of tension and shear forces at near top end.

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Study on Eigenvalue Analysis for a Towed Cable - Free Boundary at the Bottom End (예인되는 케이블의 고유치 해석에 관한 연구 - 하부 끝단 자유 경계조건)

  • Jung, Dong-Ho;Kim, Hyeon-Ju;Moon, Deok-Soo;Lee, Seung-Won
    • Journal of Ocean Engineering and Technology
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    • v.23 no.1
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    • pp.74-80
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    • 2009
  • In this study, the static and modal analyses to find the characteristic of eigenvalues for a towed cable were with a free boundary condition at the bottom end carried out with numerical study. The resulting numerical code with finite element method was used to study sample problems for a cable with towing speeds. After tracing the equilibrium state with a towing speed through the static analysis, modal analysis on the basis of static results was performed. The static top tension for a critical towing speed is nearly 50 percent of what it was for a free hanging pipe. From static analyses, it is found that towing speed has a noticeable effect on top tension of a towed pipe. At a high towing speed, differences between the first and second periods become larger. Compared to the fundamental period for a free hanging pipe, that for a towed pipe with a critical towing speed is approximately 1.4 times larger. This result is very important point in that the lock in condition and tension of the towed cable system with top excitation can be predicted. The corrected close form solution to solve natural periods for a towed cable was presented in this study. The code is validated by comparison of the results of theoretical and numerical studies. Two results were in very good agreement. This study can contribute to predicting the lock-in condition and tension for a towed cable or pipe with top excitation.

SIMULATION OF FLUID-STRUCTURE INTERACTION OF A TOWED BODY USING AN ASYMMETRIC TENSION MODEL (비대칭 장력 모델을 이용한 예인 물체의 유체-구조 상호작용 모사)

  • Shin, Sang-Mook
    • Journal of computational fluids engineering
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    • v.16 no.1
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    • pp.7-13
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    • 2011
  • The fluid-structure interaction of a towed body is simulated using a developed code, which is based on the flux-difference splitting scheme on the hybrid Cartesian/immersed boundary method. To improve the stability in the coupling between the fluid and structure domains, a scheme is used, in which the effects of structure deformation are treated implicitly. The developed code is validated for the fluid-structure interaction problem through comparisons with other results on the vortex-induced vibration of elastically mounted cylinders. To simulate behavior of a towed body, an asymmetric tension modelling for a towing cable is suggested. In the suggested model, the tension is proportional to the elongation of the cable, but the cable has no effect on the body motion whenever the distance between the endpoints of the cable is smaller than the original length of the cable. The fluid-structure interactions of a towed body are simulated on the basis of different parameters of the towing cables. It is observed that the suggested tension model predicts the snapping for a shorter towing cable, which is in accordance with the reported results.

Dynamics modeling of a semi-submersible autonomous underwater vehicle with a towfish towed by a cable

  • Park, Jinmo;Kim, Nakwan
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.7 no.2
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    • pp.409-425
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    • 2015
  • In this paper, we employ a dynamics modeling method for investigating a multi-body dynamics system of semi-submersible autonomous underwater vehicles consisting of a towing vehicle operated near the water surface, a tow cable, and a towfish. The towfish, which is towed by a marine cable for the purposes of exploration or mine hunting, is modeled with a Six-Degree-of-Freedom (6-DOF) equation of motion that reflects its hydrodynamics characteristics. The towing cable, which can experience large displacements and deformations, is modeled using an absolute nodal coordinate formulation. To reflect the hydrodynamic characteristics of the cable during motion, the hydrodynamic force due to added mass and the drag force are imposed. To verify the completeness of the modeling, a few simple numerical simulations were conducted, and the results confirm the physical plausibility of the model.

Nonlinear Analysis of Underwater Towed Cable Using Robust Nodal Position Finite Element Method (강건 절점위치 유한요소법을 이용한 수중 예인 케이블의 비선형 거동해석)

  • Lee, Euntaek;Go, Gwangsoo;Ahn, Hyung Taek;Kim, Seongil;Chun, Seung Yong;Kim, Jung Suk;Lee, Byeong Hee
    • Journal of the Society of Naval Architects of Korea
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    • v.53 no.5
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    • pp.388-399
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    • 2016
  • A motion analysis of an underwater towed cable is a complex task due to its nonlinear nature of the problem. The major source of the nonlinearity of the underwater cable analysis is that the motion of the cable involves large rigid-body motion. This large rigid-body motion makes difficult to use standard displacement-based finite element method. In this paper, the authors apply recently developed nodal position-based finite element method which can deal with the geometric nonlinearity due to the large rigid-body motion. In order to enhance the stability of the large-scale nonlinear cable motion simulation, an efficient time-integration scheme is proposed, namely predictor/multi-corrector Newmark scheme. Three different predictors are introduced, and the best predictor in terms of stability and robustness for impulsive cable motion analysis is proposed. As a result, the nonlinear motion of underwater cable is predicted in a very efficient manner compared to the classical finite element of finite difference methods. The efficacy of the method is demonstrated with several test cases, involving static and dynamic motion of a single cable element, and also under water towed cable composed of multiple cable elements.

Study on dynamic behavior analysis of towed line array sensor

  • Shin, Hyun-Kyoung;Ryue, Jung-Soo;Ahn, Hyung-Taek;Seo, Hee-Seon;Kwon, Oh-Cho
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.4 no.1
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    • pp.9-19
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    • 2012
  • A set of equations of motion is derived for vibratory motions of an underwater cable connected to a moving vehicle at one end and with drogues at the other end. From the static analysis, cable configurations are obtained for different vehicle speeds and towing pretensions are determined by fluid resistance of drogues. Also the dynamic analysis is required to predict its vibratory motion. Nonlinear fluid drag forces greatly influence the dynamic tension. In this study, a numerical analysis program was developed to find out the characteristic of cable behaviour. The motion is described in terms of space and time coordinates based on Chebyshev polynomial expansions. For the spatial integration the collocation method is employed and the Newmark method is applied for the time integration. Dynamic tensions, displacements, velocities, accelerations were predicted in the time domain while natural frequencies and transfer functions were obtained in the frequency domain.

A Study on the Control of a Cable Spooling System for Towed Array Handling Winch (예인윈치 케이블 권선정렬 시스템의 제어에 관한 연구)

  • 조상훈;양승윤;정찬희;박래석
    • Journal of the Korea Institute of Military Science and Technology
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    • v.4 no.1
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    • pp.52-61
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    • 2001
  • The purpose of this paper is to study on the control of a self-activated cable spooling system for towed away handling winch using a hydraulic servo driving unit and a cable position measurement mechanism. To design a controller of the cable spooling system, it is carried out the analysis of the hydraulic servo system and derived the relationship of a parameters through the control theory. Also, it is derived from the control specfications using settling rotation angle and spooling safety ratio proposed to the analysis for the behavior of the system. The cable spooling system is tested and evaluated to validate the performance of the controller.

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A Study on the Control of a Cable Spooling System for Towed Array Handling Winch (예인윈치 케이블 권선정렬 시스템의 제어에 관한 연구)

  • 양승윤;조상훈;최준호;박래석
    • 제어로봇시스템학회:학술대회논문집
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    • 2000.10a
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    • pp.250-250
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    • 2000
  • The purpose of this paper is to study on the control of a self-activated cable spooling system for towed array handling winch using a hydraulic servo driving unit and a cable position measurement mechanism. To design a controller of the cable spooling system, it is carried out the analysis of the hydraulic servo system and derived the relationship of a parameters through the control theory. Also, it is derived from the control specifications using settling rotation angle and spooling safety ratio proposed to the analysis for the behavior of the system. The cable spooling system is tested and evaluated to validate the performance of the controller.

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A Study on Design and Performance Test for Underwater Towing Sonar Cable (수중 예인 소나용 케이블 설계 및 성능에 대한 연구)

  • Jae-Hyun, Na;Eui-Chang, Hong;Seung-Cheon, Kim;Dong-Gil, Kim
    • The Journal of the Korea institute of electronic communication sciences
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    • v.17 no.6
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    • pp.1095-1104
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    • 2022
  • The towing cable plays a role in dropping and salvaging the Towed Array Sonar System (TASS) into the water and transmitting the signal (information) detected by the sonar in the water to the probe or surface ship. The towing cable consists of a heavy cable and a lightweight cable in detail. The towing cable for sonar is characterized by high reliability and durability as the underwater environment deteriorates as the operating depth increases. Due to these restrictions, cases designed and manufactured in Korea are extremely rare. The core technology for towing cable design secured through this study is expected to be used in various ways in the defense industry and the private sector.