• Title/Summary/Keyword: sloshing

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Effect on Vessel Motion Caused by Mitigation of Sloshing Impact Loads using Floaters (플로터를 이용한 슬로싱 충격하중 저감효과가 선체운동에 미치는 영향)

  • Nam, Jung-Woo;Kim, Kyung-Sung;Hwang, Sung-Chul;Heo, Jae-Kyung;Park, Jong-Chun;Kim, Moo-Hyun
    • Journal of Ocean Engineering and Technology
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    • v.26 no.4
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    • pp.50-56
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    • 2012
  • When a liquid cargo tank is partially filled with fluid, internal impact loads can be occurred from the vessel's motions. In this study, liquid sloshing problems with a thin top layer of particles with a lighter density than water and the coupling effects of the liquid-sloshing/vessel-motion were investigated in order to reduce the sloshing-induced impact loads. The PNU-MPS (Pusan-National-University-modified Moving Particle Simulation) method for solving the liquid motion inside a tank and the CHARM3D BEM (Boundary Element Method) based time-domain ship motion analysis program for vessel-motion simulation were coupled. From the simulation results, we could see that the floaters seemed to be quite effective at reducing the sloshing impact loads in the case of tank-only sloshing problems, but not as much for the coupling problem with vessel motion.

A Study on the Reduction of the Sloshing of Storage Tank Using Wing and Diaphragm Baffle (날개형 및 격막형 배플을 이용한 유체저장탱크 내부의 슬로싱 저감 연구)

  • Lee, Young-Shin;Kim, Hyun-Soo;Lee, Jae-Hyung;Kim, Young-Wann;Ko, Sung-Ho
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.27 no.12
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    • pp.2039-2046
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    • 2003
  • Storage tank filled with fluid has unique dynamic characteristics compared to general structures, due to the interaction between fluid and structure. The oscillation of the fluid surface caused by external forces is called sloshing, which occurs in moving vehicles with contained liquid masses, such as trucks, railroad cars, aircrafts, and liquid missles. In this study, the evaluation method for the reduction of sloshing, the optimized size and location of wing and diaphragm baffles are suggested based on the experimental results. The experimental device can simulate the translation motion. A rectangular tank and various baffles are fabricated to study on the sloshing characteristics. The forces measured using the load cell at tank wall and those are compared with each other through the Fourier transformation for various conditions. The study of the sloshing of the rectangular tank equipped with baffles is conducted under the same conditions with non-baffled rectangular tank experiment. From the experimental results, the sloshing reduction effect by the baffles is observed. In conclusion in case of diaphragm baffles, the optimized size ratio of the width of baffle to the water height is 0.44 and the installation location has no effect to the damping of sloshing. In case of wing baffles, the optimized size ratio of the width of baffle to the length of a rectangular tank is 0.1 and the optimized location ratio of the baffle to the water height is 0.9.

Rapid response calculation of LNG cargo containment system under sloshing load using wavelet transformation

  • Kim, Yooil
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.5 no.2
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    • pp.227-245
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    • 2013
  • Reliable strength assessment of the Liquefied Natural Gas (LNG) cargo containment system under the sloshing impact load is very difficult task due to the complexity of the physics involved in, both in terms of the hydrodynamics and structural mechanics. Out of all those complexities, the proper selection of the design sloshing load which is applied to the structural model of the LNG cargo containment system, is one of the most challenging one due to its inherent randomness as well as the statistical analysis which is tightly linked to the design sloshing load selection. In this study, the response based strength assessment procedure of LNG cargo containment system has been developed and proposed as an alternative design methodology. Sloshing pressure time history, measured from the model test, is decomposed into wavelet basis function targeting the minimization of the number of the basis function together with the maximization of the numerical efficiency. Then the response of the structure is obtained using the finite element method under each wavelet basis function of different scale. Finally, the response of the structure under entire sloshing impact time history is rapidly calculated by synthesizing the structural response under wavelet basis function. Through this analysis, more realistic response of the system under sloshing impact pressure can be obtained without missing the details of pressure time history such as rising pattern, oscillation due to air entrapment and decay pattern and so on. The strength assessment of the cargo containment system is then performed based on the statistical analysis of the stress peaks selected out of the obtained stress time history.

Simulation of Membrane Sloshing Tank by Using MPS (입자법을 이용한 멤브레인 타입 슬로싱 시뮬레이션)

  • Kim, Kyung Sung
    • Journal of the Korea Convergence Society
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    • v.10 no.10
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    • pp.117-122
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    • 2019
  • In the field of fluid dynamics, the sloshing effects are most common and significant problem. It is usually appeared in the tank filled with fluid which is on the main structure, thus, sloshing effects and its impact load may affect to entire system. For the sloshing effects analysis, impact loads due to tank motion is generally investigated theocratically, experimentally and numerically. The difficulty of sloshing phenomenon is non-linearity induced by large deformation at the free-surface. In this regard, it is well known issue that the repeatability on the sloshing problems is very low. In this study, moving particle semi-implicit method was employed to simulate sloshing problem and then the results were compared with corresponding experiments captured by high accuracy high speed camera. The results from numerical simulation was compared to experimental results.

Computational Fluid Dynamics Study on Two-Dimensional Sloshing in Rectangular Tank (사각형 탱크 내에서의 2차원 슬로싱에 대한 전산유체 역학적 연구)

  • Kwack, Young-Kyun;Ko, Sung-Ho
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.27 no.8
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    • pp.1142-1149
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    • 2003
  • The present study describes a numerical analysis for simulation of the sloshing of flows with free-surface which contained in a rectangular tank moving in harmonic or pitching motion. The VOF function, representing the volume fraction of a cell occupied by the fluid, is calculated for each cells, which gives the location of the free-surface filling any some fraction of cells with fluid. The time-dependent changes of free-surface height are used for visualization subject to several conditions such as fluid height, horizontal acceleration, sinusoidal motion, and viscosity. The free-surface heights were used for comparing wall-force, which is caused by sloshing of flows. Damping effects by baffles were extensively investigated for various conditions in terms of baffle shape and position.

EFFECT OF THE BOUNDARY CONDITION OF REDISTANCE EQUATION ON THE LEVEL SET SOLUTION OF SLOSHING PROBLEM (Redistance 방정식의 경계조건이 슬로싱 문제의 level set 해석에 미치는 영향)

  • Choi, H.G.
    • 한국전산유체공학회:학술대회논문집
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    • 2009.04a
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    • pp.165-169
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    • 2009
  • The effect of the Dirichlet boundary condition for the redistance equation of level set method on the solutionof sloshing problem is investigated by adopting four Dirichlet boundary conditions. For the solution of the incompressible Navier-Stokes equations, P1P1 four-step fractional finite element method is employed and a least-square finite element method is used for the solutions of the two hyperbolic type equations of level set method; advection and redistance equation. ALE (Arbitrary Lagrangian Eulerian) method is used to deal with a moving computational domain. It has been shown that the free surface motion in a sloshing tank is strongly dependent on the type of the Dirichlet boundary condition and the results of broken dam and sloshing problems using various Dirichlet boundary conditions are discussed and compared with the existing experimental results.

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Evaluation for Sloshing Behaviors of Liquid Storage Tank (액체연료탱크의 슬로싱 거동 평가기법)

  • 윤성호;박기진;심국상
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.05a
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    • pp.314-317
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    • 2002
  • The sloshing phenomenon sometimes happens to be occurred in the liquid storage tank due to the unexpected and/or inevitable vibrating conditions and may result in severe effects on the structural stability. This study deals with the development of experimental techniques for the evaluation of sloshing behavior in the liquid storage tank and for the identification of natural frequencies and mode shapes by varying with various vibrating conditions. In addition, suitable method is suggested to minimize the sloshing effect on the liquid storage tank and its validity is experimentally investigate d.

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Evolutionary Optimization Design Technique for Control of Solid-Fluid Coupled Force (고체-유체 연성력 제어를 위한 진화적 최적설계)

  • Kim H.S.;Lee Y.S.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.06a
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    • pp.503-506
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    • 2005
  • In this study, optimization design technique for control of solid-fluid coupled force (sloshing) using evolutionary method is suggested. Artificial neural networks(ANN) and genetic algorithm(GA) is employed as evolutionary optimization method. The ANN is used to analysis of the sloshing and the genetic algorithm is adopted as an optimization algorithm. In the creation of ANN learning data, the design of experiments is adopted to higher performance of the ANN learning using minimum learning data and ALE(Arbitrary Lagrangian Eulerian) numerical method is used to obtain the sloshing analysis results. The proposed optimization technique is applied to the minimization of sloshing of the water in the tank lorry with baffles under 2 second lane change.

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Energy dissipation by particle sloshing in a rolling cylindrical vessel (분체슬로싱 현상에 의한 원통형 용기에서의 에너지 소실)

  • Lee, Soo-Hyuk;Heo, Sung-Mo;Cho, Hye-Min;Son, Hyunsung;Jeong, Seong-Min;Park, Junyoung
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.9 no.3
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    • pp.62-68
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    • 2010
  • In the engineering field, sloshing in rolling vessel is a hot issue because of the connection with ship stability problem. The sloshing phenomena also can be utilized in the field of structure or facility vibration damper. This paper explores the possibility which sloshing of multi-particles can be used to dissipate energy in a rolling container. This energy dissipation can be utilized to the application of rotating damper. Some of the parameters expected to dissipates energy, such as vessel size, particle size, mass fraction and ramp height, have been experimentally and theoretically studied.

Sloshing of liquids in partially filled tanks - a review of experimental investigations

  • Eswaran, M.;Saha, Ujjwal K.
    • Ocean Systems Engineering
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    • v.1 no.2
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    • pp.131-155
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    • 2011
  • Liquid sloshing constitutes a broad class of problems of great practical importance with regard to the safety of liquid transportation systems, such as tank trucks on highways, liquid tank carriages on rail roads, ocean going vessels and propellant tanks in liquid rocket engines. The present work attempts to give a review of some selected experimental investigations carried out during the last couple of decades. This paper highlights the various parameters attributed to the cause of sloshing followed by effects of baffles, tank inclination, magnetic field, tuned liquid dampers, electric field etc. Further, recent developments in the study of sloshing in micro and zero gravity fields have also been reported. In view of this, fifteen research articles have been carefully chosen, and the work reported therein has been addressed and discussed. The key issues and findings have been compared, tabulated and summarized.