• Title/Summary/Keyword: MPS법

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Prediction of Oil Amount Leaked from Damaged Tank Using 2-dimensional Particle Simulation (파손된 탱크의 기름 유출량 산정을 위한 2차원 입자법 시뮬레이션)

  • Nam, J.W.;Hwang, S.C.;Park, J.C.;Kim, M.H.
    • 한국전산유체공학회:학술대회논문집
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    • 2011.05a
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    • pp.278-285
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    • 2011
  • In the present study, the numerical prediction of the oil amount leaked from the hole of a damaged tank is investigated using the improved MPS (Moving Particle Semi-implicit) method, which was originally proposed by Koshizuka and Oka (1996) for incompressible flow. The governing equations, which consist of the continuity and Navier-Stokes equations, are solved by Lagrangian moving particles, and all terms expressed by differential operators should be replaced by the particle interaction models based on a Kernel function. The simulation results are validated though the comparison with the analytic solution based on Torricelli's equilibrium relation. Furthermore, a series of numerical simulations under the various conditions are performed in order to estimate more accurately the initial amount of leaked oil.

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Particle-based Simulation for Sloshing in a Rectangular Tank (사각 탱크 내 슬로싱 해석을 위한 입자법 시뮬레이션)

  • Hwang, Sung-Chul;Lee, Byung-Hyuk;Park, Jong-Chun;Sung, Hong-Gun
    • Journal of Ocean Engineering and Technology
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    • v.24 no.5
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    • pp.31-38
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    • 2010
  • The Floating storage and re-gasification unit (FSRU), which has large cargo storage tanks, is a floating liquefied natural gas (LNG) import terminal. The sloshing motion in tanks that are partially filled with LNG can cause impact pressure on the containment system and affect the global motion of the FSRU. Therefore, the accurate prediction of sloshing motion has been a significant issue in the offshore gas production industry. In this paper, a particle method based on the moving particle semi-implicit (MPS) method proposed by Koshizuka and Oka (1996) has been modified to predict sloshing motion accurately in a rectangular tank with the filling ratio of water. The simulation results, including the violent sloshing of the fluid, were validated by comparison with the original MPS method.

Two-Dimensional Particle Simulation for Behaviors of Floating Body near Quaywall during Tsunami (지진해일 중 해안안벽 주변의 부유체 거동에 관한 2차원 입자법 시뮬레이션)

  • Park, Ji-In;Park, Jong-Chun;Hwang, Sung-Chul;Heo, Jae-Kyung
    • Journal of Ocean Engineering and Technology
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    • v.28 no.1
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    • pp.12-19
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    • 2014
  • Tsunamis are ocean waves generated by movements of the Earth's crust. Several geophysical events can lead to this kind of catastrophe: earthquakes, landslides, volcanic eruptions, and other mechanisms such as underwater explosions. Most of the damage associated with tsunamis are related to their run-up onto the shoreline. Therefore, effectively predicting the run-up process is an important aspect of any seismic sea wave mitigation effort. In this paper, a numerical simulation of the behaviors of a floating body near a quaywall during a tsunami is conducted by using a particle method. First, a solitary wave traveling over shallow water with a slope is numerically simulated, and the results are compared with experiments and other numerical results. Then, the behaviors of floating bodies with different drafts are investigated numerically.

Development of Particle Simulation Method for Analysis of Fluid-Structure Interaction Problems (유체-구조 상호연성 해석을 위한 입자법 시뮬레이션 기술 개발)

  • Hwang, Sung-Chul;Park, Jong-Chun;Song, Chang-Yong;Kim, Young-Hun
    • Journal of Ocean Engineering and Technology
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    • v.27 no.2
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    • pp.53-58
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    • 2013
  • Recently, some fluid-structure interaction (FSI) problems involving the fluid impact loads interacting with structures, such as sloshing, slamming, green-water, etc., have been considered, especially in the ocean engineering field. The governing equations for both an elastic solid model and flow model were originally derived from similar continuum mechanics principles. In this study, an elastic model based on a particle method, the MPS method, was developed for simulating the FSI problems. The developed model was first applied to a simple cantilever deflection problem for verification. Then, the model was coupled with the fluid flow model, the PNU (Pusan National University modified)-MPS method, and applied to the numerical investigation of the coupling effects between a cantilever and a mass of water, which has variable density, free-falling to the end of the cantilever.

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.

Model for Flow Analysis of Fresh Concrete Using Particle Method with Visco-Plastic Flow Formulation (점소성 유동 입자법에 의한 굳지 않은 콘크리트의 유동해석 모델)

  • Cho, Chang-Geun;Kim, Wha-Jung;Choi, Yeol
    • Journal of the Korea Concrete Institute
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    • v.20 no.3
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    • pp.317-323
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    • 2008
  • In the current study, A model for the flow analysis of fresh and highly flowable concrete has been developed using a particle method, the moving particle semi-implicit (MPS) method. The phenomena on the flow of concrete has been considered as a visco-plastic flow problem, and the basic governing equation of concrete particle dynamics has been based on the Navier-Stokes equation in Lagrangian form and the conservation of mass. In order to formulate a visco-plastic flow constitutive law of fresh concrete, concrete is modeled as a highly viscous material in the state of non-flow and as a visco-plastic material in the state of flow after reaching the yield stress of fresh concrete. A flow test of fresh concrete in the L-box was simulated and the predicted flow was well matched with the experimental result. The developed method was well showed the flow motion of concrete particles because it was formulated to be based on the motion of visco-plastic fluid dynamics.

2-Dimensional Moving Particle Simulation for Prediction of Oil Boom Performance in Waves (파랑 중 오일붐 성능 예측을 위한 2차원 입자법 시뮬레이션)

  • Nam, Jung-Woo;Park, Ji-In;Hwang, Sung-Chul;Park, Jong-Chun;Jeong, Se-Min
    • Journal of Ocean Engineering and Technology
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    • v.27 no.4
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    • pp.90-97
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    • 2013
  • Oil booms are one of the most widely used types of equipment for the protection of coastal areas against oil spills. In some situations, however, there are several types of oil leaks from the oil boom. Important factors regarding these phenomena include the surrounding ocean environment, such as waves, the density and viscosity of oil, the length of the oil boom skirt, etc. To estimate the performance of the oil boom, it is necessary to predict the behavior of the spilled oil and oil boom. In the present study, the prediction of oil boom performance in waves was carried out using the Pusan-National-University-modified Moving Particle Semi-implicit (PNU-MPS) method, which is an improved version of the original MPS proposed by Koshizuka and Oka (1996). The governing equations, which consist of continuity and Navier-Stokes equations, are solved by Lagrangian moving particles, and all terms expressed by differential operators in the governing equations are replaced by the particle interaction models based on a kernel function. The simulation results were validated through a comparison with the results of Violeau et al. (2007)..