• Title/Summary/Keyword: Sloshing Flow

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Numerical Analysis on Nonlinear Sloshing Problem using Finite Element Method (유한 요소법을 이용한 비선형 슬러싱 문제 해석)

  • Kyoung Jo-Hyun;Kim Jang-Whan;Cho Seok-Kyu;Bai Kwang-June
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.7 no.4
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    • pp.216-223
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    • 2004
  • A nonlinear sloshing problem is numerically simulated. During excessive sloshing the sloshinginduced impact load can cause a critical damage on the tank structure. A three-dimensional free-surface flow in a tank is formulated in the scope of potential flow theory. The exact nonlinear free-surface condition is satisfied numerically. A finite-element method based on Hamiltons principle is employed as a numerical scheme. The problem is treated as an initial-value problem. The computations are made through an iterative method at each time step. The hydrodynamic loading on the pillar in the tank is computed.

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A Numerical Study on the Sloshing Characteristics in a Two-dimensional Rectangular Tank Using the Level Set Method (레벨셋법을 이용한 2 차원 사각 탱크 내부의 슬로싱 특성에 관한 수치적 연구)

  • Yoon, Hyun-Sik;Lee, Jung-Min;Chun, Hwan-Ho;Lee, Hyun-Goo
    • Journal of the Society of Naval Architects of Korea
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    • v.45 no.2
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    • pp.132-143
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    • 2008
  • The sloshing phenomena in a two-dimensional rectangular tank are investigated using a level set method based on finite volume method. The code validations are performed by comparing between the present results and previous numerical results, which gives a good agreement. We present the streamlines pattern, free surface shape, maximum free surface elevation and pressure fluctuation patterns in the tank under the pitch and surge motions with various frequencies. These two different motions cause the different flow structures in the tank. The time variations of surface elevation and pressure at the different locations in the tank strongly depend on the exciting frequency of tank moving.

Analysis of Sloshing Frequency Response in Rectangular Fuel-Storage Tank (사각형 연료탱크 내 슬로싱 주파수 응답 해석)

  • 조진래;이홍우;하세윤;박태학;이우용
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.16 no.1
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    • pp.95-104
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    • 2003
  • This paper deals with the analytic and FEM analyses of sloshing frequency response of incompressible, invicid and irrotational flow in two dimensional rectangular tank. We use Laplace equation based on potential theory as governing equation. For small amplitude sloshing motion, the linearized free surface condition was applied and the analytic solution as obtained by the separation of variables. To simulate the effect of the energy dissipation due to viscous damping, artificial viscous coefficient is introduced and the divergence of response at resonance frequencies may be avoided by this coefficient. This problem was solved by FEM using 9-node elements in order to predict the maximum amplitude of sloshing response. Numerical results of free surface height, fluid pressure and fluid force show good agreement with those by analytic solution. After verifying the test FEM program, we analyze the frequency response characteristics of sloshing to the fluid height.

Dynamic Response Analysis of Nonlinear Sloshing in Two Dimensional Rectangular Tank using Finite Element Method (유한요소법을 이용한 2차원 사각탱크내 비선형 슬로싱 동응답 해석)

  • 조진래;이홍우;하세윤;박태학;이우용
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.16 no.1
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    • pp.33-42
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    • 2003
  • This paper deals with the FEM analysis of nonlinear sloshing of incompressible, invicid and irrotational flow in two dimensional rectangular tank. We use laplace equation based on potential theory as governing equation. For large amplitude sloshing motion, kinematic and dynamic free surface conditions derived from Bernoulli equation are applied. This problem is solved by FEM using 9-node elements. For the time integration and accurate velocity calculation, we introduce predictor-corrector time marching scheme and least square method. Also, numerical stability in tracking of free surface is obtained by direct calculation of free surface location to time variation. Numerical results of sloshing induced by harmonic excitations, while comparing with those of linear theory and references, prove the accuracy and stability. After verification of our program, we analyze sloshing response characteristics to the fluid height and the excitation amplitude.

Knowledge from recent investigations on sloshing motion in a liquid pool with solid particles for severe accident analyses of sodium-cooled fast reactor

  • Xu, Ruicong;Cheng, Songbai;Li, Shuo;Cheng, Hui
    • Nuclear Engineering and Technology
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    • v.54 no.2
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    • pp.589-600
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    • 2022
  • Investigations on the molten-pool sloshing behavior are of essential value for improving nuclear safety evaluation of Core Disruptive Accidents (CDA) that would be possibly encountered for Sodium-cooled Fast Reactors (SFR). This paper is aimed at synthesizing the knowledge from our recent studies on molten-pool sloshing behavior with solid particles conducted at the Sun Yat-sen University. To better visualize and clarify the mechanism and characteristics of sloshing induced by local Fuel-Coolant Interaction (FCI), experiments were performed with various parameters by injecting nitrogen gas into a 2-dimensional liquid pool with accumulated solid particles. It was confirmed that under different particle-bed conditions, three representative flow regimes (i.e. the bubble-impulsion dominant, transitional and bed-inertia dominant regimes) are identifiable. Aimed at predicting the regime transitions during sloshing process, a predictive empirical model along with a regime map was proposed on the basis of experiments using single-sized spherical solid particles, and then was extended for covering more complex particle conditions (e.g. non-spherical, mixed-sized and mixed-density spherical particle conditions). To obtain more comprehensive understandings and verify the applicability and reliability of the predictive model under more realistic conditions (e.g. large-scale 3-dimensional condition), further experimental and modeling studies are also being prepared under other more complicated actual conditions.

Sloshing Flows in Ship Tanks

  • Kim, Yonghwan;Shin, Yung-Sup
    • Journal of Ship and Ocean Technology
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    • v.4 no.3
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    • pp.21-32
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    • 2000
  • In the present paper, the sloshing flow in the liquid holds of a large tanker is simulated using a numerical method. In the fluid domain, the three-dimensional Navier-Stokes equation with free surface is solved using a finite difference method, and the realistic shapes of multi holds are modeled including the internal members. The time-history of the tank motion is obtained using a time-domain program for ship motion. In order to computer the impulsive pressures on internal structures, a concept of buffer zone is adopted near the tank ceiling during impact occurrence. This study demonstrates that the global fluid motion in the multi liquid holds of ships and FPSO's can be simulated using the numerical method and the corresponding local pressure can be predicted with reasonable accuracy.

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Measurements on a Ship's Sloshing Flows by PIV (PIV에 의한 선박 슬로싱 유동 측정해석)

  • Doh, Deog-Hee;Cho, Yong-Beom;Pyeon, Yong-Beom;Baek, Tae-Sil;Kwon, Soon-Hong;Lee, Jeong-Han;Hwang, Yoon-Sik;Ryu, Min-Cheol
    • 한국가시화정보학회:학술대회논문집
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    • 2007.11a
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    • pp.119-122
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    • 2007
  • The sloshing flows in the cargo tank model of a ship are measured by PIV and are analyzed with the results. The measurement system is consisted of a Nd-Yag laser(120mJ, 15Hz). two cameras($1k\;{\times}\;1k$) and a host computer. Four experimental cases were tested for the tank model. in which swaying motions are made by 6 DOF-motion platform. The amplitudes of swaying are 9.76mm and 29.29mm, and the frequencies are 0.633Hz and 0.828Hz. The measurement regions are the vertical plane 50mm away from the front wall of the tank where a pump tower is installed. It was verified that the flow patterns of the sloshing are similar each other when the swaying amplitudes are similar.

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Effect of Chamfering Top Corners on Liquid Sloshing in the Three-dimensional Rectangular Tank (챔퍼가 3차원 사각 탱크 내부의 액체 슬로싱에 미치는 영향)

  • Jung, Jae-Hwan;Lee, Chang-Yeol;Yoon, Hyun-Sik
    • Journal of the Society of Naval Architects of Korea
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    • v.47 no.4
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    • pp.508-516
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    • 2010
  • This study aims at investigating the effect of the chamfer on the liquid sloshing in the three-dimensional (3D) rectangular tank. In order to simulate the 3D incompressible viscous two-phase flow in the 3D tank with partially filled liquid, the present study has adopted the volume of fluid (VOF) method based on the finitevolume method which has been well verified by comparing with the results of the relevant previous researches. The effects of the chamfering top corners of the tank on the liquid sloshing characteristics have been investigated. The angle of the chamfering top corners (${\theta}$) has been changed in the range of $0^{\circ}{\leq}{\theta}{\leq}60^{\circ}$(${\Delta}{\theta}=15^{\circ}$) to observe the free surface behavior, and the effect on wall impact load. Generally, as the angle of the chamfering top corners increases, the impact pressure on the upper knuckle point decreases. However it seemed that a critical angle of the chamfering top corners exists to reveal the lowest impact pressure on the wall.

Fluid Structure Interaction Analysis of Membrane Type LNG CCS Experiencing the Sloshing Impact by Impinging Jet Model (멤브레인형 LNG 화물창의 강도평가를 위해 적용된 분사모델을 이용한 유체구조 연성해석에 관한 연구)

  • Hwang, Se Yun;Lee, Jang Hyun
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.28 no.1
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    • pp.71-78
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    • 2015
  • The reliable sloshing assessment methods for LNG CCS(cargo containment system) are important to satisfy the structural strength of the systems. Multiphase fluid flow of LNG and Gas Compressibility may have a large effect on excited pressures and structural response. Impinging jet model has been introduced to simulate the impact of the LNG sloshing and analyze structural response of LNG CCS as a practical FSI(fluid structure interaction) method. The practical method based on fluid structure interaction analysis is employed in order to evaluate the structural strength in actual scale for Mark III CCS. The numerical model is based on an Euler model that employs the CVFEM(control volume based finite element method). It includes the particle motion of gas to simulate not only the interphase interaction between LNG liquid and gas and the impact load on the LNG insulation box. The analysis results by proposed method are evaluated and discussed for an effectiveness of FSI analysis method.

Adaptive fluid-structure interaction simulation of large-scale complex liquid containment with two-phase flow

  • Park, Sung-Woo;Cho, Jin-Rae
    • Structural Engineering and Mechanics
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    • v.41 no.4
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    • pp.559-573
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    • 2012
  • An adaptive modeling and simulation technique is introduced for the effective and reliable fluid-structure interaction analysis using MSC/Dytran for large-scale complex pressurized liquid containment. The proposed method is composed of a series of the global rigid sloshing analysis and the locally detailed fluid-structure analysis. The critical time at which the system exhibits the severe liquid sloshing response is sought through the former analysis, while the fluid-structure interaction in the local region of interest at the critical time is analyzed by the latter analysis. Differing from the global coarse model, the local fine model considers not only the complex geometry and flexibility of structure but the effect of internal pressure. The locally detailed FSI problem is solved in terms of multi-material volume fractions and the flow and pressure fields obtained by the global analysis at the critical time are specified as the initial conditions. An in-house program for mapping the global analysis results onto the fine-scale local FSI model is developed. The validity and effectiveness of the proposed method are verified through an illustrative numerical experiment.