• Title/Summary/Keyword: Sloshing Flow

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Characteristic Analysis of Nonlinear Sloshing in Baffled Tank (격막 설치에 따른 비선형 슬로싱 특성 연구)

  • Lee, Hong-Woo;Cho, Jin-Rae
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.29 no.11 s.242
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    • pp.1455-1462
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    • 2005
  • In this paper, we intend to introduce a nonlinear finite element method based on the fully nonlinear potential flow theory in order to simulate the large amplitude sloshing flow in two-dimensional baffled tank subject to horizontally forced excitation. The free surface is tracked by a direct time differentiation scheme with the four-step predictor-corrector time integration method. The flow velocity is accurately recovered from the velocity potential by second-order least square method. In order to maintain the finite element mesh regularity and total mass, the semi-Lagrangian surface tracking method with area conservation is applied. According to the numerical formulae, we perform the parametric experiments by varying the installation height and the opening width of baffles, in order to examine the effects of baffle on the nonlinear liquid sloshing. From the numerical results, the hydrodynamic characteristics of the large amplitude sloshing are investigated.

DEVELOPMENT OF A NUMERICAL SIMULATION METHOD FOR THE ANALYSIS OF SLOSHING PROBLEMS BASED ON CCUP SCHEME (슬로싱 해석을 위한 CCUP 기반 시뮬레이션 기술 개발)

  • Park, J.C.;Hwang, S.C.;Jeong, S.M.
    • Journal of computational fluids engineering
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    • v.16 no.2
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    • pp.1-10
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    • 2011
  • A new computational program, which is based on the CIP/CCUP(Constraint Interpolation Profile/CIP Combined Unified Procedure) method, has been developed to numerically analyse sloshing phenomena dealt as multiphase-flow problems. For the convection terms of Navier-Stokes equations, the RCIP(Rational function CIP) method was adopted and the THINC-WLIC(Tangent of Hyperbola for Interface Capturing-Weighted Line Interface Calculation) method was used to capture the air/water interface. To validate the present numerical method, two-dimensional dam-breaking and sloshing problems in a rectangular tank were solved by the developed method in a stationary Cartesian grid system. In the case of sloshing problems, simulations by using a improved MPS(Moving Particle Simulation) method, which is named as PNU-MPS(Pusan National University-MPS), were also carried out. The computational results are compared with those of experiments and most of the comparisons are reasonably good.

A Study on Ullage Effect in 2-D Sloshing Experiment (얼리지 압력이 2차원 슬로싱 실험에 미치는 영향에 관한 연구)

  • Choi, Hu-In;Kwon, Sun-Hong;Lee, Sang-Beom;Lee, Ki-Hyun;Park, Jung-Ho
    • Journal of Ocean Engineering and Technology
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    • v.26 no.1
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    • pp.54-59
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    • 2012
  • This study presents investigation on ullage effect in sloshing experiment. The experiment was done with two dimensional tank. Sloshing experiments were carried out in the tank with 6 different ullage pressures. The tested filling ratio was 30% of the tank height. The flow field was recorded with high speed camera. The sloshing impact pressure were measured at 18 locations. It was shown that the variation of ullage pressures influences the magnitude of pressure and flow field. This study demonstrated the importance of ullage pressure in sloshing test.

Sloshing Analysis of a Simple Tank using Fluid-structure Interface Method (유체-구조 연성 방법에 의한 단순 탱크 슬로싱 해석)

  • Kang, Sung-Jong;Seo, Hong-Jae;Kim, Byung-Joo
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.10 no.4
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    • pp.31-37
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    • 2011
  • Fuel tank sloshing noise of vehicle is caused by flow impact on the tank wall during sudden braking, and the sloshing vibration of tank wall is a coupled phenomenon of the fuel inside tank and tank wall structure. Therefore, Fluid-Structure Interface(FSI) analysis technology should be adopted to predict accurately the sloshing vibration. In this study, FSI approach was employed to analyze sloshing phenomenon for a simple tank model with velocity change of the actual vehicle test. First, the simulated results for rigid tank model were compared with those for deformable tank model. Next, influence of baffle location and shape of baffle holes on the acceleration magnitude and the maximum stress of tank wall was investigated. In addition, sloshing analysis for tank with another baffle type was carried out.

A numerical study on sloshing impact loads in prismatic tanks under forced horizontal motion

  • Parthasarathty, Nanjundan;Kim, Hyunjong;Choi, Yoon-Hwan;Lee, Yeon-Won
    • Journal of Advanced Marine Engineering and Technology
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    • v.41 no.2
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    • pp.150-155
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    • 2017
  • Many engineering issues are caused because of sloshing phenomena. Numerical solution methods including the computational fluid dynamics (CFD) technique, are used to analyze these sloshing problems. In this study, a numerical technique was used to analyze sloshing impact loads in a prismatic tank under forced horizontal motion. The volume-of-fraction (VOF) method was adopted to model the sloshing flow. Six cases were used to compare the effects of the natural frequencies of a simple rectangular and prismatic tank, with impact pressure on the prismatic tank wall. This study also investigated the variable pressure loads and sloshing phenomena in prismatic tanks when the frequencies were changed. The results showed that the average of the peak pressure value for ${\omega}^{\prime}1=4.24=4.24$ was 22% higher than that of ${\omega}_1=4.6$.

Free Surface Tracking for the Accurate Time Response Analysis of Nonlinear Liquid Sloshing

  • Cho Jin-Rae;Lee Hong-Woo
    • Journal of Mechanical Science and Technology
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    • v.19 no.7
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    • pp.1517-1525
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    • 2005
  • Liquid sloshing displays the highly nonlinear free surface fluctuation when either the external excitation is of large amplitude or its frequency approaches natural sloshing frequencies. Naturally, the accurate tracking of time-varying free surface configuration becomes a key task for the reliable prediction of the sloshing time-history response. However, the numerical instability and dissipation may occur in the nonlinear sloshing analysis, particularly in the long-time beating simulation, when two simulation parameters, the relative time-increment parameter a and the fluid mesh pattern, are not elaborately chosen. This paper intends to examine the effects of these two parameters on the potential-based nonlinear finite element method introduced for the large amplitude sloshing flow.

A NUMERICAL ANALYSIS OF THE SLOSHING IN A TANK WITH PLATE/POROUS BAFFLES (판형 및 다공형 배플을 포함한 탱크 내 슬로싱에 대한 유동해석)

  • Lee, Sang-Hyuk;Hur, Nahm-Keon
    • 한국전산유체공학회:학술대회논문집
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    • 2009.04a
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    • pp.215-222
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    • 2009
  • In the present study, a numerical analysis on the sloshing in a tank with the harmonic motion was investigated. A VOF method was used for two-phase flows inside the sloshing tank and a source term of the momentum equation was applied for the harmonic motion. This numerical method was verified by comparing its results with the available experimental data. The sloshing in a tank causes the instability of the fluid flows and the fluctuation of the impact pressure on the tank. By these phenomena of the tank sloshing, the sloshing problems such as the failure and the noise of system can be generated. For the reduction of these sloshing problems, the various baffles such as the horizontal/vertical plate baffles and the porous baffles inside the tank are installed. With the installations of these baffles, the characteristics of the liquid behavior in the sloshing tank, the impact pressure on the wall, the amplitude of the free surface near the wall and the sloshing noise were numerically analyzed.

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Numerical Study of Heat Flux and BOG in C-Type Liquefied Hydrogen Tank under Sloshing Excitation at the Saturated State (포화상태에 놓인 C-Type 액체수소 탱크의 슬로싱이 열 유속과 BOG에 미치는 변화의 수치적 분석)

  • Lee, Jin-Ho;Hwang, Se-Yun;Lee, Sung-Je;Lee, Jang Hyun
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.35 no.5
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    • pp.299-308
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    • 2022
  • This study was conducted to predict the tendency for heat exchange and boil-off gas (BOG) in a liquefied hydrogen tank under sloshing excitation. First, athe fluid domain excited by sloshing was modeled using a multiphase-thermal flow domain in which liquid hydrogen and hydrogen gas are in the saturated state. Both the the volume of fluid (VOF) and Eulerian-based multi-phase flow methods were applied to validate the accuracy of the pressure prediction. Second, it was indirectly shown that the fluid velocity prediction could be accurate by comparing the free surface and impact pressure from the computational fluid dynamics with those from the experimental results. Thereafter, the heat ingress from the external convective heat flux was reflected on the outer surfaces of the hydrogen tank. Eulerian-based multiphase-heat flow analysis was performed for a two-dimensional Type-C cylindrical hydrogen tank under rotational sloshing motion, and an inflation technique was applied to transform the fluid domain into a computational grid model. The heat exchange and heat flux in the hydrogen liquid-gas mixture were calculated throughout the analysis,, whereas the mass transfer and vaporization models were excluded to account for the pure heat exchange between the liquid and gas in the saturated state. In addition, forced convective heat transfer by sloshing on the inner wall of the tank was not reflected so that the heat exchange in the multiphase flow of liquid and gas could only be considered. Finally, the effect of sloshing on the amount of heat exchange between liquid and gas hydrogen was discussed. Considering the heat ingress into liquid hydrogen according to the presence/absence of a sloshing excitation, the amount of heat flux and BOG were discussed for each filling ratio.

The pressure distribution on the rectangular and trapezoidal storage tanks' perimeters due to liquid sloshing phenomenon

  • Saghi, Hassan
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.8 no.2
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    • pp.153-168
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    • 2016
  • Sloshing phenomenon is a complicated free surface flow problem that increases the dynamic pressure on the sidewalls and the bottom of the storage tanks. When the storage tanks are partially filled, it is essential to be able to evaluate the fluid dynamic loads on the tank's perimeter. In this paper, a numerical code was developed to determine the pressure distribution on the rectangular and trapezoidal storage tanks' perimeters due to liquid sloshing phenomenon. Assuming the fluid to be inviscid, the Laplace equation and the nonlinear free surface boundary conditions were solved using coupled boundary element - finite element method. The code performance for sloshing modeling was validated using Nakayama and Washizu's results. Finally, this code was used for partially filled rectangular and trapezoidal storage tanks and free surface displacement, pressure distribution and horizontal and vertical forces exerted on the tanks' perimeters due to liquid sloshing phenomenon were estimated and discussed.

Interactions of Faraday Wave and Sloshing Wave Generated in the Strong Nonlinear Sloshing Problem of Rectangular Open Tank (사각용기의 강한 비선형 슬로싱 문제에서 발생하는 페러데이파와 슬로싱파의 상호작용)

  • Park, Jun Sang
    • Journal of the Korean Society of Visualization
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    • v.18 no.3
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    • pp.14-22
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    • 2020
  • An experiment, in the cases that satisfies deep water condition, has been performed to observe the strongly nonlinear sloshing flow in a rectangular tank. A variety of parametric study on oscillating frequency and amplitude was conducted and we found that two types of wave motions, sloshing wave and Faraday wave, could be persisting simultaneously even in horizontal sloshing problem. Moreover, it is observed both of symmetric and skewed symmetric Faraday wave exist. A comprehensive explanation is given to the generation mechanism of those waves and how to interact among them.