• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.6
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• pp.796-802
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• 2018

The effects of inner liquid sloshing on vessel motions are a well-known factor. It was investigated experimentally and numerically. In this regard, the study of many efforts to reduce natural phenomena of vessel motions by adopting special devices especially for roll motions. Among many devices, inserting baffles in the inner liquid tank is very common. In this study, one investigated the vessel motions with inner sloshing tanks with baffles inside. For the numerical simulation, one employed a dynamically coupled program between boundary-element-method-based vessel motion analysis program and a particle-based computational fluid dynamics program. Comparing corresponding experimental results validated the dynamically coupled program. The validated coupled program was used to simulate vessel motions, including sloshing effects with various lengths of inner baffles. The simulation results show that not only the filling ratio of inner liquid, but also the length of clearance due to baffles influenced the vessel motions. The significant point of this study was that the natural frequency of vessel motions can be maintained irrespective of the amount of filling ratio through adjustment of the clearance. In a future study, the effects of various numbers of baffles with various clearances would be conducted to percuss the possibility of vessel motion control with inner liquid sloshing effects.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.172-175
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• 2002

Sloshing of fuel in a liquid propellant tank is an important part of the dynamic and the stability analysis of the rocket. Baffles are installed in a propellant tank to reduce the instability due to sloshing. Multi degree of spring-mass-damper model was used to model sloshing of fuel in an axisymmetric tank. The natural frequencies and damping ratios are estimated. In order to verify the estimated natural frequencies and damping ratios, tests are performed for the real propellant tank of KSR-III with single ring baffle. Results of fuel sloshing analysis are compared with those of tests.

• Journal of Ocean Engineering and Technology
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• v.8 no.2
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• pp.93-104
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• 1994

Recently in the design of super tankers or LNG carriers which transport a large amount of liquid in the cargo holds, the structural damage due to liquid sloshing becomes an important problem. The impact pressure from sloshing is most violent when the liquid motion of a partially filled tank is in resonance with the motion of a ship. In this paper the sloshing natural periods in liquid cargo tanks are estimated for partially filled tanks with various geometries. Especially the sloshing periods of baffled tanks which are often installed to reduce liquid motion and sloshing forces are calculated. A variational method is adopted to analyze the baffled tank of arbitrary filling depth of liquid. In this approach the liquid domain is divided into several subdomains in which the analytic solutions are potential energy are calculated from the velocity potentials in eachsubdomain. By minimizing the Hamilton's functional, the sloshing natural periods are estimated and the results are compared with experimental and numerical results.

• Journal of Advanced Research in Ocean Engineering
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• v.3 no.3
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• pp.149-157
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• 2017

Since sloshing effects influences ship motions including floater's natural frequencies. The significant factors changing ship motions are inner liquid impact loads and inertia forces and moments with respect to its filling ratio. This means that changing sloshing loads with sloshing effects reduction device (SERD) may control ship motions. In this regard, conceptual model for adjustable SERD was suggested by authors and then implanted into fully coupled program between vessel motion and sloshing. By changing clearances of baffles in the inner tank which were component of SERD, then the roll RAOs from each case were obtained. It is revealed that using well-controlled SERD can maintain natural frequencies of floater even inner tank has different filling ratio.

• 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.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.9
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• pp.1018-1024
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• 2011

Liquid sloshing occurs when a partially filled liquid tank is subjected to undesirable external forces or acceleration/deceleration for positioning control. Installation of baffles is still the most popular way to suppress the sloshing, but recent successes of input shaping in reducing structural vibrations may give a possible alternative. We aim at investigating the applicability of input shaping to sloshing suppression by numerically solving fluid motions in a rectangular tank. The tank is partially filled with water and it is suddenly put into a sequence of horizontal motions of acceleration and constant speed. The flow is assumed to be two-dimensional, incompressible, and in viscid, and a VOF two-phase model is used to capture the free surface. Results show that the sloshing can be successfully suppressed by shaping the input, i.e., the velocity or acceleration profile of tank. Three different input shapers (ZII, ZVD, and two-mode convolved ZV shapers) are tested and compared in this study Among them, the convolved ZV shaper shows a best performance to eliminate the sloshing almost completely.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.9
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• pp.950-959
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• 2009

Liquid fluctuation called sloshing within liquid-storage tank gives rise to the significant effect on the dynamic stability of tank. This liquid sloshing can be effectively suppressed by installing baffles within the tank, and the suppression effect depends strongly on the design parameters of baffle like the baffle configuration. The present study is concerned with the parametric evaluation of the sloshing suppression effect for the CNG-storage tank, a next generation liquefied fuel for vehicles, to the major design parameters of baffle, such as the baffle configuration, the installation angle and height, the hole size of baffle. The coupled FEM-FVM analysis was employed to effectively reflect the interaction between the interior liquid flow and the tank elastic deformation.

• 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.

• 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.

• 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.