Nonlinear Sloshing in a Spherical Tank

Faltinsen, Odd M.; Timokha, Alexander

doi:10.1115/omae2013-10036

Cited by 153 publications

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“…Sloshing model tests with hydroelastic impact require the simultaneous satisfaction of the Froude scaling together with proper scaling of the elastic properties of the structure. 7 Because of the complex structure characterizing a typical panel of a Mark III containment system, its complete structural scaling is an unresolved challenge, which is far from the aims of the present study. According to Faltinsen and Timokha, 7 we must ensure the Froude scaling of the relevant natural frequencies of the elastic vibrations of the structural panel.…”

Section: E Scaling Of the Physical Problemmentioning

confidence: 61%

“…(4) with clamped conditions at the beam ends. Following Faltinsen and Timokha, 7 by defininġ q k φ k the velocity potential associated with the vibrations of mode k, and assuming a proportional model for the structural damping, we get…”

Section: B a Simplified Hydroelastic Approach: The Hybrid Modelmentioning

confidence: 99%

“…In all these cases, when the typical temporal duration of the local load is comparable with a natural period of the structural mode contributing to large structural stresses, hydroelasticity matters, 7 and affects the integrity of the structure. As a consequence, the assessment of the structural strength of a LNG membrane tank exposed to the dynamic and impulsive sloshing loads requires the prediction of the hydroelastic response of the structure.…”

Section: Introductionmentioning

confidence: 99%

“…The sizes, the thickness and the structural properties of the deformable beam have been fixed in order to reproduce the lowest structural natural wet frequency of a prototype panel typically used in a Mark III containment system. 7 Geometric scaling is respected using…”

Section: Introductionmentioning

confidence: 99%

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Hydroelastic slamming response in the evolution of a flip-through event during shallow-liquid sloshing

et al. 2014

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The evolution of a flip-through event [6] upon a vertical, deformable wall during shallow-water sloshing in a 2D tank is analyzed, with specific focus on the role of hydroelasticity. An aluminium plate, whose dimensions are Froude-scaled in order to reproduce the first wet natural frequency associated with the typical structural panel of a Mark III containment system, is used. (Mark III Containment System is a membrane-type tank used in the Liquefied Natural Gas (LNG) carrier to contain the LNG. A typical structural panel is composed by two metallic membranes and two independent thermal insulation layers. The first membrane contains the LNG, the second one ensures redundancy in case of leakage.) Such a system is clamped to a fully rigid vertical wall of the tank at the vertical ends while being kept free on its lateral sides. Hence, in a 2D flow approximation the system can be suitably modelled, as a double-clamped Euler beam, with the Euler beam theory. The hydroelastic effects are assessed by cross-analyzing the experimental data based both on the images recorded by a fast camera, and on the strain measurements along the deformable panel and on the pressure measurements on the rigid wall below the elastic plate. The same experiments are also carried out by substituting the deformable plate with a fully stiff panel. The pressure transducers are mounted at the same positions of the strain gauges used for the deformable plate. The comparison between the results of rigid and elastic case allows to better define the role of hydroelasticity. The analysis has identified three different regimes characterizing the hydroelastic evolution: a quasi-static deformation of the beam (regime I) precedes a strongly hydroelastic behavior (regime II), for which the added mass effects are relevant; finally, the free-vibration phase (regime III) occurs. A hybrid method, combining numerical modelling and experimental data from the tests with fully rigid plate is proposed to examine the hydroelastic effects. Within this approach, the measurements provide the experimental loads acting on the rigid plate, while the numerical solution enables a more detailed analysis, by giving additional information not available from the experimental tests. More in detail, an Euler beam equation is used to model numerically the plate with the added-mass contribution estimated in time. In this way the resulting hybrid method accounts for the variation of the added mass associated with the instantaneous wetted length of the beam, estimated from the experimental images. Moreover, the forcing hydrodynamic load is prescribed by using the experimental pressure distribution measured in the rigid case. The experimental data for the elastic beam are compared with the numerical results of the hybrid model and with those of the standard methods used at the design stage. The comparison against the experimental data shows an overall satisfactory prediction of the hybrid model. The maximum peak pressure predicted by the standard methods agrees with the result of th...

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Section: E Scaling Of the Physical Problemmentioning

confidence: 61%

Section: B a Simplified Hydroelastic Approach: The Hybrid Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Hydroelastic slamming response in the evolution of a flip-through event during shallow-liquid sloshing

et al. 2014

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“…One of them is related to the thermodynamic response inside LNG fuel tanks enhanced by liquid sloshing. Sloshing can be characterized as the motion of liquids in containers or vessels [2]. The rapid pressure drop is related to the movement of the tank, filling depth and the temperature of the bunkered LNG.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulations of Sloshing and the Thermodynamic Response Due to Mixing

Grotle¹,

Æsøy²

2017

Energies

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Abstract:In this paper, we apply computational fluid dynamics (CFD) to study the thermodynamic response enhanced by sloshing inside liquefied natural gas (LNG) fuel tanks. An existing numerical solver provided by OpenFOAM is used to simulate sloshing in a model scaled tank of similar form to an LNG fuel tank. The interface area has been estimated for different sloshing regimes on three different numerical grids representing the tank in 3D. Estimating the interface area is done by performing a grid-independence study. In the most severe sloshing conditions, convergence is not achieved. By combining the results from experiments and CFD, it is found that the interface area and the condensation mass flow rate are in phase for the most severe sloshing condition. The existing CFD solver is modified to determine the pressure drop. The simulation results are compared to the experimental data, and the results are acceptable and thereby show a potential in applying CFD to predict the thermodynamic response due to sloshing. By plotting the temperature contours, indications are found that the exchange of cold bulk and saturated liquid due to sloshing has a significant influence on the thermodynamic response.

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MLPG_R method for modelling 2D flows of two immiscible fluids

Zhou

Yan

2016

Numerical Methods in Fluids

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This is the accepted version of the paper.This version of the publication may differ from the final published version. Permanent repository link City Research OnlineThis article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process which may lead to differences between this version and the Version of Record. Please cite this article as doi: 10.1002/fld.4353This article is protected by copyright. All rights reserved. MLPG_R method for modelling 2D flows of two immiscible fluids AbstractThis is a first attempt to develop the Meshless Local Petrov-Galerkin method with Rankine source solution (MLPG_R method) to simulate multiphase flows. In this paper, we do not only further develop the MLPG_R method to model two-phase flows but also propose two new techniques to tackle the associated challenges. The first technique is to form an equation for pressure on the explicitly identified interface between different phases by considering the continuity of the pressure and the discontinuity of the pressure gradient (i.e., the ratio of pressure gradient to fluid density), the latter reflecting the fact that the normal velocity is continuous across the interface. The second technique is about solving the algebraic equation for pressure, which gives reasonable solution not only for the cases with low density ratio but also for the cases with very high density ratio, such as more than 1000. The numerical tests show that the results of the newly developed two-phase MLPG_R method agree well with analytical solutions and experimental data in the cases studied.The numerical results also demonstrate that the newly developed method has a second-order convergent rate in the cases for sloshing motion with small amplitudes.

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Nonlinear Sloshing in a Spherical Tank

Cited by 153 publications

References 0 publications

Hydroelastic slamming response in the evolution of a flip-through event during shallow-liquid sloshing

Hydroelastic slamming response in the evolution of a flip-through event during shallow-liquid sloshing

Numerical Simulations of Sloshing and the Thermodynamic Response Due to Mixing

MLPG_R method for modelling 2D flows of two immiscible fluids

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