6 research outputs found
Influence of raised invar edges on sloshing impact pressures - Numerical investigations
No full textThis paper presents a numerical investigation of the influence of raised invar edges on wet drop tests pressures. The aim of this study is to evaluate the capabilities of the CFD software Open- FOAM ([6]) to deal with fluid structure impact problems in the context of sloshing inside membrane tanks. More precisely, the objective is to evaluate OpenFOAM capabilities for water drop tests simulations for a smooth wedge on one hand and a wedge equipped with invar edges (like these which equip the Cargo Containment System NO96 produced by GTT) on the other hand, both falling into calm water without inclination. The obtained numerical results are then compared to Wagner's solution for the smooth wedge and to experimental measurements for the wedge with edges presented in ([2]). Numerical simulations are in very good agreement with Wagner's solution and experimental results ([2]) showing the OpenFOAM capability to deal with fluid structure impact problems in the context of sloshing inside membrane tanks. The agreement between numerical and experimental results confirms also that raised invar edges tend to enhance the magnitude of sloshing pressures. This confirmation emphasizes the importance of considering the physics of invar edge effects in defining the design pressure to be used in assessing the integrity of membrane LNG tanks. © 2011 Taylor & Francis Group, London
Influence of raised invar edges on sloshing impact pressures numerical investigations
No full textThis paper presents a numerical investigation of the influence of raised invar edges on wet drop tests pressures. The aim of this study is to evaluate the capabilities of the CFD software OpenFOAM (Ref. [6]) to deal with fluid structure impact problems in the context of sloshing inside membrane tanks. More precisely, the objective is to simulate water drop tests for a smooth wedge on one hand and a wedge equipped with invar edges (like these which equip the Cargo Containment System NO96 produced by GTT) on the other hand, both falling into calm water without inclination. The obtained numerical results are then compared to Wagner's solution for the smooth wedge and to experimental measurements for the wedge with edges presented in (Ref. [2]). Numerical simulations are in very good agreement with Wagner's solution and experimental results (Ref. [2]) showing the OpenFOAM capability to deal with fluid structure impact problems in the context of sloshing inside membrane tanks. The agreement between numerical and experimental results confirms also that raised invar edges tend to enhance the magnitude of sloshing pressures. This confirmation emphasizes the importance of considering the physics of invar edge effects in defining the design pressure to be used in assessing the integrity of membrane LNG tanks. Copyright © 2011 by the International Society of Offshore and Polar Engineers (ISOPE)
Comparison of experimental and numerical sloshing loads in partially filled tanks
No full textSloshing phenomenon consists in the movement of liquids inside partially filled tanks, whichgenerates dynamic loads on the tank structure. Resulting impact pressures are of great importance in assessingstructural strength, and their correct evaluation still represents a challenge for the designer due to the highnonlinearities involved, with complex free surface deformations, violent impact phenomena and influence of airtrapping. In the present paper a set of two-dimensional cases for which experimental results are available areconsidered to assess merits and shortcomings of different numerical methods for sloshing evaluation, namely twocommercial RANS solvers (FLOW-3D and LS-DYNA), and two own developed methods (Smoothed ParticleHydrodynamics and RANS). Impact pressures at different critical locations and global moment induced by watermotion for a partially filled tank with rectangular section having a rolling motion have been evaluated and resultsare compared with experiments
Comparison of experimental and numerical sloshing loads in partially filled tanks.
No full textSloshing describes the movement of liquids inside partially filled tanks, generating dynamic loads on the tank structure. The resulting impact pressures are of great importance in assessing structural strength, and their correct evaluation still represents a challenge for the designer due to the high level of nonlinearities involved, with complex free surface deformations, violent impact phenomena and influence of air trapping. In the present paper, a set of two-dimensional cases, for which experimental
results are available, is considered to assess the merits and shortcomings of different numerical methods for sloshing evaluation, namely two commercial RANS solvers (FLOW-3D and LS-DYNA), and two academic software (Smoothed Particle Hydrodynamics and RANS). Impact pressures at various critical locations and global moment induced by water motion in a partially filled rectangular tank, subject to a simple harmonic rolling motion, are evaluated and predictions are compared with experimental measurements
Comparison of experimental and numerical sloshing loads in partially filled tanks
No full textSloshing phenomenon consists in the movement of liquids inside partially filled tanks, which generates dynamic loads on the tank structure. Resulting impact pressures are of great importance in assessing structural strength, and their correct evaluation still represents a challenge for the designer due to the high nonlinearities involved, with complex free surface deformations, violent impact phenomena and influence of air trapping. In the present paper a set of two-dimensional cases for which experimental results are available are considered to assess merits and shortcomings of different numerical methods for sloshing evaluation, namely two commercial RANS solvers (FLOW-3D and LS-DYNA), and two own developed methods (Smoothed Particle Hydrodynamics and RANS). Impact pressures at different critical locations and global moment induced by water motion for a partially filled tank with rectangular section having a rolling motion have been evaluated and results are compared with experiments
Repeatability and Two-Dimensionality of Model Scale Sloshing Impacts
No full textCanonical test cases for sloshing wave impact problems are pre-sented and discussed. In these cases the experimental setup has been simpli?ed seeking the highest feasible repeatability; a rectangular tank subjected to harmonic roll motion has been the tested con?guration. Both lateral and roof impacts have been studied, since both cases are relevant in sloshing assessment and show speci?c dynamics. An analysis of the impact pressure of the ?rst four impact events is provided in all cases. It has been found that not in all cases a Gaussian ?tting of each individual peak is feasible. The tests have been conducted with both water and oil in order to obtain high and moderate Reynolds number data; the latter may be useful as simpler test cases to assess the capabilities of CFD codes in simulating sloshing impacts. The re-peatability of impact pressure values increases dramatically when using oil. In addition, a study of the two-dimensionality of the problem using a tank con?guration that can be adjusted to 4 di?erent thicknesses has been carried out. Though the kinemat-ics of the free surface does not change signi cantly in some of the cases, the impact pressure values of the ?rst impact events changes substantially from the small to the large aspect ratios thus meaning that attention has to be paid to this issue when reference data is used for validation of 2D and 3D CFD codes
