Numerical simulation of impact loads using a particle method

SUMMARYIn the present paper, a direct forcing/fictitious domain (DF/FD)–level set method is proposed to simulate the twophase flow–body interaction. The DF/FD does not sacrifice accuracy and robustness by employing a discrete δ (Dirac delta) function to transfer quantities between the Eulerian nodes and Lagrangian points explicitly as the immersed boundary method. The advantages of this approach are the simple concept, the easy implementation and the utilization of original governing equation without modification. The main idea is to combine DF/FD method with the level set method in the Cartesian coordinates. We present the results of a number of test cases to illustrate the effectiveness of the proposed method for single‐phase flow–body interaction problem and the two‐phase flows with a stationary body. Eventually, the simulations of various water entry problems have been conducted to validate the capability and the accuracy of the present method on solving the twophase flow–body interaction. Consequently, the present results are found to be in good agreement with those of previous studies. Copyright © 2013 John Wiley & Sons, Ltd.

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“…and the numerical results of Lee et al . . However, when α < 1°, the numerical results of the present study and that of Lee et al .…”

Section: Resultscontrasting

confidence: 64%

“…and the numerical results of Lee et al . . Dimensions of plate are the same as the experiment of Chung et al .…”

Section: Resultsmentioning

confidence: 99%

Simulation of two‐phase flow–body interaction problems using direct forcing/fictitious domain–level set method

Yoon

Jeon

Jung

et al. 2013

Numerical Methods in Fluids

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“…Khayyer and Gotoh [9] introduce a pressure gradient force vector term that is derived in a momentum conservative form, but it is difficult to implement and requires more computation time, as stated by Tsuruta et al [19]. The stability observed in the pressure gradient force vector term of Khayyer and Gotoh [9] depends on an artificial repulsive force that is predominant over the original pressure gradient force, Equation (4). From the latter, the gradient operators and consequently the pressure gradient force vector term may result in overestimating the interparticle pressure forces and, with this, bring unphysical fluid motions and perturbations [19].…”

Section: Stabilizer Pressure Gradient Force Vector Termmentioning

confidence: 99%

“…These modifications made by artificial pressure terms in some cases give an overvalued magnitude that is not physical and in other cases do not pay attention to the correct direction that the pressure gradient should have (Figure 3(c)). To clarify the differences between the definition of a gradient by Koshizuka and Oka [1], Equation (4), and the definition of the modified pressure gradient by Koshizuka et al [2], Equation (6), the conceptual pictures can be observed in Figures 2(b) and 3(b), for the pressure field distributions in Figures 2(a) and 3(a), respectively. From these figures, we can observe how the modified pressure gradient force vector term of Koshizuka et al [2], Equation (6), in Figure 3(c) changes its magnitude and direction from the pressure gradient force vector term in Figure 2(c) and does not guarantee an effective repulsion of all particles.…”

Section: Stabilizer Pressure Gradient Force Vector Termmentioning

confidence: 99%

On the stabilization of unphysical pressure oscillations in MPS method simulations

Sanchez-Mondragon

2016

Numerical Methods in Fluids

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SUMMARYIn this paper, pressure stability through the suppression of high-frequency pressure oscillations in the moving particle semi-implicit (MPS) method is presented. To obtain a stable pressure field, we improve the freesurface particle search algorithm. Pressure stability follows from the suppression of high-frequency pressure oscillations due to a correction in the Laplacian operator of the Poisson pressure equation and from the correction of the pressure gradient operator. The three proposed modifications are applied gradually and compared with the MPS method to show the improvements in the hydrostatic pressure and dam-breaking problems. To validate the suppression of the high-frequency numerical pressure oscillations, modified MPS methods with and without a removable wall are compared with published dam-breaking experiment pressure measurements.

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“…The second method solves complete Navier-Stokes equa tions using a finite difference scheme and a finite volume method with a volume of fluid (VOF) formulation for tracking the free surface [6-9J. The third approach, referred to as a meshless method and consisting of smoothed particle hydrodynamics and semi-implicit moving particles, solves the governing equations with a Lagrangian treatment [10][11][12][13]. The second method is used in the present study.…”

Section: Previous Studiesmentioning

confidence: 99%

Toward a Probabilistic Approach to Determine Nominal Values of Tank Sloshing Loads in Structural Design of Liquefied Natural Gas FPSOs

Paik

Lee

Kim

et al. 2015

Journal of Offshore Mechanics and Arctic Engineering

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The aim of this study is to develop a new probabilistic approach to determine nominal values for tank sloshing loads in structural design of LNG FPSO (liquefied natural gas, floating production, storage, and offloading units). Details of the proposed procedure are presented in a flow chart showing the key subtasks. The applicability of the method is demonstrated using an example of a hypothetical LNG FPSO operating in a natural gas site off a hypothetical oceanic region. It is noted that the proposed method is still under development for determining reliable estimates of extreme sloshing induced impact loads.It is concluded that the developed method is useful for determining the sloshing design loads in ship-shaped offshore LNG installations in combination with virtual metocean data and operational conditions.

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Numerical simulation of impact loads using a particle method

Cited by 45 publications

References 11 publications

Simulation of two‐phase flow–body interaction problems using direct forcing/fictitious domain–level set method

Simulation of two‐phase flow–body interaction problems using direct forcing/fictitious domain–level set method

On the stabilization of unphysical pressure oscillations in MPS method simulations

Toward a Probabilistic Approach to Determine Nominal Values of Tank Sloshing Loads in Structural Design of Liquefied Natural Gas FPSOs

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