Simulation of Wedge Water Entry using Smoothed Particle Hydrodynamics Method

Farsi, M.; Ghadimi, Parviz; Zamanian, Rahim; Dashtimanesh, Abbas

doi:10.14419/ijsw.v1i1.731

Cited by 3 publications

(2 citation statements)

References 22 publications

(18 reference statements)

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“…The SPH method has an inherent advantage in solving strongly nonlinear problems of the water entry of the torpedo, induced by complex free surface splashing and large deformation. Lots of work has been conducted to improve the numerical accuracy and stability of the SPH method in capturing the moving boundary, the large deformation of the fluid, and the free surface breakage in water entry processes [6][7][8][9][10][11][12][13][14][15][16][17][18][19]. However, there remain certain shortcomings in the SPH method.…”

Section: Introductionmentioning

confidence: 99%

Study on water entry of a 3D torpedo based on the improved smooth particle hydrodynamics method

Zhang,

Ding,

et al. 2023

Preprint

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The water entry of a torpedo is a complex nonlinear problem, involving transient impact, free surface deformation, droplet splashing, and fluid-solid coupling, which poses severe challenges to traditional mesh methods. The meshless smooth particle hydrodynamics (SPH) method shows unique advantages in capturing the complex features of the water entry of the torpedo. However, it still suffers from some inherent shortcomings, such as low surface discretization accuracy, poor discretization flexibility, and low calculation efficiency. In this study, an improved adaptive SPH algorithm is proposed to accurately and efficiently investigate the water entry of the torpedo. This method integrates meshless point generation and adaptive techniques simultaneously. Numerical results demonstrate that when the torpedo vertically enters the water at different velocities, the induced impact loads acting on the head of the torpedo fluctuate significantly with two peak values at the initial stage and thereafter stabilize at a later stage. The impact load acting on the torpedo, the entry depth of the torpedo, the splash height of the droplets, and the size of the cavity generated around the torpedo increase with the increment of the entry velocity. When the torpedo enters the water at different enter angles under the same initial enter velocity, both the vertical and the horizontal movements of the torpedo are observed, which results in more complex variations of parameters along the x- and y-axes. The findings and the corresponding numerical method in this study can provide a certain basis for the future designs of the entry trajectory and the structural bearing capacity of torpedoes.

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Section: Introductionmentioning

confidence: 99%

Study on water entry of a 3D torpedo based on the improved smooth particle hydrodynamics method

Zhang,

Ding,

et al. 2023

Preprint

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“…Circular cylinders have been investigated by Greenhow (1988), Zhu (2006), and Ghadimi et al (2012), while arbitrary sections have been studied by Ghadimi et al (2013Ghadimi et al ( , 2014. Meanwhile, the smoothed particle hydrodynamics method (SPH) has also been used to analyze the wedge water entry problem by Farsi and Ghadimi (2013, 2014a, and 2014b. Yamada et al (2012), Luo et al (2012), Mutsuda and Doi (2009) Khabakhpasheva and korobkin (2012), and Mo et al (2011), are among other researchers who have investigated this problem.…”

Section: Introductionmentioning

confidence: 99%

Asymmetric Water Entry of Twin Wedges with Different Deadrises, Heel Angles, and Wedge Separations using Finite Element Based Finite Volume Method and VOF

Shademani

Ghadimi

2017

JAFM

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Asymmetric water entry of twin wedges is investigated for deadrise angles of 30 and 50 degrees, and heel angles of 5, 10, 15, and 20 degrees as well as wedge separation ratios of 1 and 2. Finite Element based Finite Volume method (FEM-FVM) is used in conjunction with Volume of Fluid (VOF) scheme for the targeted analyses. Free surface evolution and impact forces versus time are determined and comparisons of the maximum force of the wedges against each other are presented for all the considered cases. It is demonstrated that the impact force on the second wedge is always greater than the first one by a minimum of 6% and maximum of 146% which is a very significant increase in the impact force and may cause high accelerations and damage to the structure. It is also observed that the mentioned effects increase with decreasing deadrise angle and increasing heel angle.

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Numerical modeling of the freefall of two-dimensional wedge bodies into water surface

Izadi

Ghadimi

Fadavi

et al. 2018

J Braz. Soc. Mech. Sci. Eng.

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In the current paper, two-dimensional freefall of wedge water entry is investigated in 1 degree of freedom. The defined problem is numerically studied using the STAR CCM? software and by adopting an overset mesh approach. Three different chine wedges of 10°, 20°, and 30°deadrise angles are modeled. Kinematics of the considered wedges, impact loads, pressure, and the free-surface elevation around the considered wedges are presented. Based on the comparison of the computed vertical acceleration of the wedge of 20°deadrise angle against experimental data, it is determined that the proposed numerical method has relatively good accuracy in predicting the wedge response. The effects of deadrise angle and drop height on the kinematics of the wedges are also explored in different numerical simulations. Larger deadrise angle is found to yield lower and more transient vertical acceleration. It is demonstrated that impact force increases with an increase in depth, but finally approaches a constant value. Time histories of the pressure at three different points, located on the wedge wall, are also computed, indicating that an increase in the height leads to larger pressure at these points. However, when the mass is increased, the difference between the peak pressures at these points is strikingly reduced. Plots of the pressure distributions are also presented, which suggest that, as the submergence of the wedge increases, the pressure coefficient decreases. Furthermore, the pressure distributions indicate that, for the lighter wedge, the reduction in pressure coefficient is larger. Ultimately, the free surface elevation around a wedge during the freefall is presented. An increase in the pileup is observed when the submergence height is increased, but for the wedge of 30°deadrise angle, the difference between free-surface profiles at specific times is far less than that of wedges of 10°and 20°deadrise angles.

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Simulation of Wedge Water Entry using Smoothed Particle Hydrodynamics Method

Cited by 3 publications

References 22 publications

Study on water entry of a 3D torpedo based on the improved smooth particle hydrodynamics method

Study on water entry of a 3D torpedo based on the improved smooth particle hydrodynamics method

Asymmetric Water Entry of Twin Wedges with Different Deadrises, Heel Angles, and Wedge Separations using Finite Element Based Finite Volume Method and VOF

Numerical modeling of the freefall of two-dimensional wedge bodies into water surface

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