Numerical Simulation of Water Entry with Improved SPH Method

2018 ◽  
Vol 16 (02) ◽  
pp. 1846004 ◽  
Author(s):  
J. R. Shao ◽  
Y. Yang ◽  
H. F. Gong ◽  
M. B. Liu
Keyword(s):  
High Speed ◽  
Moving Objects ◽  
Treatment Algorithm ◽  
Water Entry ◽  
Sph Method ◽  
Moving Interfaces ◽  
Particle Hydrodynamics ◽  
Sph Model ◽  
Smoothed Particle ◽  
Interface Treatment

Water entry problems are very common in engineering and sciences. When objects move with relatively high speed, bubble cavities will be generated, and the behavior of moving objects will also be affected conversely. In this paper, the water entry problems are studied using smoothed particle hydrodynamics (SPH) method, which has special advantages in modeling free surfaces, moving interfaces. First, an improved fluid–solid interface treatment algorithm is presented, whose effectiveness is validated by a water entry of a buoyant cylinder. Then the water entry with different velocities and directions are researched. It is found that the velocities and angles of the moving objects will affect the movement of the object greatly, and the SPH model can give optimal predication of these corresponding conditions.

scholarly journals Numerical Simulation of Non-Homogeneous Viscous Debris-Flows Based on the Smoothed Particle Hydrodynamics (SPH) Method

Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2314 ◽  
Author(s):  
Shu Wang ◽  
Anping Shu ◽  
Matteo Rubinato ◽  
Mengyao Wang ◽  
Jiping Qin
Keyword(s):  
Debris Flow ◽  
Water Content ◽  
Smoothed Particle Hydrodynamics ◽  
Debris Flows ◽  
Sph Method ◽  
Particle Hydrodynamics ◽  
Sph Model ◽  
Smoothed Particle ◽  
The Impact ◽  
Kinetic And Potential Energies

Non-homogeneous viscous debris flows are characterized by high density, impact force and destructiveness, and the complexity of the materials they are made of. This has always made these flows challenging to simulate numerically, and to reproduce experimentally debris flow processes. In this study, the formation-movement process of non-homogeneous debris flow under three different soil configurations was simulated numerically by modifying the formulation of collision, friction, and yield stresses for the existing Smoothed Particle Hydrodynamics (SPH) method. The results obtained by applying this modification to the SPH model clearly demonstrated that the configuration where fine and coarse particles are fully mixed, with no specific layering, produces more fluctuations and instability of the debris flow. The kinetic and potential energies of the fluctuating particles calculated for each scenario have been shown to be affected by the water content by focusing on small local areas. Therefore, this study provides a better understanding and new insights regarding intermittent debris flows, and explains the impact of the water content on their formation and movement processes.

An Algorithm for Fluid–Solid Coupling Based on SPH Method and Its Preliminary Verification

2018 ◽  
Vol 16 (02) ◽  
pp. 1846008
Author(s):  
X. J. Ma ◽  
M. Geni ◽  
A. F. Jin
Keyword(s):  
Elastic Solid ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Sph Method ◽  
Particle Hydrodynamics ◽  
Sph Model ◽  
Smoothed Particle ◽  
Feasible Algorithm ◽  
Coupling Algorithm ◽  
Good Agreement

Based on the fundamental theory of smoothed-particle hydrodynamics (SPH), a feasible algorithm for fluid–solid coupling on interface is applied to describe the dynamic behavior of fluid and solid by utilizing continuum mechanics governing equations. Numerical simulation is conducted based on the proposed SPH model and the fluid–solid interface coupling algorithm, and good agreement is observed with the experiment results. It is shown in the results that the present SPH model is able to effectively and accurately simulate the free-surface flow of fluid, deformation of the elastic solid and the fluid–solid impacting.

scholarly journals Cylindrical Smoothed Particle Hydrodynamics Simulations of Water Entry

2019 ◽  
Vol 141 (7) ◽  
Author(s):  
Kai Gong ◽  
Songdong Shao ◽  
Hua Liu ◽  
Pengzhi Lin ◽  
Qinqin Gui
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Three Dimensional ◽  
Water Entry ◽  
Surface Velocity ◽  
Governing Equations ◽  
Pressure Fields ◽  
Particle Hydrodynamics ◽  
Sph Model ◽  
Smoothed Particle ◽  
Dam Break Flow

This paper presents a smoothed particle hydrodynamics (SPH) modeling technique based on the cylindrical coordinates for axisymmetrical hydrodynamic applications, thus to avoid a full three-dimensional (3D) numerical scheme as required in the Cartesian coordinates. In this model, the governing equations are solved in an axisymmetric form and the SPH approximations are modified into a two-dimensional cylindrical space. The proposed SPH model is first validated by a dam-break flow induced by the collapse of a cylindrical column of water with different water height to semi-base ratios. Then, the model is used to two benchmark water entry problems, i.e., cylindrical disk and circular sphere entry. In both cases, the model results are favorably compared with the experimental data. The convergence of model is demonstrated by comparing with the different particle resolutions. Besides, the accuracy and efficiency of the present cylindrical SPH are also compared with a fully 3D SPH computation. Extensive discussions are made on the water surface, velocity, and pressure fields to demonstrate the robust modeling results of the cylindrical SPH.

MODELLING URBAN COASTAL FLOODING THROUGH 2-D ARRAY OF BUILDINGS USING SMOOTHED PARTICLE HYDRODYNAMICS

2017 ◽  
pp. 37
Author(s):  
Sohaib Rashid Sulaiman Alahmed ◽  
Qingping Zou
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Complex Flow ◽  
Sph Method ◽  
Flooding Event ◽  
Particle Hydrodynamics ◽  
Flow Features ◽  
Sph Model ◽  
Smoothed Particle ◽  
Flood Characteristics ◽  
Water Elevation

A Smoothed Particle Hydrodynamics (SPH) method is used to investigate the flood characteristics occurring in an idealized city with two different building layouts: aligned layout and 22.5o skewed layout with respect to the direction of the incoming flow. The model results show that the water elevation is higher for the skewed city layout than that for the aligned city layout. The force due to the flood impact on the majority of buildings tend to be higher for the former than that for the latter. The complex flow features including a hydraulic jump during the flooding event are well captured by the SPH model.

The Prediction of High-Speed Landslide Movement and Simulation of Generated Impulsive Wave by SPH Method

2011 ◽  
Vol 378-379 ◽  
pp. 418-422
Author(s):  
Ji Lun Miao ◽  
Jing Qiu Chen ◽  
Cen Wen
Keyword(s):  
High Speed ◽  
Limit Equilibrium ◽  
Soil Mass ◽  
Equilibrium Analysis ◽  
Sph Method ◽  
Limit Equilibrium Analysis ◽  
Particle Hydrodynamics ◽  
Sample Test ◽  
Smoothed Particle ◽  
Landslide Movement

A sliding block model is developed for predicting the runout of high-speed landslides, which couple with SPH method (Smoothed Particle Hydrodynamics) to simulate impulse wave. This model adopts the limit equilibrium analysis approach to simulate the whole travel process of the soil mass from the onset of the landslide. The submarine landslide produces highly unsteady and rapidly varied flows, so it was very complicated by fixed grid numerical simulations. The SPH method is a meshfree particle-based Lagrangian method. A sample test is given which shows the impulsive waves generated by high-speed landslide can be reproduced well.

scholarly journals Modelling of tsunami wave run-up, breaking and impact on vertical wall by SPH method

2013 ◽  
Vol 1 (3) ◽  
pp. 2831-2857
Author(s):  
M. H. Dao ◽  
H. Xu ◽  
E. S. Chan ◽  
P. Tkalich
Keyword(s):  
Wave Breaking ◽  
Vertical Wall ◽  
Sph Method ◽  
Particle Hydrodynamics ◽  
Potential Applications ◽  
Sph Model ◽  
Smoothed Particle ◽  
Run Up ◽  
Steep Waves ◽  
Tunami N2

Abstract. Accurate predictions of wave run-up and run-down are important for coastal impact assessment of relatively long waves such as tsunami or storm waves. Wave run-up is, however, a complex process involving nonlinear build-up of the wave front, intensive wave breaking and strong turbulent flow, making the numerical approximation challenging. Recent advanced modeling methodologies could help to overcome these numerical challenges. For a demonstration, we study run-up of non-breaking and breaking solitary waves on vertical wall using two methods, the enhanced Smoothed Particle Hydrodynamics (SPH) method and the traditional non-breaking nonlinear model Tunami-N2. The Tunami-N2 model fails to capture the evolution of steep waves at the proximity of breaking that observed in the experiments. Whereas, the SPH method successfully simulate the wave propagation, breaking, impact on structure and the reform and breaking processes of wave run-down. The study also indicates that inadequate approximation of the wave breaking could lead to significant under-predictions of wave height and impact pressure on structures. The SPH model shows potential applications for accurate impact assessments of wave run-up onto coastal structures.

Specific features of mathematical modeling of ceramic plates destruction under the influence of high-speed impactors

2021 ◽  
Author(s):  
A.V. Petukov ◽  
K.A. Grin
Keyword(s):  
Mathematical Modeling ◽  
High Speed ◽  
Plate Thickness ◽  
Vertex Angle ◽  
Courant Number ◽  
Sph Method ◽  
Viscosity Coefficients ◽  
Computational Mesh ◽  
Particle Hydrodynamics ◽  
Smoothed Particle

The paper examines the issues of mathematical modeling of ceramic armor panels’ penetration by high-speed cylindrical impactors. By means of the LS-DYNA software package, a corresponding numerical simulation methodology was developed by combining a chosen method, adjusted computational mesh cells size, appropriate Courant number, and values of linear and quadratic pseudo-viscosity coefficients. The results compared with experimental data show that Lagrangian and Eulerian numerical methods, unlike the SPH method (Smoothed Particle Hydrodynamics), improperly reproduce the process of the shock wave disintegration into an elastic precursor and a plastic wave. In addition, the common size of conical fractions dislodging from the ceramic plates was determined and the influence of the scale effect on the ceramics damage patterns was shown: an increase in the absolute value of the plate thickness leads to the increase in the dislodging cone semi-vertex angle.

scholarly journals Dual-Support Smoothed Particle Hydrodynamics for Elastic Mechanics

2017 ◽  
Vol 14 (04) ◽  
pp. 1750039 ◽  
Author(s):  
Zili Dai ◽  
Huilong Ren ◽  
Xiaoying Zhuang ◽  
Timon Rabczuk
Keyword(s):  
Linear Transformation ◽  
Smoothed Particle Hydrodynamics ◽  
Three Dimensions ◽  
Benchmark Problems ◽  
Sph Method ◽  
Particle Hydrodynamics ◽  
Sph Model ◽  
Smoothed Particle ◽  
Support Domain ◽  
Elastic Mechanics

In the standard smoothed particle hydrodynamics (SPH) method, the interaction between two particles might be not pairwise when the support domain varies, which can result in a reduction of accuracy. To deal with this problem, a modified SPH approach is presented in this paper. First of all, a Lagrangian kernel is introduced to eliminate spurious distortions of the domain of material stability, and the gradient is corrected by a linear transformation so that linear completeness is satisfied. Then, concepts of support and dual-support are defined to deal with the unbalanced interactions between the particles with different support domains. Several benchmark problems in one, two and three dimensions are tested to verify the accuracy of the modified SPH model and highlight its advantages over the standard SPH method through comparisons.

Numerical Simulation of Water-Entry and Sedimentation of an Elliptic Cylinder Using Smoothed-Particle Hydrodynamics Method

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Roozbeh Saghatchi ◽  
Jafar Ghazanfarian ◽  
Mofid Gorji-Bandpy
Keyword(s):  
Free Surface ◽  
Smoothed Particle Hydrodynamics ◽  
Elliptic Cylinder ◽  
Water Entry ◽  
The Body ◽  
Numerical Code ◽  
Sph Method ◽  
Navier Stokes Equation ◽  
Particle Hydrodynamics ◽  
Smoothed Particle

This paper studies the two-dimensional water-entry and sedimentation of an elliptic cylinder using the subparticle scale (SPS) turbulence model of a Lagrangian particle-based smoothed-particle hydrodynamics (SPH) method. The motion of the body is driven by the hydrodynamic forces and the gravity. The present study shows the ability of the SPH method for the simulation of free-surface-involving and multiphase flow problems. The full Navier–Stokes equation, along with the continuity equation, have been solved as the governing equations of the problem. The accuracy of the numerical code is verified using the case of the water-entry and exit of a circular cylinder. The numerical simulations of the water-entry and sedimentation of the vertical and horizontal elliptic cylinder with the diameter ratio of 0.75 are performed at the Froude numbers of 0, 2, 5, and 8, and the specific gravities of 0.5, 0.75, 1, 1.5, 1.75, 2, and 2.5. The effect of the governing parameters and vortex shedding behind the elliptic cylinder on the trajectory curves, velocity components within the flow field, rotation angle, the velocity of ellipse, and the deformation of free-surface have been investigated in detail.

Numerical Simulation of the Protection System of Explosive Reaction Armor

2013 ◽  
Vol 760-762 ◽  
pp. 2188-2193
Author(s):  
Wen Hua Chu ◽  
Aman Zhang ◽  
Xiong Liang Yao
Keyword(s):  
Numerical Simulation ◽  
Smoothed Particle Hydrodynamics ◽  
Approximate Formula ◽  
Engineering Application ◽  
Extreme Conditions ◽  
Sph Method ◽  
Particle Hydrodynamics ◽  
Sph Model ◽  
Smoothed Particle ◽  
Explosive Reaction

There are some extreme conditions in the process of metallic jet penetrating the explosive reaction armor (ERA), such as high instantaneity, large deformation, et al. Based on the smoothed particle hydrodynamics (SPH) method, the generalized density approximate formula is proposed and the Held criterion is introduced. Then the numerical SPH model of metallic jet penetrating the explosive reaction armor is built to study its protection mechanics. The calculation result meets well with the theoretical value. The influences of some parameters, such as thickness of plate and attacking angle, on the protecting effect of explosive reaction armor are analyzed, aiming at providing references for the related engineering application.

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