Updated Lagrangian particle hydrodynamics (ULPH) modeling of solid object water entry problems

2021 ◽  
Author(s):  
Jiale Yan ◽  
Shaofan Li ◽  
Xingyu Kan ◽  
A-Man Zhang ◽  
Lisheng Liu
Keyword(s):  
Water Entry ◽  
Solid Object ◽  
Lagrangian Particle ◽  
Particle Hydrodynamics ◽  
Updated Lagrangian

Updated Lagrangian Particle Hydrodynamics (ULPH) modeling and simulation of multiphase flows

2019 ◽  
Vol 393 ◽  
pp. 406-437 ◽  
Author(s):  
Jiale Yan ◽  
Shaofan Li ◽  
A-Man Zhang ◽  
Xingyu Kan ◽  
Peng-Nan Sun
Keyword(s):  
Modeling And Simulation ◽  
Multiphase Flows ◽  
Lagrangian Particle ◽  
Particle Hydrodynamics ◽  
Updated Lagrangian

scholarly journals Ricochet Characteristics of AUVs during Small-Angle Water Entry Process

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Guo-Xin Yan ◽  
Guang Pan ◽  
Yao Shi
Keyword(s):  
Finite Elements ◽  
Small Angle ◽  
High Efficiency ◽  
Autonomous Underwater Vehicle ◽  
Initial Conditions ◽  
Water Entry ◽  
Critical Conditions ◽  
Contact Algorithm ◽  
Particle Hydrodynamics ◽  
Sph Algorithm

When the autonomous underwater vehicle (AUV) enters the water at a small angle, the head of the AUV will be subjected to a torque that causes it to rise, which may cause the AUV to ricochet. The occurrence of ricochet will have an important impact on the trajectory stability of the AUV. In this paper, the finite element method-smoothed particle hydrodynamics (FEM-SPH) coupling algorithm, which absorbs the high efficiency of FEM and the advantages of SPH in dealing with large deformation and meshes distortion, is used to study the small-angle water entry problem of the AUV numerically. In the coupled FEM-SPH algorithm, discrete particles were used to model the zone of water, while the part of the AUV was modeled with finite elements. A contact algorithm couples the finite elements and the particles. Particular attention was paid to the influence of different head hemisphere angles and different initial conditions on the ricochet trajectory of the AUV. The critical conditions and influencing factors of the AUV ricochet phenomenon were given.

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.

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.

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