Research on the Coupled Water–Soil SPH Algorithm Improvement and Application Based on Two-phase Mixture Theory

2021 ◽  
Author(s):  
Jiahe Zhang ◽  
Jian Wang ◽  
Tian Wang
Keyword(s):  
Buoyant Density ◽  
Mixture Theory ◽  
Contact Forces ◽  
Viscous Drag ◽  
Two Phase ◽  
Contact Algorithm ◽  
Particle Hydrodynamics ◽  
Practical Engineering ◽  
Phase Mixture ◽  
Sph Algorithm

An improved water–soil coupling algorithm was proposed based on the two-phase mixture theory within the framework of smoothed particle hydrodynamics (SPH). In this algorithm, the buoyant density was considered in saturated soil and the stress of two phases was completely exfoliated with the Terzaghi’s effective stress principle. Then the interaction between water and soil was only constituted by viscous drag force. The proposed algorithm was validated by several numerical tests to effectively solve a series of numerical problems caused by the truncation of the kernel approximation on the interface between submerged soil and water, and it can also be a feasible measure to simulate underwater soil excavation problems without drainage and underwater landside problems. Meanwhile, combined with frictional sliding contact algorithm, the interaction between water/soil and structure which was considered as rigid can be effectively modeled, and the calculated contact forces acting on the structure are more accurate. Furthermore, this improved algorithm can be applied to deal with large deformation problems involving complex water–soil–structure interaction in hydraulic and geotechnical engineering such as underwater excavation, shield dig, caisson sinking and other practical engineering problems. It is also significant to engineering design and the improvement of construction level.

Smoothed Particle Hydrodynamics simulation of spudcan penetration based on two-phase mixture theory

2019 ◽  
Vol 173 ◽  
pp. 835-840
Author(s):  
Hao Wu ◽  
Chencong Liao ◽  
Jinjian Chen ◽  
Jianhua Wang ◽  
Jian Wang
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Mixture Theory ◽  
Two Phase ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Phase Mixture

A smoothed particle hydrodynamics (SPH) formulation of a two-phase mixture model and its application to turbulent sediment transport

2019 ◽  
Vol 31 (10) ◽  
pp. 103303 ◽  
Author(s):  
Erwan Bertevas ◽  
Thien Tran-Duc ◽  
Khoa Le-Cao ◽  
Boo Cheong Khoo ◽  
Nhan Phan-Thien
Keyword(s):  
Sediment Transport ◽  
Mixture Model ◽  
Smoothed Particle Hydrodynamics ◽  
Two Phase ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Phase Mixture

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 A parameter-free total Lagrangian smooth particle hydrodynamics algorithm applied to problems with free surfaces

2021 ◽  
Author(s):  
Kenny W. Q. Low ◽  
Chun Hean Lee ◽  
Antonio J. Gil ◽  
Jibran Haider ◽  
Javier Bonet
Keyword(s):  
Ad Hoc ◽  
Wide Spectrum ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Point Of View ◽  
Numerical Dissipation ◽  
Lagrangian Description ◽  
Smooth Particle Hydrodynamics ◽  
Particle Hydrodynamics ◽  
Sph Algorithm

AbstractThis paper presents a new Smooth Particle Hydrodynamics computational framework for the solution of inviscid free surface flow problems. The formulation is based on the Total Lagrangian description of a system of first-order conservation laws written in terms of the linear momentum and the Jacobian of the deformation. One of the aims of this paper is to explore the use of Total Lagrangian description in the case of large deformations but without topological changes. In this case, the evaluation of spatial integrals is carried out with respect to the initial undeformed configuration, yielding an extremely efficient formulation where the need for continuous particle neighbouring search is completely circumvented. To guarantee stability from the SPH discretisation point of view, consistently derived Riemann-based numerical dissipation is suitably introduced where global numerical entropy production is demonstrated via a novel technique in terms of the time rate of the Hamiltonian of the system. Since the kernel derivatives presented in this work are fixed in the reference configuration, the non-physical clumping mechanism is completely removed. To fulfil conservation of the global angular momentum, a posteriori (least-squares) projection procedure is introduced. Finally, a wide spectrum of dedicated prototype problems is thoroughly examined. Through these tests, the SPH methodology overcomes by construction a number of persistent numerical drawbacks (e.g. hour-glassing, pressure instability, global conservation and/or completeness issues) commonly found in SPH literature, without resorting to the use of any ad-hoc user-defined artificial stabilisation parameters. Crucially, the overall SPH algorithm yields equal second order of convergence for both velocities and pressure.

scholarly journals Depth-Integrated Two-Phase Modeling of Two Real Cases: A Comparison between r.avaflow and GeoFlow-SPH Codes

2021 ◽  
Vol 11 (12) ◽  
pp. 5751
Author(s):  
Seyed Ali Mousavi Tayebi ◽  
Saeid Moussavi Tayyebi ◽  
Manuel Pastor
Keyword(s):  
Rock Avalanche ◽  
Two Phase ◽  
Simulation Code ◽  
Simulation Tools ◽  
Mesh Free ◽  
Particle Hydrodynamics ◽  
Landslide Evolution ◽  
Smoothed Particle ◽  
Hazard And Risk ◽  
Comparison Of The Results

Due to the growing populations in areas at high risk of natural disasters, hazard and risk assessments of landslides have attracted significant attention from researchers worldwide. In order to assess potential risks and design possible countermeasures, it is necessary to have a better understanding of this phenomenon and its mechanism. As a result, the prediction of landslide evolution using continuum dynamic modeling implemented in advanced simulation tools is becoming more important. We analyzed a depth-integrated, two-phase model implemented in two different sets of code to stimulate rapid landslides, such as debris flows and rock avalanches. The first set of code, r.avaflow, represents a GIS-based computational framework and employs the NOC-TVD numerical scheme. The second set of code, GeoFlow-SPH, is based on the mesh-free numerical method of smoothed particle hydrodynamics (SPH) with the capability of describing pore pressure’s evolution along the vertical distribution of flowing mass. Two real cases of an Acheron rock avalanche and Sham Tseng San Tsuen debris flow were used with the best fit values of geotechnical parameters obtained in the prior modeling to investigate the capabilities of the sets of code. Comparison of the results evidenced that both sets of code were capable of properly reproducing the run-out distance, deposition thickness, and deposition shape in the benchmark exercises. However, the values of maximum propagation velocities and thickness were considerably different, suggesting that using more than one set of simulation code allows us to predict more accurately the possible scenarios and design more effective countermeasures.

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