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.

scholarly journals Numerical Modeling of Debris Flows Induced by Dam-Break Using the Smoothed Particle Hydrodynamics (SPH) Method

2020 ◽  
Vol 10 (8) ◽  
pp. 2954 ◽  
Author(s):  
Anping Shu ◽  
Shu Wang ◽  
Matteo Rubinato ◽  
Mengyao Wang ◽  
Jiping Qin ◽  
...  
Keyword(s):  
Debris Flow ◽  
Smoothed Particle Hydrodynamics ◽  
Formation Process ◽  
Debris Flows ◽  
Dam Break ◽  
Virtual Mass ◽  
Sph Method ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Number Of Particles

Dam-break flows may change into debris flows if certain conditions are satisfied, such as abundant loose material and steep slope. These debris flows are typically characterized by high density and can generate strong impact forces. Due to the complexity of the materials that they are made of, it has always been very challenging to numerically simulate these phenomena and accurately reproduce experimentally debris flows’ processes. Therefore, to fill this gap, the formation-movement processes of debris flows induced by dam-break were simulated numerically, modifying the existing smoothed particle hydrodynamics (SPH) method. By comparing the shape and the velocity of dam break debris flows under different configurations, it was found that when simulating the initiation process, the number of particles in the upstream section is overestimated while the number of particles in the downstream area is underestimated. Furthermore, the formation process of dam-break debris flow was simulated by three models which consider different combinations of the viscous force, the drag force and the virtual mass force. The method taking into account all these three kinds of interface forces produced the most accurate outcome for the numerical simulation of the formation process of dam-break debris flow. Finally, it was found that under different interface force models, the particle velocity distribution did not change significantly. However, the direction of the particle force changed, which is due to the fact that the SPH model considers generalized virtual mass forces, better replicating real case scenarios. The modalities of dam failures have significant impacts on the formation and development of debris flows. Therefore, the results of this study will help authorities to select safe sites for future rehabilitation and relocation projects and can also be used as an important basis for debris flow risk management. Future research will be necessary to understand more complex scenarios to investigate mechanisms of domino dam-failures and their effects on debris flows propagation.

Numerical study on debris flow in step-pools channel using smoothed particle hydrodynamics method

2020 ◽  
Author(s):  
Shuai Li ◽  
Xiaoqing Chen ◽  
Chong Peng ◽  
Jiangang Chen
Keyword(s):  
Debris Flow ◽  
Smoothed Particle Hydrodynamics ◽  
Debris Flows ◽  
Impact Force ◽  
Numerical Study ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Smoothed Particle Hydrodynamics Method ◽  
The Impact ◽  
Peak Impact Force

<p>Drainage channel with step-pool systems are widely used to control debris flow. However, the blocking of debris flow often gives rise to local damage at the steps and baffles. Hence, the estimation of impact force of debris flow is crucial for design step-pools channel. This paper presents a numerical study on the impact behavior of debris flows using SPH (Smoothed Particle Hydrodynamics) method. Some important parameters, such as the baffle shape (square, triangle, and trapezoid) and the densities of debris flows are considered to examine their influence on the impact force. The results show that the largest peak impact force is obtained at the second last baffle, rather than the first baffle. Moreover, the square baffle gives rise to the largest impact force whereas the triangle baffle bears the smallest one among the three baffles. Generally, the peak impact force increases with increasing the inflow density. However, a threshold density, beyond which the peak impact force will decrease, is suggested by the simulations. Based on the numerical results, an improved expression to predict the impact force considering the inclined angle of baffle is proposed.</p>

scholarly journals Application of Smoothed Particle Hydrodynamics (SPH) for the Simulation of Flow-like Landslides on 3D Terrains

2022 ◽  
Author(s):  
Binghui Cui ◽  
Liaojun Zhang
Keyword(s):  
Risk Assessment ◽  
Smoothed Particle Hydrodynamics ◽  
Disaster Mitigation ◽  
Sph Method ◽  
Landslide Event ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Simulation Results ◽  
Mitigation Design ◽  
The Impact

Abstract Flow-type landslide is one type of landslide that generally exhibits characteristics of high flow velocities, long jump distances, and poor predictability. Simulation of it facilitates propagation analysis and provides solutions for risk assessment and mitigation design. The smoothed particle hydrodynamics (SPH) method has been successfully applied to the simulation of two-dimensional (2D) and three-dimensional (3D) flow-like landslides. However, the influence of boundary resistance on the whole process of landslide failure is rarely discussed. In this study, a boundary algorithm considering the friction is proposed, and integrated into the boundary condition of the SPH method, and its accuracy is verified. Moreover, the Navier-Stokes equation combined with the non-Newtonian fluid rheology model was utilized to solve the dynamic behavior of the flow-like landslide. To verify its performance, the Shuicheng landslide event, which occurred in Guizhou, China, was taken as a case study. In the 2D simulation, a sensitivity analysis was conducted, and the results showed that the shearing strength parameters have more influence on the computation accuracy in comparison with the coefficient of viscosity. Afterwards, the dynamic characteristics of the landslide, such as the velocity and the impact area, were analyzed in the 3D simulation. The simulation results are in good agreement with the field investigations. The simulation results demonstrate that the SPH method performs well in reproducing the landslide process, and facilitates the analysis of landslide characteristics as well as the affected areas, which provides a scientific basis for conducting the risk assessment and disaster mitigation design.

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.

scholarly journals Numerical Simulation of Impact Behavior of Ceramic Coatings Using Smoothed Particle Hydrodynamics Method

2020 ◽  
pp. 1-25
Author(s):  
Jian Zhang ◽  
Zhe Lu ◽  
Sugrim Sagar ◽  
Hyunhee Choi ◽  
Heesung Park ◽  
...  
Keyword(s):  
Spherical Particle ◽  
Smoothed Particle Hydrodynamics ◽  
Coating Layer ◽  
Ceramic Coatings ◽  
Impact Angle ◽  
Impact Behavior ◽  
Sph Method ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
The Impact

Abstract In this work, the impact behavior of an alumina spherical particle on alumina coating is modeled using the smoothed particle hydrodynamics (SPH) method. The effects of impact angle (0°, 30°, and 60°) and velocity (100 m/s, 200 m/s, and 300 m/s) on the morphology changes of the impact pit and impacting particle, and their associated stress and energy are investigated. The results show that the combination of impact angle of 0° and velocity of 300 m/s produces the highest penetration depth and largest stress and deformation in the coating layer, while the combination of 100 m/s & 60° causes the minimum damage to the coating layer. This is because the penetration depth is determined by the vertical velocity component difference between the impacting particle and the coating layer, but irrelevant to the horizontal component. The total energy of the coating layer increases with the time, while the internal energy increases with the time after some peak values, which is due to energy transmission from the spherical particle to the coating layer and the stress shock waves. The energy transmission from impacting particle to coating layer increases with the increasing particle velocity, and decreases with the increasing inclined angle. The simulated impact pit morphology is qualitatively similar to the experimental observation. This work demonstrates that the SPH method is useful to analyze the impact behavior of ceramic coatings.

scholarly journals Pressure evaluation during dam break using weakly compressible SPH

2019 ◽  
Vol 213 ◽  
pp. 02030
Author(s):  
Petr Jančík ◽  
Tomáš Hyhlík
Keyword(s):  
Experimental Data ◽  
Smoothed Particle Hydrodynamics ◽  
Two Dimensions ◽  
Dam Break ◽  
Kinematics And Dynamics ◽  
Sph Method ◽  
Weakly Compressible ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
The Impact

This paper presents a solution of a dam break problem in two dimensions obtained with smoothed particle hydrodynamics (SPH) method. The main focus is on pressure evaluation during the impact on the wall. The used numerical method and the way of pressure evaluation are described in detail. The numerical results of the kinematics and dynamics of the flow are compared with experimental data from the literature. The abilities and limitations of the used methods are discussed.

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 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.

A Comparison of Smoothed Particle Hydrodynamics (SPH) and Coupled SPH-FEM Methods for Modeling Machining

2020 ◽  
Author(s):  
Nishant Ojal ◽  
Harish P. Cherukuri ◽  
Tony L. Schmitz ◽  
Adam W. Jaycox
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Solid Mechanics ◽  
Large Deformations ◽  
Computational Time ◽  
Depth Of Cut ◽  
Fe Model ◽  
Sph Method ◽  
Particle Hydrodynamics ◽  
Sph Model ◽  
Smoothed Particle

Abstract Smoothed Particle Hydrodynamics (SPH), a particle-based, meshless method originally developed for modeling astrophysical problems, is being increasingly used for modeling fluid mechanics and solid mechanics problems. Due to its advantages over grid-based methods in the handling of large deformations and crack formation, the method is increasingly being applied to model material removal processes. However, SPH method is computationally expensive. One way to reduce the computational time is to partition the domain into two parts where, the SPH method is used in one segment undergoing large deformations and material separation and in the second segment, the conventional finite element (FE) mesh is used. In this work, the accuracy of this SPH-FEM approach is investigated in the context of orthogonal cutting. The high deformation zone (where chips form and curl) is meshed with the SPH method, while the rest of the workpiece is modeled using the FE method. At the interface, SPH particles are coupled with FE mesh for smooth transfer of stress and displacement. The boundary conditions are applied to tool and FE zone of the workpiece. For comparison purposes, a fully-SPH model (workpiece fully discretized by SPH) is also developed. This is followed by a comparison of the results from the coupled SPH-FE model with the SPH model. A comparison of the chip profile, the cutting force, the von Mises stress and the damage parameter show that the coupled SPH-FE model reproduces the SPH model results accurately. However, the SPH-FE model takes almost 40% less time to run, a significant gain over the SPH model. Similar reduction in computation time is observed for in a micro-cutting application (depth of cut of 300 nm). Based on these results, it is concluded that coupling SPH with FEM in machining models decreases simulation time significantly while still producing accurate results. This observation suggests that three-dimensional machining problems can be modeled using the combined SPH-FEM approach without sacrificing accuracies.

The Theories and Application of Numerical Simulation with Smoothed Particle Hydrodynamics Method

2012 ◽  
Vol 531-532 ◽  
pp. 695-698
Author(s):  
Hui Lin Zhou ◽  
Hui Yong Yu ◽  
Ming Hua Pang
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Three Dimensional ◽  
Hypervelocity Impact ◽  
Particle Model ◽  
Sph Method ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Impact Problems ◽  
Numerical Calculation Method ◽  
The Impact

The Smoothed Particle Hydrodynamics (SPH) method is a very important method to resolve hypervelocity problems and the basic theory of SPH method is introduced here. Then the three dimensional hypervelocity impact problems are simulated by using the model of chair. The results of SPH analysis show that (SPH) method is a numerical calculation method to resolve hypervelocity problems without mesh model but the particle model must be getting to calculate and the program code is less than other method. By analysis the results of the simulation is reasonable and very similar to the test result. It can be concluded that the advantages of SPH demonstrated make it a good and an ideal method to simulate the impact problem and other problems.

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