scholarly journals Numerical Investigation on the Kinetic Characteristics of the Yigong Debris Flow in Tibet, China

Water ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1076
Author(s):  
Zili Dai ◽  
Kai Xu ◽  
Fawu Wang ◽  
Hufeng Yang ◽  
Shiwei Qin
Keyword(s):  
Debris Flow ◽  
Three Dimensional ◽  
Field Investigation ◽  
Kinetic Characteristics ◽  
Runout Distance ◽  
Barrier Lake ◽  
Particle Hydrodynamics ◽  
Sph Model ◽  
Simulation Results ◽  
Three Dimensional Models

To analyze the kinetic characteristics of a debris flow that occurred on 9 April 2000 in Tibet, China, a meshfree numerical method named smoothed particle hydrodynamics (SPH) is introduced, and two-dimensional and three-dimensional models are established in this work. Based on the numerical simulation, the motion process of this debris flow is reproduced, and the kinetic characteristics are analyzed combining with the field investigation data. In the kinetic analysis, the flow velocity, runout distance, deposition, and energy features are discussed. Simulation results show that the debris flow mass undergoes an acceleration stage after failure, then the kinetic energy gradually dissipates due to the friction and collision during debris flow propagation. Finally, the debris flow mass blocks the Yigong river and forms a huge dam and an extensive barrier lake. The peak velocity is calculated to be about 100 m/s, and the runout distance is approximately 8000 m. The simulation results basically match the data measured in field, thus verifying the good performance of the presented SPH model. This approach can predict hazardous areas and estimate the hazard intensity of catastrophic debris flow.

scholarly journals Numerical investigation on the kinetic characteristics of the Yigong landslide in Tibet, China

2020 ◽  
Author(s):  
Zili Dai ◽  
Fawu Wang ◽  
Hufeng Yang ◽  
Shiwei Qin
Keyword(s):  
Three Dimensional ◽  
Landslide Dam ◽  
Field Investigation ◽  
Kinetic Characteristics ◽  
Barrier Lake ◽  
Landslide Mass ◽  
Particle Hydrodynamics ◽  
Sph Model ◽  
Simulation Results ◽  
Three Dimensional Models

Abstract. To analyse the kinetic characteristics of a rapid landslide that occurred on 9 April 2000 in Tibet, China, a meshfree numerical method named Smoothed Particle Hydrodynamics (SPH) is introduced, and two-dimensional and three-dimensional models are established in this work. Based on the numerical simulation, the landslide motion process is reproduced and the kinetic characteristics are analysed combined with the field investigation data. In the kinetic analysis, the landslide velocity, run-out distance, landslide accumulation, and energy features are discussed. Simulation results show that the landslide mass undergoes an acceleration stage after failure, then the kinetic energy dissipates gradually due to the friction and collision during the landslide propagation. Finally, the landslide mass blocks the Yigong river and forms a huge landslide dam and an extensive barrier lake. The peak velocity is calculated to be about 100 m/s, and the run-out distance is approximately 8,500 m. The simulation results basically match the data measured in field, thus verifying the good performance of the presented SPH model. This approach can provide a new way to predict hazardous areas and estimate the hazard intensity of rapid landslides.

scholarly journals Viscous Elastoplastic SPH Model for Long-Distance High-Speed Landslide

2018 ◽  
Vol 16 (02) ◽  
pp. 1846011 ◽  
Author(s):  
Wentao Zhang ◽  
Chuanqi Shi ◽  
Yi An ◽  
Shihao Yang ◽  
Qingquan Liu
Keyword(s):  
Debris Flow ◽  
High Speed ◽  
Laboratory Data ◽  
Three Dimensional ◽  
Slope Instability ◽  
Flow Rule ◽  
Model Parameters ◽  
Long Distance ◽  
Particle Hydrodynamics ◽  
Sph Model

In the landslide-induced debris flow problem, the soil slope experiences three stages: slope instability, debris flow and deposition. This study develops a three-dimensional smoothed particle hydrodynamics model which adopts elastoplastic viscous constitutive relation to simulate this complex process. The Drucker–Prager model with nonassociated plastic flow rule is implemented for slope instability and deposition and constant viscosity is used for propagation stage. The model is validated with laboratory dry-granular dam-break experiments. Good agreements are found between the simulated results and the laboratory data on both the shape evolution and the velocity field. Then, we use the model to study the Yigong avalanche after detailed discussion of model parameters, the time of duration, deposited scope and estimated velocity essentially agree with site survey. Thus, the model is able to simulate instability and flow of dense granular materials at both experimental and field scale, and it could be a powerful tool for the landslide-induced debris flow study.

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.

Smoothed Particle Hydrodynamics Simulations of Whole Blood in Three-Dimensional Shear Flow

2020 ◽  
Vol 17 (10) ◽  
pp. 2050009
Author(s):  
Sisi Tan ◽  
Mingze Xu
Keyword(s):  
Shear Flow ◽  
Smoothed Particle Hydrodynamics ◽  
Whole Blood ◽  
Blood Cells ◽  
White Blood Cells ◽  
Three Dimensional ◽  
Immersed Boundary ◽  
Particle Hydrodynamics ◽  
Sph Model ◽  
Smoothed Particle

Numerical modeling of whole blood still faces great challenges although significant progress has been achieved in recent decades, because of the large differences of physical and geometric properties among blood components, including red blood cells (RBCs), platelets (PLTs) and white blood cells (WBCs). In this work, we develop a three-dimensional (3D) smoothed particle hydrodynamics (SPH) model to study the whole blood in shear flow. The immersed boundary method (IBM) is used to deal with the interaction between the fluid and cells, which provides a possibility to model the RBCs, PLTs and WBCs simultaneously. The deformation of a small capsule, comparable to a PLT in size, is first examined to show the feasibility of SPH model for the PLTs’ behaviors. The motion of a single RBC in shear flow is then studied, and three typical modes, tank-treading, swinging and tumbling motions, are reproduced, which further confirm the reliability of the SPH model. After that, a simulation of the whole blood in shear flow is carried out, in which the margination trend is observed for both PLTs and WBC. This shows the capability of SPH model with IBM for the simulation of whole blood.

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.

Simulation on Multi-Oil-Cavity and Multi-Oil-Pad Hydrostatic Bearings

2013 ◽  
Vol 274 ◽  
pp. 274-277 ◽  
Author(s):  
Xiao Qiu Xu ◽  
Jun Peng Shao ◽  
Xiao Dong Yang ◽  
Yan Qin Zhang ◽  
Xiao Dong Yu ◽  
...  
Keyword(s):  
Hydraulic System ◽  
Thrust Bearing ◽  
Three Dimensional ◽  
Structure Design ◽  
Analysis Software ◽  
Hydrostatic Bearing ◽  
Hydrostatic Bearings ◽  
Simulation Results ◽  
Three Dimensional Models ◽  
Volume Method

Taking multi-oil-cavity and multi-oil-pad hydrostatic bearings as studied projects, firstly make brief instructions for structure characteristics and working principal of hydraulic system; Then, build three-dimensional models of multi-oil-cavity and multi-oil-pad hydrostatic bearings respectively. Adopting finite volume method, oil film mesh is generated by universal finite analysis software CFD; then, carry on numerical simulations for pressure distribution and temperature distribution of the two studied hydrostatic thrust bearing under various viscosity, and make comparative analysis for difference between the two studied hydrostatic thrust bearing. Based on the analysis of numerical simulation results, the conclusions whether oil-return groove is set for hydrostatic bearing could be received. Simulation results reveal truly the influence of setting oil-return groove or not on hydrostatic thrust bearing, and improve structure design for hydrostatic thrust bearing.

Study on Precision Forging Schemes of Hypoid Driving Gear

2012 ◽  
Vol 472-475 ◽  
pp. 692-695
Author(s):  
Jian Hua Wang ◽  
Fu Xiao Chen
Keyword(s):  
Equivalent Stress ◽  
Three Dimensional ◽  
Equivalent Strain ◽  
Precision Forging ◽  
Forming Technology ◽  
Blank Shape ◽  
Simulation Results ◽  
Three Dimensional Models ◽  
3D Software ◽  
Deform 3D

By analyzing the characteristics and forming technology of hypoid driving gear, it was suitable for adopting fully enclosed die forging principle to form the gear. Based on different forging methods, three kinds of blank shape and corresponding forming schemes were designed. The three dimensional models of blank and die were created by the UG software. The three forming schemes were simulated by the Deform-3D software. The simulation results of distribution of equivalent stress, distribution of equivalent strain and load-stroke curve were comparatively analyzed. Then the most reasonable scheme was chosen. At last, the rationality of numerical simulation can be further verified by the optimized scheme was proved by experiment.

Research on Buckling Mechanism of U Type Steel Support’s Pinnas Based on ANSYS

2012 ◽  
Vol 466-467 ◽  
pp. 1271-1274
Author(s):  
Jian Zhuang Liu ◽  
Jia Li ◽  
Li Gan ◽  
Fang Fang Du
Keyword(s):  
Stress Distribution ◽  
Cross Section ◽  
Coal Mine ◽  
Optimization Design ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Type Steel ◽  
Buckling Failure ◽  
Simulation Results ◽  
Three Dimensional Models

The prevenient mechanical research on U type steel support focuses on two dimensional analysis in the installing plan. Interested in the buckling failure of U type steel support’s pinnas in one coal mine of Huainan Group, the authors build three dimensional models to stimulating 25U and 29U support. The appealing simulation results verify ANSYS’s 3-D computational capabilities about complicated section support. The main objective of their investigation has been to obtain some knowledge of the mechanism, stress distribution, and load magnitude in the support’s deforming. Further, the deviating longitudinal load play an accelerating deformation role on its distorting, which should be paied more attention to cross-section optimization, design of support parameters, and installing way of steel lacing.

A Three-dimensional SPH Simulation of Iceberg Calving generated Waves

2021 ◽  
Author(s):  
Chao Hu ◽  
Xiao-liang Wang ◽  
Qing-quan Liu
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
Particle Hydrodynamics ◽  
Flow Field Characteristics ◽  
Smoothed Particle ◽  
Iceberg Calving ◽  
Simulation Results ◽  
Sph Simulation ◽  
The Waves ◽  
Good Agreement

<p>The calving of large-scale icebergs into the sea can generate a local tsunami that may threaten coastal communities or passing ships. A three-dimensional smoothed particle hydrodynamics model of rigid-body–fluid system is established to simulate the spatial wave generated by calving iceberg. The model is tested with simulated waves induced by a cube iceberg fall into the water body. Good agreement is obtained between simulation results and experimental data. The generation and evolution processes, and the near flow-field characteristics of the waves are analyzed. The simulation results show that waves generated in iceberg calving can generate not only a huge leading wave but also notable tailing waves. The initial propagation direction of the leading wave is determined by iceberg geometry, but as the leading wave propagates away, the water level displacement gradually develops into a semicircle wavefront which is irrelevant to iceberg geometry.</p>

scholarly journals Role of baffle shape on debris flow impact in step-pools channel: an SPH study

2021 ◽  
Author(s):  
Shuai Li ◽  
Chong ◽  
Wei Wu ◽  
shun wang ◽  
Xiaoqing Chen ◽  
...  
Keyword(s):  
Debris Flow ◽  
Empirical Relation ◽  
Three Dimensional ◽  
Numerical Results ◽  
Impact Pressure ◽  
Jet Flows ◽  
Flow Density ◽  
Particle Hydrodynamics ◽  
Pool System ◽  
The Impact

Drainage channels with step-pool system are widely used to control debris flow. The blocking of debris flow often gives rise to local damage at the steps and ba?es. Hence, the estimation of impact force of debris flow is crucial for designing step-pools channel. Existing empirical models for impact pressure prediction cannot consider the influence of baffle shape. In this work, a three-dimensional smoothed particle hydrodynamics (SPH) study on the impact behaviour of debris flows in step-pool systems is presented, where debris material is modelled using the regularizedBingham model. The SPH method is first checked using the results from two laboratory tests. Then it is used to investigate the influence of bafflee shape and flow density. Numerical results show that the impact pressure at the first ba?e highly depends on the ba?e shape; however, the largest impact pressure usually occurs at subsequent baffles due to the violent impact induced by jet flows. The peak impact pressure at the first ba?e initially grows with increasing flow density; however, it starts to drop as density is beyond a threshold. Based on the numerical results, an empirical relation considering the influence of ba?e shape is proposed for better prediction of debris impact pressure.

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