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.

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.

Numerical Simulations of Regular Wave Impact on Horizontal Plate Based on SPH Methods

2013 ◽  
Vol 353-356 ◽  
pp. 3531-3536
Author(s):  
Kun Zheng ◽  
Zhao Chen Sun ◽  
Chang Ping Chen ◽  
Feng Zhou
Keyword(s):  
Estimation Method ◽  
Impact Pressure ◽  
Horizontal Plate ◽  
Regular Waves ◽  
Wave Impact ◽  
Numerical Wave Flume ◽  
Wave Flume ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
The Impact

The numerical wave flume was established for simulating the impact effects of regular waves on horizontal plate by adopting the method of Smoothed Particle Hydrodynamics (SPH).The impact process of regular waves on horizontal plate was analyzed, and the impact pressure-time curves were gotten using a new estimation method. The comparison of numerical results and experimental results shows that the new estimation method can predict the peak impact pressure more accurately.

Rogue Wave Impact on a Semi-Submersible Offshore Platform

2008 ◽  
Author(s):  
Murray Rudman ◽  
Paul Cleary ◽  
Justin Leontini ◽  
Matthew Sinnott ◽  
Mahesh Prakash
Keyword(s):  
Rogue Wave ◽  
Three Dimensional ◽  
Breaking Waves ◽  
Attractive Alternative ◽  
Wave Impact ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Dimensional Simulation ◽  
The Impact ◽  
Structural Motion

Full three-dimensional simulation of the impact of a rogue wave on a semi-submersible platform is undertaken using the Smoothed Particle Hydrodynamics (SPH) technique. Two different mooring configurations are considered: A Tension Leg Platform (TLP) system and a Taut Spread Mooring (TSM) system. It is seen that for a wave impact normal to the platform side, the heave and surge responses of the platform are significantly different for the two mooring systems. The TLP system undergoes large surge but comparatively smaller heave motions than the TSM system. The degree of pitch is very similar. The total tension in the mooring cables is approximately four times higher in the TSM system and exceeds the strength of the cables used in the simulation. SPH is seen to be an attractive alternative to standard methods for simulating the coupled interaction of highly non-linear breaking waves and structural motion.

Investigation of Fan Rotor Interaction With Pressure Disturbance Produced by Downstream Pylon

2013 ◽  
Author(s):  
Tomonori Enoki ◽  
Hidekazu Kodama ◽  
Shinya Kusuda
Keyword(s):  
Flow Field ◽  
Three Dimensional ◽  
Numerical Results ◽  
Rotor Blades ◽  
Flow Structures ◽  
Coupled Analysis ◽  
Unsteady Forces ◽  
Rotor Stator Interaction ◽  
The Impact ◽  
Potential Pressure

This paper presents an investigation of fan rotor interaction with potential pressure disturbances produced by a downstream pylon. Three-dimensional unsteady viscous analyses are performed for two fan rotor-stator-pylon configurations with different axial gaps between the stator and the pylon, and compared with the experimental results. To clarify the impact of the rotor-pylon interaction on the potential pressure flow field, a numerical analysis for the configuration in which a fan rotor is removed is also performed and compared with the numerical results with fan rotor. Actuator disk analyses are also performed to interpret the flow structures observed in the experiments and the numerical results. It is found that a fan rotor-stator interaction also exists in the fan flow field, and this may impact on the upstream propagating potential flow that dominates the unsteady forces acting on the rotor blades. A coupled analysis between fan rotor and stator is essential to accurately predict the unsteady blade force.

3D Dynamic Hydroelasticity Analysis of Light Weight Pyramidal Sandwich Plates with Imperfection Subjected to Water Impact

2013 ◽  
Vol 390 ◽  
pp. 266-272
Author(s):  
Hao Wang ◽  
Yuan Sheng Cheng ◽  
Jun Liu
Keyword(s):  
Numerical Results ◽  
Impact Pressure ◽  
Analytical Prediction ◽  
Light Weight ◽  
Water Impact ◽  
Estimation Model ◽  
Plate Structures ◽  
Maximum Deformation ◽  
The Impact ◽  
Fluid Solid Interaction

The aim of this work is to investigate the hydroelastic responses of rectangular, clamped light weight pyramidal sandwich plate structures with imperfection (LWPSPS-IM) subjected to water impact via analytical prediction and numerical simulation. Firstly, the characteristics of impact pressure and structure deformation are computed by using FEM program LS-DYNA based on the proposed 3D multi-physics computational model. Numerical results show that the impact pressure of total fluid-solid interaction (FSI) surface for LWPSPS-IM is lower than that of the perfect LWPSPS. In the theoretical approach, a novel analytical method is proposed to calculate the elastic constants of LWPSPS-IM. Then an engineering estimation model to predict the maximum deformation of LWPSPS-IM is developed, in which the total deformation is divided into two parts, i.e. local field deformation and global field deformation and they are both computed using analytical approach. Good agreement between the numerical results and ones obtained from the proposed analytical model is achieved.

scholarly journals Impact of Pile Punching on Adjacent Piles: Insights from a 3D Coupled SPH-FEM Analysis

2020 ◽  
Vol 1 (1) ◽  
pp. 47-58
Author(s):  
Laddu Bhagya Jayasinghe ◽  
Daniele Waldmann ◽  
Junlong Shang
Keyword(s):  
Three Dimensional ◽  
Fem Analysis ◽  
Field Measurements ◽  
Lateral Loads ◽  
Fem Model ◽  
Soft Clays ◽  
Stiff Clays ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
The Impact

Pile punching (or driving) affects the surrounding area where piles and adjacent piles can be displaced out of their original positions, due to horizontal loads, thereby leading to hazardous outcomes. This paper presents a three-dimensional (3D) coupled Smoothed Particle Hydrodynamics and Finite Element Method (SPH-FEM) model, which was established to investigate pile punching and its impact on adjacent piles subjected to lateral loads. This approach handles the large distortions by avoiding mesh tangling and remeshing, contributing greatly high computational efficiency. The SPH-FEM model was validated against field measurements. The results of this study indicated that the soil type in which piles were embedded affected the interaction between piles during the pile punching. A comprehensive parametric study was carried out to evaluate the impact of soil properties on the displacement of piles due to the punching of an adjacent pile. It was found that the interaction between piles was comparatively weak when the piles were driven in stiff clays; while the pile-soil interactions were much more significant in sandy soils and soft clays.

scholarly journals The Influence of an EPS Concrete Buffer Layer Thickness on Debris Dams Impacted by Massive Stones in the Debris Flow

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Xianbin Yu ◽  
Xiaoqing Chen ◽  
Wanyu Zhao ◽  
Jiangang Chen
Keyword(s):  
Debris Flow ◽  
Buffer Layer ◽  
Structural Design ◽  
Impact Force ◽  
Three Dimensional ◽  
Time History ◽  
Expanded Polystyrene ◽  
Debris Dams ◽  
The Impact ◽  
Debris Dam

The failure of debris dams impacted by the massive stones in a debris flow represents a difficult design problem. Reasonable materials selection and structural design can effectively improve the resistance impact performance of debris dams. Based on the cushioning properties of expanded polystyrene (EPS) concrete, EPS concrete as a buffer layer poured on the surface of a rigid debris dam was proposed. A three-dimensional numerical calculation model of an EPS concrete buffer layer/rigid debris dam was established. The single-factor theory revealed change rules for the thickness of the buffer layer concerning the maximal impact force of the rigid debris dam surface through numerical simulation. Moreover, the impact force-time/history curves under different calculation conditions for the rigid debris dam surface were compared. Simulation results showed that the EPS concrete buffer layer can not only effectively extend the impact time of massive stones affecting the debris dam but also reduce the impact force of the rigid debris dam caused by massive stones in the debris flow. The research results provide theoretical guidance for transferring the energy of the massive stone impact, creating a structural design and optimizing debris dams.

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 Three-dimensional simulations of the interaction between the nova ejecta, accretion disk, and companion star

2018 ◽  
Vol 613 ◽  
pp. A8 ◽  
Author(s):  
Joana Figueira ◽  
Jordi José ◽  
Enrique García-Berro ◽  
Simon W. Campbell ◽  
Domingo García-Senz ◽  
...  
Keyword(s):  
Accretion Disk ◽  
White Dwarf ◽  
Binary Systems ◽  
Three Dimensional ◽  
Chemical Properties ◽  
Potential Effect ◽  
Model Parameters ◽  
Chemical Contamination ◽  
Particle Hydrodynamics ◽  
The Impact

Context. Classical novae are thermonuclear explosions hosted by accreting white dwarfs in stellar binary systems. Material piles up on top of the white dwarf star under mildly degenerate conditions, driving a thermonuclear runaway. The energy released by the suite of nuclear processes operating at the envelope, mostly proton-capture reactions and β+-decays, heats the material up to peak temperatures ranging from 100 to 400 MK. In these events, about 10−3–10−7 M⊙, enriched in CNO and, sometimes, other intermediate-mass elements (e.g., Ne, Na, Mg, and Al) are ejected into the interstellar medium. Aims. To date, most of the efforts undertaken in the modeling of classical nova outbursts have focused on the early stages of the explosion and ejection, ignoring the interaction of the ejecta, first with the accretion disk orbiting the white dwarf and ultimately with the secondary star. Methods. A suite of 3D, smoothed-particle hydrodynamics (SPH) simulations of the interaction between the nova ejecta, accretion disk, and stellar companion were performed to fill this gap; these simulations were aimed at testing the influence of the model parameters—that is, the mass and velocity of the ejecta, mass and the geometry of the accretion disk—on the dynamical and chemical properties of the system. Results. We discuss the conditions that lead to the disruption of the accretion disk and to mass loss from the binary system. In addition, we discuss the likelihood of chemical contamination of the stellar secondary induced by the impact with the nova ejecta and its potential effect on the next nova cycle.

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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