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.

scholarly journals Review of smoothed particle hydrodynamics: towards converged Lagrangian flow modelling

2020 ◽  
Vol 476 (2241) ◽  
pp. 20190801
Author(s):  
Steven J. Lind ◽  
Benedict D. Rogers ◽  
Peter K. Stansby
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Graphics Processing Units ◽  
Wave Structure ◽  
Free Form ◽  
Mesh Free ◽  
Weakly Compressible ◽  
Particle Hydrodynamics ◽  
Massively Parallel Computing ◽  
Smoothed Particle ◽  
Graphics Processing

This paper presents a review of the progress of smoothed particle hydrodynamics (SPH) towards high-order converged simulations. As a mesh-free Lagrangian method suitable for complex flows with interfaces and multiple phases, SPH has developed considerably in the past decade. While original applications were in astrophysics, early engineering applications showed the versatility and robustness of the method without emphasis on accuracy and convergence. The early method was of weakly compressible form resulting in noisy pressures due to spurious pressure waves. This was effectively removed in the incompressible (divergence-free) form which followed; since then the weakly compressible form has been advanced, reducing pressure noise. Now numerical convergence studies are standard. While the method is computationally demanding on conventional processors, it is well suited to parallel processing on massively parallel computing and graphics processing units. Applications are diverse and encompass wave–structure interaction, geophysical flows due to landslides, nuclear sludge flows, welding, gearbox flows and many others. In the state of the art, convergence is typically between the first- and second-order theoretical limits. Recent advances are improving convergence to fourth order (and higher) and these will also be outlined. This can be necessary to resolve multi-scale aspects of turbulent flow.

scholarly journals Smoothed Particle Hydrodynamics Simulation of Orthogonal Cutting with Enhanced Thermal Modeling

2021 ◽  
Vol 11 (3) ◽  
pp. 1020
Author(s):  
Mohamadreza Afrasiabi ◽  
Hagen Klippel ◽  
Matthias Roethlin ◽  
Konrad Wegener
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Metal Cutting ◽  
Thermal Modeling ◽  
Orthogonal Cutting ◽  
Detection Algorithm ◽  
Mesh Free ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Boundary Treatments ◽  
Cutting Problems

Smoothed Particle Hydrodynamics (SPH) is a mesh-free numerical method that can simulate metal cutting problems efficiently. The thermal modeling of such processes with SPH, nevertheless, is not straightforward. The difficulty is rooted in the computationally demanding procedures regarding convergence properties and boundary treatments, both known as SPH Grand Challenges. This paper, therefore, intends to rectify these issues in SPH cutting models by proposing two improvements: (1) Implementing a higher-order Laplacian formulation to solve the heat equation more accurately. (2) Introducing a more realistic thermal boundary condition using a robust surface detection algorithm. We employ the proposed framework to simulate an orthogonal cutting process and validate the numerical results against the available experimental measurements.

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 Application of Smoothed Particle Hydrodynamics to Structural Cable Analysis

2020 ◽  
Vol 10 (24) ◽  
pp. 8983
Author(s):  
A. Ersin Dinçer ◽  
Abdullah Demir
Keyword(s):  
Numerical Model ◽  
Smoothed Particle Hydrodynamics ◽  
Solid Mechanics ◽  
Numerical Studies ◽  
Mesh Free ◽  
Longitudinal Stiffness ◽  
Damping Parameter ◽  
Particle Hydrodynamics ◽  
Deformable Bodies ◽  
Smoothed Particle

In this study, a numerical model is proposed for the analysis of a simply supported structural cable. Smoothed particle hydrodynamics (SPH)—a mesh-free, Lagrangian method with advantages for analysis of highly deformable bodies—is utilized to model a cable. In the proposed numerical model, it is assumed that a cable has only longitudinal stiffness in tension. Accordingly, SPH equations derived for solid mechanics are adapted for a structural cable, for the first time. Besides, a proper damping parameter is introduced to capture the behavior of the cable more realistically. In order to validate the proposed numerical model, different experimental and numerical studies available in the literature are used. In addition, novel experiments are carried out. In the experiments, different harmonic motions are applied to a uniformly loaded cable. Results show that the SPH method is an appropriate method to simulate the structural cable.

A model for the analysis of rapid landslide motion across three-dimensional terrain

2004 ◽  
Vol 41 (6) ◽  
pp. 1084-1097 ◽  
Author(s):  
Scott McDougall ◽  
Oldrich Hungr
Keyword(s):  
Debris Flows ◽  
Three Dimensional ◽  
Dynamic Modelling ◽  
Rock Avalanche ◽  
Stress Distributions ◽  
Flume Experiments ◽  
Mesh Distortion ◽  
Flow Slides ◽  
Particle Hydrodynamics ◽  
Smoothed Particle

A new numerical model for the dynamic analysis of rapid flow slides, debris flows, and avalanches has been developed. The model is an extension of an earlier algorithm and is implemented using a numerical method adapted from smoothed particle hydrodynamics. Its features include (i) the ability to simulate flow across complex three-dimensional terrain; (ii) the ability to allow nonhydrostatic and anisotropic internal stress distributions, coupled with strain changes through frictional relationships; (iii) the ability to simulate material entrainment; (iv) a choice of different rheological kernels, including frictional, plastic, viscous, Bingham, and Voellmy; (v) a meshless solution, which eliminates problems with mesh distortion during long displacements; and (vi) highly efficient and simple operation. The model has been tested by analysing a series of laboratory flume experiments with granular materials, both on straight and curved paths. The model is capable of accurately predicting the margins of various curving flows using a single set of input parameters. A preliminary analysis of a real rock avalanche case history is also included.Key words: landslides, debris flows, rock avalanches, runout analysis, dynamic modelling, numerical methods.

SPH Method for Simulation of Wind-Blown Sand Movements

2011 ◽  
Vol 462-463 ◽  
pp. 1019-1025
Author(s):  
A Fang Jin ◽  
Zhi Chun Yang ◽  
Mamtimin Gheni ◽  
Wen Tao Chen
Keyword(s):  
Mass Density ◽  
Computational Simulation ◽  
Sph Method ◽  
Two Phase ◽  
Self Organized ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Sand Movement ◽  
Observation Method ◽  
Physical Quantities

Wind-Blown sand movement is a complicated, non-linear, self-organized and two-phase flow. Conventional theory of mechanics and existing experimental observation method can’t describe that inherent mechanism exactly, and then appeared much difficulty of numerical method for computational simulation of wind-blown sand movement. In this paper, the smoothed particle hydrodynamics (SPH) method is used for simulating the wind-blown sand movement process. According to the characteristic of wind-blown sand movement the sand grains phase and the gas phase are modeled by considering the different kernel function and the particles size, mass, density, velocity and other physical quantities, which can movement along with controlling equation. Finally the numerical simulations are conducted for wind-blown sand movement and some reasonable results are obtained.

scholarly journals r.avaflow & r.randomwalk: two complementary and comprehensive open source GIS simulation tools for the propagation of rapid geophysical mass flows

2016 ◽  
Author(s):  
Martin Mergili ◽  
Matthias Benedikt ◽  
Julia Krenn ◽  
Jan-Thomas Fischer ◽  
Shiva P Pudasaini
Keyword(s):  
Open Source ◽  
Open Source Software ◽  
Flow Model ◽  
Rock Avalanche ◽  
Two Phase ◽  
Simulation Tools ◽  
Physically Based ◽  
Open Source Gis ◽  
Mass Flows ◽  
Geophysical Mass Flows

We present two GIS model applications for simulating the propagation of rapid geophysical mass flows: r.avaflow employs an advanced physically-based two phase flow model intended for in-detail case studies, r.randomwalk a conceptual model suitable for studies at various scales. Both tools are implemented in open source software environments serving for the needs of both research and practice. They offer a range of visualization, validation, parameter sensitivity analysis and parameter optimization functions. Some of the key functionalities of both tools are demonstrated for the Acheron rock avalanche in New Zealand.

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