Stable time step estimates for mesh-free particle methods

2012 ◽  
Vol 91 (4) ◽  
pp. 450-456 ◽  
Author(s):  
Grand Roman Joldes ◽  
Adam Wittek ◽  
Karol Miller
Keyword(s):  
Free Particle ◽  
Particle Methods ◽  
Time Step ◽  
Mesh Free

scholarly journals Recent Progress on Mesh-free Particle Methods for Simulations of Multi-phase Flows: A Review

2020 ◽  
Vol 37 (0) ◽  
pp. 132-144 ◽  
Author(s):  
Mikio Sakai ◽  
Yuki Mori ◽  
Xiaosong Sun ◽  
Kazuya Takabatake
Keyword(s):  
Recent Progress ◽  
Free Particle ◽  
Particle Methods ◽  
Mesh Free ◽  
Multi Phase

Implementation of three-dimensional physical reflective boundary conditions in mesh-free particle methods for continuum fluid dynamics: Validation tests and case studies

2019 ◽  
Vol 31 (10) ◽  
pp. 103606 ◽  
Author(s):  
Carlos Alberto Dutra Fraga Filho ◽  
Chong Peng ◽  
Md Rushdie Ibne Islam ◽  
Christopher McCabe ◽  
Samiullah Baig ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Boundary Conditions ◽  
Case Studies ◽  
Free Particle ◽  
Three Dimensional ◽  
Particle Methods ◽  
Mesh Free ◽  
Validation Tests

scholarly journals Multiphase mesh-free particle modeling of local sediment scouring with μ(I) rheology

2018 ◽  
Vol 21 (2) ◽  
pp. 279-294 ◽  
Author(s):  
Ehsan Jafari Nodoushan ◽  
Ahmad Shakibaeinia
Keyword(s):  
Free Particle ◽  
Particle Methods ◽  
Viscoplastic Fluid ◽  
Particle Model ◽  
Numerical Techniques ◽  
Low Viscosity ◽  
Particle Modeling ◽  
Mesh Free ◽  
Weakly Compressible ◽  
Moving Particle

Abstract Sediment scouring is a common example of highly dynamic sediment transport. Considering its complexities, the accurate prediction of such a highly dynamic multiphase granular flow system is a challenge for the traditional numerical techniques that rely on a mesh system. The mesh-free particle methods are a newer generation of numerical techniques with an inherent ability to deal with the deformations and fragmentations of a multiphase continuum. This study aims at developing and evaluating a multiphase mesh-free particle model based on the weakly compressible moving particle semi-implicit (WC-MPS) formulation for simulation of sediment scouring. The sediment material is considered as a non-Newtonian viscoplastic fluid, whose behavior is predicted using a regularized μ(I) rheological model in combination with pressure-dependent yield criteria. The model is first validated for a benchmark problem of viscoplastic Poiseuille flow. It is then applied and evaluated for the study of two classical sediment scouring cases. The results show that the high-velocity flow currents and the circulations can create a low-viscosity region on the surface of the sediment continuum. Comparing the numerical results with the experimental measurements shows a good accuracy in prediction of the sediment profile, especially the shape and dimensions of the scour hole.

Numerical Simulation of Behavior of Sand Particles during High-Speed Penetration with Particle Method

2016 ◽  
Vol 715 ◽  
pp. 198-202
Author(s):  
Ryota Shimono ◽  
Keiko Watanabe
Keyword(s):  
Numerical Simulation ◽  
High Speed ◽  
Free Particle ◽  
Particle Method ◽  
Particle Methods ◽  
Sand Particle ◽  
Mesh Free ◽  
Research Themes ◽  
Macro Scale ◽  
Sand Particles

The phenomena that occur during high-speed penetration of a projectile into sand particles are interesting subjects in engineering. The macro-scale research themes are the behavior of the ejected sand particles and the progress of the high-speed projectile, while the micro-scale research themes are the deformation and fragmentation of a single sand particle. Studies of these unique phenomena were conducted using both experiments and numerical simulation. Although accurate simulation of the behavior of sand particles during high-speed penetration is difficult because sand particles have characteristics of both fluids and solids, the reproducibility of the actual phenomena has improved in recent years with the development of particle methods. In our research, we conducted simulations of the phenomena using Smoothed Particle Hydrodynamics (SPH), which is a mesh-free, particle-based method. The results showed the possibility of accurate reproduction during high-speed projectile penetration into sand particles at the macro-scale.

MPS–FEM PARTITIONED COUPLING APPROACH FOR FLUID–STRUCTURE INTERACTION WITH FREE SURFACE FLOW

2014 ◽  
Vol 11 (04) ◽  
pp. 1350101 ◽  
Author(s):  
N. MITSUME ◽  
S. YOSHIMURA ◽  
K. MUROTANI ◽  
T. YAMADA
Keyword(s):  
Free Surface ◽  
Free Particle ◽  
Fluid Structure Interaction ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Particle Methods ◽  
The Finite Element Method ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Mesh Free

Fluid–structure interaction analysis involving free surface flow has been investigated using mesh-based methods or mesh-free particle methods. While mesh-based methods have several problems in dealing with the fragmentation of geometry and moving interfaces and with the instability of nonlinear advective terms, mesh-free particle methods can deal with free surface and moving boundary relatively easily. In structural analyses, the finite element method, which is a mesh-based method, has been investigated extensively and can accurately deal with not only elastic problems but also plastic and fracture problems. Thus, the present study proposes a partitioned coupling strategy for fluid–structure interaction problems involving free surfaces and moving boundaries that calculates the fluid domain using the moving particle simulation method and the structure domain using the finite element method. As the first step, we apply a conventional serial staggered algorithm as a weak coupling scheme. In addition, for the verification of the proposed method, the problem of a breaking dam on an elastic wall is calculated, and the results are compared with the results obtained by other methods.

Truncation error in mesh-free particle methods

2006 ◽  
Vol 66 (13) ◽  
pp. 2064-2085 ◽  
Author(s):  
N. J. Quinlan ◽  
M. Basa ◽  
M. Lastiwka
Keyword(s):  
Truncation Error ◽  
Free Particle ◽  
Particle Methods ◽  
Mesh Free

Flow over sills by the MPS mesh-free particle method

2011 ◽  
Vol 49 (5) ◽  
pp. 649-656 ◽  
Author(s):  
Aidin Jabbari Sahebari ◽  
Yee-Chung Jin ◽  
Ahmad Shakibaeinia
Keyword(s):  
Free Particle ◽  
Particle Method ◽  
Mesh Free

Optimization of Moving Particle Semi-Implicit (MPS) Method and Studying of Flow Instability

2018 ◽  
Author(s):  
Kailun Guo ◽  
Ronghua Chen ◽  
Suizheng Qiu ◽  
Wenxi Tian ◽  
Guanghui Su ◽  
...  
Keyword(s):  
Multiphase Flows ◽  
Flow Instability ◽  
Free Particle ◽  
Particle Method ◽  
Severe Accident ◽  
Particle Methods ◽  
Two Phase ◽  
Mps Method ◽  
Viscosity Term ◽  
Moving Particle

Multiphase flow widely exists in the nature and engineering. The two-phase flow is the highlight of the studies about the flow in the vessel and steam explosion in nuclear severe accidents. The Moving Particle Semi-implicit (MPS) method is a fully-Lagrangian particle method without grid mesh which focuses on tracking the single particle and concerns with its movement. It has advantages in tracking complex multiphase flows compared with gird methods, and thus shows great potential in predicting multiphase flows. The objective of this thesis is to develop a general multiphase particle method based on the original MPS method and thus this work is of great significance for improving the numerical method for simulating the instability in reactor severe accident and two-phase flows in vessel. This research is intended to provide a study of the instability based on the MPS method. Latest achievements of mesh-free particle methods in instability are researched and a new multiphase MPS method, which is based on the original one, for simulating instability has been developed and validated. Based on referring to other researchers’ papers, the Pressure Poisson Equation (PPE), the viscosity term, the free surface particle determination part and the surface tension model are optimized or added. The numerical simulation on stratification behavior of two immiscible flows is carried out and results are analyzed after data processing. It is proved that the improved MPS method is more accurate than the original method in analysis of multiphase flows. In this paper, the main purposes are simulating and discussing Rayleigh-Taylor (R-T) instability and Kelvin-Helmholtz (K-H) instability. R-T and K-H instability play an important role in the mixing process of many layered flows. R-T instability occurs when a lower density fluid is supported by another density higher fluid or higher density fluid is accelerated by lower density fluid, and the resulting small perturbation increases and eventually forms turbulence. K-H instability is a small disturbance for two different densities, such as waves, at the interface of the two-phase fluid after giving a fixed acceleration in the fluid. Turbulence generated by R-T instability and K-H instability has an important effect in applications such as astrophysics, geophysics, and nuclear science.

scholarly journals A physically consistent particle method for incompressible fluid flow calculation

2020 ◽  
Author(s):  
Masahiro Kondo
Keyword(s):  
Mechanical Energy ◽  
Particle Method ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Particle Methods ◽  
Analytical Mechanics ◽  
Time Step ◽  
Consistent System ◽  
Energy Behavior ◽  
Dissipation Property

AbstractIn general, mechanical energy monotonically decreases in a physically consistent system, constructed with conservative force and dissipative force. This feature is important in designing a particle method, which is a discrete system approximating continuum fluid with particles. When the discretized system can be fit into a framework of analytical mechanics, it will be a physically consistent system which prevents instability like particle scattering along with unphysical mechanical energy increase. This is the case also in incompressible particle methods. However, most incompressible particle methods do not satisfy the physical consistency, and they need empirical relaxations to suppress the system instability due to the unphysical energy behavior. In this study, a new incompressible particle method with the physical consistency, moving particle full-implicit (MPFI) method, is developed, where the discretized interaction forces are related to an analytical mechanical framework for the systems with dissipation. Moreover, a new pressure evaluation technique based on the virial theorem is proposed for the system. Using the MPFI method, static pressure, droplet extension, standing wave and dam break calculations were conducted. The capability to predict pressure and motion of incompressible free surface flow was presented, and energy dissipation property depending on the particle size and time step width was studied through the calculations.

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