Enhancement of performance and stability of MPS mesh-free particle method for multiphase flows characterized by high density ratios

2013 ◽  
Vol 242 ◽  
pp. 211-233 ◽  
Author(s):  
Abbas Khayyer ◽  
Hitoshi Gotoh
Keyword(s):  
Multiphase Flows ◽  
Free Particle ◽  
Particle Method ◽  
High Density ◽  
Mesh Free ◽  
Density Ratios

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.

A Mesh-Free Particle Method for Transient Full-Wave Simulation

2007 ◽  
Vol 43 (4) ◽  
pp. 1333-1336 ◽  
Author(s):  
Guido Ala ◽  
Elisa Francomano ◽  
Adele Tortorici ◽  
Elena Toscano ◽  
Fabio Viola
Keyword(s):  
Free Particle ◽  
Particle Method ◽  
Wave Simulation ◽  
Full Wave ◽  
Mesh Free

Efficient GPGPU implementation of a lattice Boltzmann model for multiphase flows with high density ratios

2014 ◽  
Vol 93 ◽  
pp. 1-17 ◽  
Author(s):  
Amir Banari ◽  
Christian Janßen ◽  
Stephan T. Grilli ◽  
Manfred Krafczyk
Keyword(s):  
Lattice Boltzmann ◽  
Multiphase Flows ◽  
High Density ◽  
Lattice Boltzmann Model ◽  
Density Ratios ◽  
Boltzmann Model

scholarly journals Disease contagion models coupled to crowd motion and mesh-free simulation

2021 ◽  
pp. 1-19
Author(s):  
Parveena Shamim Abdul Salam ◽  
Wolfgang Bock ◽  
Axel Klar ◽  
Sudarshan Tiwari
Keyword(s):  
Free Particle ◽  
Numerical Test ◽  
Particle Method ◽  
Coupled System ◽  
Disease Spread ◽  
Force Model ◽  
Social Force ◽  
Pedestrian Dynamics ◽  
Mesh Free ◽  
Crowd Motion

Modeling and simulation of disease spreading in pedestrian crowds have recently become a topic of increasing relevance. In this paper, we consider the influence of the crowd motion in a complex dynamical environment on the course of infection of the pedestrians. To model the pedestrian dynamics, we consider a kinetic equation for multi-group pedestrian flow based on a social force model coupled with an Eikonal equation. This model is coupled with a non-local SEIS contagion model for disease spread, where besides the description of local contacts, the influence of contact times has also been modeled. Hydrodynamic approximations of the coupled system are derived. Finally, simulations of the hydrodynamic model are carried out using a mesh-free particle method. Different numerical test cases are investigated, including uni- and bi-directional flow in a passage with and without obstacles.

The Lattice Boltzmann Equation Method for Complex Flows

2012 ◽  
Author(s):  
Laura Schaefer ◽  
Michael Ikeda ◽  
Jie Bao
Keyword(s):  
Boltzmann Equation ◽  
Lattice Boltzmann ◽  
Thermal Effects ◽  
Multiphase Flows ◽  
Density Ratio ◽  
Kinetic Equations ◽  
High Density ◽  
Lattice Boltzmann Equation ◽  
High Density Ratio ◽  
Density Ratios

The lattice Boltzmann equation (LBE) method is a promising technique for simulating fluid flows and modeling complex physics. Because the LBE model is based on microscopic models and mesoscopic kinetic equations, it offers many advantages for the study of multi-component or multiphase flows. However, there are still challenges encountered when dealing with thermal effects and multiphase flows, particularly at small scales or in varying geometries. In this paper, we discuss some techniques to overcome these challenges. First, we present an overview of the LBE method, and show how it can be extended to model multiple phases and thermal effects. Next, we describe our multi-component and multiphase (MCMP) LBE method for high density ratios. While the original formulation of Shan and Chen’s (SC) model can incorporate some multiphase and component scenarios, the density ratio of the different components is restricted (less than approximately 2.0), which limits the applications. Hence, based on the SC model and improvements in the single-component multiphase (SCMP) flow model reported by Yuan and Schaefer, we have developed a new model that can simulate a MCMP system with a high density ratio. An example of that system is shown. Finally, we have developed a parallel computation LBE method based on the Compute Unified Device Architecture for NVIDIA GPUs. Using this method, we are able to efficiently model a number of phases and length scales, examples of which are presented.

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