scholarly journals Parallelization of DEM simulation on distributed-memory computer via three-dimensional slice grid method

2020 ◽  
Vol 6 (0) ◽  
pp. 20-00444-20-00444
Author(s):  
Kento YOKOO ◽  
Masahiro KISHIDA ◽  
Tsuyoshi YAMAMOTO
Keyword(s):  
Distributed Memory ◽  
Three Dimensional ◽  
Grid Method ◽  
Dem Simulation

Prediction of Slamming Loads on Catamaran Wetdeck Using CFD

2015 ◽  
Author(s):  
Ahmed Swidan ◽  
Giles Thomas ◽  
Dev Ranmuthugala ◽  
Irene Penesis ◽  
Walid Amin ◽  
...  
Keyword(s):  
Model Simulation ◽  
Three Dimensional ◽  
Grid Method ◽  
Computationally Efficient ◽  
Overset Grid ◽  
Force Magnitude ◽  
Overset Grid Method ◽  
Drop Tests ◽  
Transient Velocity ◽  
Transient Velocity Profile

Wetdeck slamming is one of the principal hydrodynamic loads acting on catamarans. CFD techniques are shown to successfully characterise wetdeck slamming loads, as validated through a series of controlled-speed drop tests on a three-dimensional catamaran hullform model. Simulation of water entry at constant speed by applying a fixed grid method was found to be more computationally efficient than applying an overset grid. However, the overset grid method for implementing the exact transient velocity profile resulted in better prediction of slam force magnitude. In addition the splitting force concurrent with wetdeck slam event was quantified to be 21% of the vertical slamming force.

The Vehicle Dynamical Analysis of a High-Speed Train Passing through a Tunnel

2010 ◽  
Vol 29-32 ◽  
pp. 835-840 ◽  
Author(s):  
Zhi Peng Feng ◽  
Ji Ye Zhang ◽  
Wei Hua Zhang
Keyword(s):  
High Speed ◽  
Stokes Equations ◽  
Geometric Model ◽  
Three Dimensional ◽  
Grid Method ◽  
Dynamical Analysis ◽  
High Speed Train ◽  
Flow Induced Vibration ◽  
Running Safety ◽  
Dynamics Calculation

As the speed of train increases, flow-induced vibration of trains passing through tunnels has become a subject of discussion, to investigate this phenomenon, a simplified geometric model and a vehicle dynamics model of a high-speed train traveling through a tunnel were built. To analyze the unsteady three-dimensional flow around the train, the 3-D, transient, viscous, compressible Reynolds-averaged Navier-Stokes equations combined with the k- two-equation turbulence model were solved with the finite volume method. The motion of the train was carried out using the technique of sliding grid method. The dynamics response of the train was obtained by means of the computational multi-body dynamics calculation. Meanwhile the running safety and riding comfort of the train were analyzed. With the numerical simulation, the variation of aerodynamic forces was obtained. The research founds that, vibration of the train increases drastically during it passing through a tunnel. The running safety and riding quality of the train are reduced greatly but they are in the safe range.

scholarly journals ABOUT WAVELET-BASED MULTIGRID NUMERICAL METHOD OF STRUCTURAL ANALYSIS WITH THE USE OF DISCRETE HAAR BASIS

2018 ◽  
Vol 14 (3) ◽  
pp. 83-102
Author(s):  
Marina L. Mozgaleva ◽  
Pavel A. Akimov ◽  
Taymuraz B. Kaytukov
Keyword(s):  
Structural Analysis ◽  
Three Dimensional ◽  
Grid Method ◽  
Discrete Analogue ◽  
Algebraic Equations ◽  
Initial State ◽  
Haar Basis ◽  
Linear Algebraic Equations ◽  
Gauss Method ◽  
Original Grid

he distinctive paper is devoted to so-called multigrid (particularly two-grid) method of structural analysis based on discrete Haar basis (one-dimensional, two-dimensional and three-dimensional problems are under consideration). Approximations of the mesh functions in discrete Haar bases of zero and first levels are described (the mesh function is represented as the sum in which one term is its approximation of the first level, and the second term is so-called complement (up to the initial state) on the grid of the first level). Special projectors are constructed for the spaces of vector functions of the original grid to the space of their approximation on the first-level grid and its complement (the refinement component) to the initial state. Basic scheme of the two-grid method is presented. This method allows solution of boundary problems of structural mechanics with the use of matrix operators of significantly smaller dimension. It should be noted that discrete analogue of the initial operator equation is a system of linear algebraic equations which is constructed with the use of finite element method or finite difference method. Block Gauss method can be used for direct solution.

scholarly journals Three-Dimensional Overset Adaptive-Grid Method for Compressible Flows.

1997 ◽  
Vol 63 (609) ◽  
pp. 1597-1603 ◽  
Author(s):  
Masashi YAMAKAWA ◽  
Kenichi MATSUNO ◽  
Nobuyuki SATOFUKA
Keyword(s):  
Compressible Flows ◽  
Three Dimensional ◽  
Grid Method ◽  
Adaptive Grid

scholarly journals Flow Visualization of a Three-Dimensional Wall Jet using the Tuft-Grid Method

2007 ◽  
Vol 27 (Supplement2) ◽  
pp. 51-52
Author(s):  
Haruhisa YANO ◽  
Kai OU ◽  
Yoshihiro INOUE ◽  
Shintaro YAMASHITA
Keyword(s):  
Flow Visualization ◽  
Three Dimensional ◽  
Grid Method ◽  
Wall Jet

Path planning for intelligent robot based on switching local evolutionary PSO algorithm

2016 ◽  
Vol 36 (2) ◽  
pp. 120-126 ◽  
Author(s):  
Nianyin Zeng ◽  
Hong Zhang ◽  
Yanping Chen ◽  
Binqiang Chen ◽  
Yurong Liu
Keyword(s):  
Markov Chain ◽  
Path Planning ◽  
Three Dimensional ◽  
Grid Method ◽  
Pso Algorithm ◽  
Planning Problem ◽  
Homogeneous Markov Chain ◽  
Intelligent Robot ◽  
Environment Modeling ◽  
Content Type

Purpose This paper aims to present a novel particle swarm optimization (PSO) based on a non-homogeneous Markov chain and differential evolution (DE) for path planning of intelligent robot when having obstacles in the environment. Design/methodology/approach The three-dimensional path surface of the intelligent robot is decomposed into a two-dimensional plane and the height information in z axis. Then, the grid method is exploited for the environment modeling problem. After that, a recently proposed switching local evolutionary PSO (SLEPSO) based on non-homogeneous Markov chain and DE is analyzed for the path planning problem. The velocity updating equation of the presented SLEPSO algorithm jumps from one mode to another based on the non-homogeneous Markov chain, which can overcome the contradiction between local and global search. In addition, DE mutation and crossover operations can enhance the capability of finding a better global best particle in the PSO method. Findings Finally, the SLEPSO algorithm is successfully applied to the path planning in two different environments. Comparing with some well-known PSO algorithms, the experiment results show the feasibility and effectiveness of the presented method. Originality/value Therefore, this can provide a new method for the area of path planning of intelligent robot.

Bubble Behavior at an Uneven Wall

2016 ◽  
Author(s):  
H. Shmueli ◽  
G. Ziskind ◽  
R. Letan
Keyword(s):  
Bubble Growth ◽  
Three Dimensional ◽  
Grid Method ◽  
Numerical Code ◽  
Interface Tracking ◽  
Bubble Behavior ◽  
Three Dimensional Model ◽  
Surface Geometry ◽  
Initial State ◽  
Channel Orientation

The present study deals with single bubble growth on an uneven wall. A model problem is defined and solved using a three-dimensional numerical simulation. The wall has the shape of a triangular cavity and feature vortices. The equations solved in the present study are based on macro region modelling of the bubble alone and describe its growth from the initial state to detachment from the surface and consequent motion. The model includes a simultaneous solution of conservation equations for the liquid and gaseous phases, in conjunction with three-dimensional interface tracking. The latter is achieved using the level-set method. The numerical modeling includes the multi-grid method. The complete three-dimensional model is discretized using an original in-house numerical code realized in MATLAB. Different cases of bubble growth on the triangular cavity walls are investigated. The main conclusion from the calculations is that the bubble shape and its growth rate strongly depend on its location and on the channel orientation. New features, not possible for flat walls and special for this case, are revealed and discussed. It is demonstrated that under certain conditions, the bubble is obstructed by the surface geometry. It is also shown how a growing bubble affects the flow field inside a cavity, interacting with the vortex structure.

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