New Irregular Mesh Technique Used in Three-Dimensional Simulation of Relaxation Semiconductors

The aim of this work is to simulate correctly in 3D space the phenomena that govern relaxation semiconductors. To avoid the relevant constraints of inadequate mesh a new technique for refining irregular meshing has been creating. Each length of the sample will be considered as a partial sum of a geometric series, the calculation of the argument of this series, will allow to calculate the distance between the nodes. In this paper we proposed to use an algorithm combined between Gummel and Newton Raphson algorithms to solve the partial differential equations, the linearization of transport equations is obtained by applying the finite difference method, which allowed us to calculate the relaxation time, life time and recombination rate. The results revealed appearance of a limited region called recombination front instead of charge space region, an improvement in computational time with a big precision for a 3D simulation, by letting to the user the choice of the distance to be discreet and the number of points wished without saturate the memory. This type of meshing is simple to apply and can be used to be applied as a solution to correctly simulate phenomena in structures at different areas for all the dimensions.

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Dynamic Collision Detection in Virtual Worlds Using HV Partition

ASME 1995 15th International Computers in Engineering Conference and the ASME 1995 9th Annual Engineering Database Symposium ◽

10.1115/cie1995-0818 ◽

1995 ◽

Author(s):

J. J. Fang ◽

D. E. R. Clark ◽

J. E. L. Simmons

Keyword(s):

Virtual Worlds ◽

Collision Detection ◽

Three Dimensional ◽

Convex Polyhedra ◽

Virtual Object ◽

Object Control ◽

3D Space ◽

Polyhedral Objects ◽

A New Technique ◽

Partition Method

Abstract In this paper, a simulated three-dimensional virtual world is created with a virtual 3D space ball for virtual object control. We propose a new technique called HV Partition to detect accurate collision on the assembly of two polyhedral solids in virtual simulation. This is a solid-based detection methodology achieved by automatically partitioning the object into smaller solid boxes. Mechanical components, represented by non-convex polyhedra, traversing any degree of freedom, are applied in tins environment. Using this HV Partition method, the accurate interference between two polyhedral objects can be found. The HV Partition methodology is applied following initial approximate collision detection using traditional bounding box and bounding sphere methods. The smaller the number of smaller boxes, the quicker is the performance of the collision algorithm. An automatic partition method is also given to reduce the number of smaller boxes in an object.

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Effective Particle Size Representation for Erosion Wear in Centrifugal Pump Casings

Volume 1C, Symposia: Gas-Liquid Two-Phase Flows; Gas and Liquid-Solid Two-Phase Flows; Numerical Methods for Multiphase Flow; Turbulent Flows: Issues and Perspectives; Flow Applications in Aerospace; Fluid Power; Bio-Inspired Fluid Mechanics; Flow Manipulation and Active Control; Fundamental Issues and Perspectives in Fluid Mechanics; Transport Phenomena in Energy Conversion From Clean and Sustainable Resources; Transport Phenomena in Materials Processing and Manufacturing Processes ◽

10.1115/fedsm2017-69240 ◽

2017 ◽

Cited By ~ 2

Author(s):

Krishnan V. Pagalthivarthi ◽

John M. Furlan ◽

Robert J. Visintainer

Keyword(s):

Particle Size ◽

Fluid Dynamic ◽

Three Dimensional ◽

Computation Time ◽

Particle Simulation ◽

Computational Time ◽

Two Dimensional ◽

Wide Range ◽

Dimensional Simulation ◽

Three Dimensional Simulations

For the purpose of Computational Fluid Dynamic (CFD) simulations, the broad particle size distribution (PSD) encountered in industrial slurries is classified into a discrete number of size classes. Since mono-size simulations consume much less computational time, especially in 3D simulations, it would be advantageous to determine an equivalent single particle size representation which yields the same wear distribution predictions as the multi-size simulations. This work extends the previous two-dimensional study [1], which was for a specific PSD slurry flow through three selected pumps, to determine an effective equivalent mono-size representation. The current study covers two-dimensional simulations over a wide range of pumps of varying sizes (40 pumps), 2 inlet concentrations and 4 different particle size distributions. Comparison is made between the multi-size wear prediction and different possible representative mono-size particle wear predictions. In addition, a comparison of multi-size and different mono-size results using three dimensional simulations is also shown for a typical slurry pump as a sample case to highlight that the conclusions drawn for two dimensional simulation could hold good for three dimensional simulations as well. It is observed that by using a mono-size equivalent, the computation time is 20–25% of the computation time for multi-size (6-particle) simulation.

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