Search results for " Mesh"

How to apply the Kirkwood–Buff theory to individual species in salt solutions

2013

It is generally assumed that the Kirkwood–Buff (KB) theory cannot be applied to anions and cations individually in a solution, as one cannot simulate this system in an open ensemble due to the electroneutrality constraint. By applying our recently derived KB theory for closed systems, we show that one does have access to single-ion properties in Molecular Dynamics. Our findings are supported by simulations for a model of a salt solution in which particles interact with WCA potentials, as well as for the NaCl/water system using the Particle Mesh Ewald technique for electrostatics.

A more efficient method for clustering sheet metal shapes

2007

The nesting of two-dimensional irregular shapes is a common problem which is frequently encountered by a number of industries where raw material has to be, as economically as possible, cut from a given stock sheet. A frequently recurring problem as far as cutting stock is concerned, is how to obtain the best nesting of some pieces of flat patterns which occupy minimalarea convex enclosure. The area of convex enclosure is related to the convex hull of the union of patterns which can be imagined as a large rubber band surrounding the set of all polygons. Our goal is to automatically obtain the smallest area convex shape containing all the patterns. As a matter of fact, Cheng and Rao have prop…

An improved immersed boundary method for curvilinear grids

2009

Abstract In the present paper we propose an extension of the direct-forcing immersed boundary technique, recently developed and employed by Verzicco and co-authors [Fadlun EA, Verzicco R, Orlandi P, Mohd-Yusof J. Combined immersed-boundary finite-difference methods for three-dimensional complex flow simulations. J Comput Phys 2000;161:35–60; Verzicco R, Fatica M, Iaccarino G, Moin P, Khalighi B. Large eddy simulation of a road vehicle with drag-reduction devices. AIAA J 2002;40(12):2447–55; Cristallo A, Verzicco R. Combined immersed boundary/large-eddy-simulations of incompressible three-dimensional complex flows. Flow Turbul Combust 2006;77(1–4):3–26.] and successively improved by Balaras …

geomIO: An Open‐Source MATLAB Toolbox to Create the Initial Configuration of 2‐D/3‐D Thermo‐Mechanical Simulations From 2‐D Vector Drawings

2019

Creating the initial geometry and temperature configuration of 3D numerical simulations is a challenging task. Professional tools are expensive. They often have a steep learning curve and do mostly not interface with the numerical simulation software used by the geodynamics and tectonics academic community. There, we developed geomIO (geometry Input/Output), a MATLAB toolbox to create the initial configuration of geological models regarding model geometry and temperature structure. geomIO allows users to create a geo-referenced 3D volume by drawing multiple 2D cross-sections in a standard vector graphics editor. The volume is then used to assign material properties and set up initial temper…

Eulerian–Lagrangian modeling and computational fluid dynamics simulation of wire mesh demisters in MSF plants

2016

Abstract This study focuses on computational fluid dynamics model (CFD) for simulation of demisters in multistage flash desalination (MSF). The Eulerian–Lagrangian model (steady-state and two-dimensional) was developed to simulate the demister. The model was used to simulate the flow of water vapor and brine droplets in the demister. The computational domain includes the following three zones: the vapor space above the demister, the vapor space below the demister, and the demister. The demister zone was modeled as tube banks. A sensitivity analysis of the model revealed that vapor velocity is the main parameter that affects demister performance. Additionally, the analysis indicated that vap…

Denoising 3D Models with Attributes using Soft Thresholding

2004

International audience; Recent advances in scanning and acquisition technologies allow the construction of complex models from real world scenes. However, the data of those models are generally corrupted by measurement errors. This paper describes an efficient single pass algorithm for denoising irregular meshes of scanned 3D model surfaces. In this algorithm, the frequency content of the model is assessed by a multiresolution analysis that requires only 1-ring neighbourhood without any particular parameterization of the model faces. Denoising is achieved by applying the soft thresholding method to the detail coefficients given by the multiresolution analysis. Our method is suitable for irr…

Customised products for orbital wall reconstruction: a systematic review

2021

Abstract The purpose of this systematic review was to critically analyze the recent literature to present the state of the art in customized reconstruction of orbital fractures. Three electronic databases and manual search approaches were used to identify relevant articles. Only studies with a controlled clinical study design were included. Primary outcome was defined as the status of recovery (complete/partial functional and esthetic disturbances). The benefit of intra-surgical navigation should be described. Secondary outcome was defined as the time of surgery, post-surgical events and hospitalization. A total of eight studies out of 552 records identified met the inclusion criteria. Post…

Patient‐specific titanium meshes: Future trend or current technology?

2021

Weighted Extrapolation Techniques for Finite Difference Methods on Complex Domains with Cartesian Meshes

2016

The design of numerical boundary conditions in high order schemes is a challenging problem that has been tackled in different ways depending on the nature of the problem and the scheme used to solve it numerically. In this paper we propose a technique to extrapolate the information from the computational domain to ghost cells for schemes with structured Cartesian Meshes on complex domains. This technique is based on the application of Lagrange interpolation with weighted filters for the detection of discontinuities that permits a data dependent extrapolation, with high order at smooth regions and essentially non oscillatory properties near discontinuities. This paper is a sequel of Baeza et…

Frequency Assignment and Multicoloring Powers of Square and Triangular Meshes

2005

The static frequency assignment problem on cellular networks can be abstracted as a multicoloring problem on a weighted graph, where each vertex of the graph is a base station in the network, and the weight associated with each vertex represents the number of calls to be served at the vertex. The edges of the graph model interference constraints for frequencies assigned to neighboring stations. In this paper, we first propose an algorithm to multicolor any weighted planar graph with at most $\frac{11}{4}W$ colors, where W denotes the weighted clique number. Next, we present a polynomial time approximation algorithm which garantees at most 2W colors for multicoloring a power square mesh. Fur…