Journal of Computational and Theoretical Transport最新文献_第6页

Motion of a Neutrally Buoyant Circular Particle in a Lid-Driven Square Cavity: A Numerical Study 中性浮力圆形粒子在盖驱动方形腔中的运动:数值研究

IF 0.7 4区工程技术

Journal of Computational and Theoretical Transport Pub Date : 2022-07-18 DOI: 10.1080/23324309.2022.2100424

Junjie Hu, Dongke Sun, Shaohua Mao, Hongmei Wu, Songyang Yu, Maosen Xu

{"title":"Motion of a Neutrally Buoyant Circular Particle in a Lid-Driven Square Cavity: A Numerical Study","authors":"Junjie Hu, Dongke Sun, Shaohua Mao, Hongmei Wu, Songyang Yu, Maosen Xu","doi":"10.1080/23324309.2022.2100424","DOIUrl":"https://doi.org/10.1080/23324309.2022.2100424","url":null,"abstract":"Abstract Understanding, predicting and controlling the motion of the solid particles in a confined cavity is significant. The motion of a neutrally buoyant circular particle in a lid-driven square cavity is studied with the lattice Boltzmann method, where the effects of the initial position, particle size and Reynolds number are investigated. The obvious characteristic of the motion of the circular particle is the existence of the limit cycle, which is the competitive result of the inertia, wall-repulsion force and vortex behavior. The limit cycle is insensitive to the initial position of the circular particle, namely, no matter where the circular particle is placed initially, the limit cycle is the same. With the increase of the particle size, the wall-repulsion force becomes stronger, which is dominant over the centrifugal force, and the limit cycle shrinks toward the center of the square cavity. With the increase of the Reynolds number, a new secondary vortex develops at the top left corner of the square cavity, and the limit cycle is pushed toward the bottom right corner of the square cavity.","PeriodicalId":54305,"journal":{"name":"Journal of Computational and Theoretical Transport","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2022-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44219679","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Bipolar Hydrodynamical Model for Charge Transport in Graphene Nanoribbons 石墨烯纳米带中电荷输运的双极流体动力学模型

IF 0.7 4区工程技术

Journal of Computational and Theoretical Transport Pub Date : 2022-06-20 DOI: 10.1080/23324309.2022.2086263

V. D. Camiola, G. Nastasi

引用次数: 0

NURBS Enhanced Virtual Element Methods for the Spatial Discretization of the Multigroup Neutron Diffusion Equation on Curvilinear Polygonal Meshes 曲线多边形网格上多组中子扩散方程空间离散化的NURBS增强虚拟元方法

IF 0.7 4区工程技术

Journal of Computational and Theoretical Transport Pub Date : 2022-06-07 DOI: 10.1080/23324309.2022.2103150

John Ferguson, Mathew Eaton, J. Kópházi

{"title":"NURBS Enhanced Virtual Element Methods for the Spatial Discretization of the Multigroup Neutron Diffusion Equation on Curvilinear Polygonal Meshes","authors":"John Ferguson, Mathew Eaton, J. Kópházi","doi":"10.1080/23324309.2022.2103150","DOIUrl":"https://doi.org/10.1080/23324309.2022.2103150","url":null,"abstract":"Abstract The Continuous Galerkin Virtual Element Method (CG-VEM) is a recent innovation in spatial discretization methods that can solve partial differential equations (PDEs) using polygonal (2D) and polyhedral (3D) meshes. Recently, a new formulation of CG-VEM was introduced which can construct VEM spaces on polygons with curvilinear edges. This paper presents the application of the curved VEM to the multigroup neutron diffusion equation and demonstrates its benefits over the conventional straight-sided VEM for a number of benchmark verification test cases with curvilinear domains. These domains were constructed using a topological data-structure developed as part of this paper, based on the doubly-connected edge list, with curves and surfaces both represented using non-uniform rational B-splines (NURBS). This data-structure is used both to specify the geometry of the reactor and to represent the curvilinear polygonal mesh. We also present two separate methods of performing integrations on curvilinear polygons, one for homogeneous functions and one for non-homogeneous functions.","PeriodicalId":54305,"journal":{"name":"Journal of Computational and Theoretical Transport","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2022-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49300312","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Benchmarks for Infinite Medium, Time Dependent Transport Problems with Isotropic Scattering 无限介质的基准，具有各向同性散射的时间相关输运问题

IF 0.7 4区工程技术

Journal of Computational and Theoretical Transport Pub Date : 2022-05-28 DOI: 10.1080/23324309.2022.2103151

W. Bennett, R. McClarren

{"title":"Benchmarks for Infinite Medium, Time Dependent Transport Problems with Isotropic Scattering","authors":"W. Bennett, R. McClarren","doi":"10.1080/23324309.2022.2103151","DOIUrl":"https://doi.org/10.1080/23324309.2022.2103151","url":null,"abstract":"Abstract The widely used AZURV1 transport benchmarks package provides a suite of solutions to isotropic scattering transport problems with a variety of initial conditions. Most of these solutions have an initial condition that is a Dirac delta function in space; as a result these benchmarks are challenging problems to use for verification tests in computer codes. Nevertheless, approximating a delta function in simulation often leads to low orders of convergence and the inability to test the convergence of high-order numerical methods. While there are examples in the literature of integration of these solutions as Green’s functions for the transport operator to produce results for more easily simulated sources, they are limited in scope and briefly explained. For a sampling of initial conditions and sources, we present solutions for the uncollided and collided scalar flux to facilitate accurate testing of source treatment in numerical solvers. The solution for the uncollided scalar flux is found in analytic form for some sources. Since integrating the Green’s functions is often nontrivial, discussion of integration difficulty and workarounds to find convergent integrals is included. Additionally, our uncollided solutions can be used as source terms in verification studies, in a similar way to the method of manufactured solutions.","PeriodicalId":54305,"journal":{"name":"Journal of Computational and Theoretical Transport","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2022-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48540065","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

A Transport Theory Route to the Dirac Equation 狄拉克方程的输运理论路径

IF 0.7 4区工程技术

Journal of Computational and Theoretical Transport Pub Date : 2022-04-16 DOI: 10.1080/23324309.2022.2063901

G. Coppa

引用次数: 0

Corrigendum - Density Transform Method for Particle Transport Problems in Spherical Geometry with Linearly Anisotropic Scattering 勘误。具有线性各向异性散射的球面几何粒子输运问题的密度变换方法

IF 0.7 4区工程技术

Journal of Computational and Theoretical Transport Pub Date : 2022-04-16 DOI: 10.1080/23324309.2022.2086264

D. C. Sahni

引用次数: 0

Higher Order U N Method for the Solution of the Neutron Diffusion Problem 求解中子扩散问题的高阶U - N方法

IF 0.7 4区工程技术

Journal of Computational and Theoretical Transport Pub Date : 2022-04-16 DOI: 10.1080/23324309.2022.2078369

H. Öztürk, Ahmet Tuğralı

引用次数: 0

An Improved Model for Light Transport in the Color Conversion Element of Light-Emitting Diodes 一种改进的发光二极管颜色转换元件中的光传输模型

IF 0.7 4区工程技术

Journal of Computational and Theoretical Transport Pub Date : 2022-04-16 DOI: 10.1080/23324309.2022.2086572

Chih-Yang Wu, D. Hong

{"title":"An Improved Model for Light Transport in the Color Conversion Element of Light-Emitting Diodes","authors":"Chih-Yang Wu, D. Hong","doi":"10.1080/23324309.2022.2086572","DOIUrl":"https://doi.org/10.1080/23324309.2022.2086572","url":null,"abstract":"Abstract Light transport with fluorescence in a phosphor layer based on radiative transfer theory is an efficient tool for understanding the performance of a phosphor-converted light-emitting diode. In this work, the models based on radiative transfer theory including light conversion of phosphor particles are developed for calculating the light transport in planar remote phosphor layers. The models developed include an ordinary differential approximation and an improved model based on the differential approximation and an integral formulation of the transmission light flux for a phosphor layer with Fresnel boundaries. We calculate the light extraction efficiency (LEE) of a phosphor layer as a function of various parameters, such as the thickness of the layer and the concentration of phosphor. The present models are validated by comparing the results obtained by the present methods, the double spherical harmonics method of order one and a Monte Carlo method. Comparing the results obtained by those methods, one can see that the improvement based on the differential approximation and integral formulation of transmission light flux for calculating the LEE can yield better results for optically thin cases.","PeriodicalId":54305,"journal":{"name":"Journal of Computational and Theoretical Transport","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2022-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44660403","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Numerical Analysis of the Monte-Carlo Noise for the Resolution of the Deterministic and Uncertain Linear Boltzmann Equation (Comparison of Non-Intrusive gPC and MC-gPC) 蒙特卡罗噪声对确定性与不确定性线性玻尔兹曼方程求解的数值分析(非侵入式gPC与MC-gPC的比较)

IF 0.7 4区工程技术

Journal of Computational and Theoretical Transport Pub Date : 2022-04-16 DOI: 10.1080/23324309.2022.2063900

Gaël Poëtte

{"title":"Numerical Analysis of the Monte-Carlo Noise for the Resolution of the Deterministic and Uncertain Linear Boltzmann Equation (Comparison of Non-Intrusive gPC and MC-gPC)","authors":"Gaël Poëtte","doi":"10.1080/23324309.2022.2063900","DOIUrl":"https://doi.org/10.1080/23324309.2022.2063900","url":null,"abstract":"Abstract Monte Carlo-generalized Polynomial Chaos (MC-gPC) has already been thoroughly studied in the literature. MC-gPC both builds a gPC based reduced model of a partial differential equation (PDE) of interest and solves it with an intrusive MC scheme in order to propagate uncertainties. This reduced model captures the behavior of the solution of a set of PDEs subject to some uncertain parameters modeled by random variables. MC-gPC is an intrusive method, it needs modifications of a code in order to be applied. This may be considered a drawback. But, on another hand, important computational gains obtained with MC-gPC have been observed on many applications. The MC-gPC resolution of Boltzmann equation has been investigated in many different ways: the wellposedness of the gPC based reduced model has been proved, the convergence with respect to the truncation order P has been theoretically and numerically studied and the coupling to nonlinear physics has been performed. But the study of the MC noise remains, to our knowledge, to be done. This is the purpose of this paper. We are interested in understanding what can be expected in terms of error estimations with respect to NMC , the number of MC particles. For this, we estimate the variances of non-intrusive gPC and MC-gPC, theoretically and numerically, and compare them in several configurations for several MC schemes (the semi-analog and the non-analog ones). The results show that the MC schemes of the literature used to solve MC-gPC present an excess of variance with respect to the non-intrusive strategies for comparable particle numbers NMC (even if this excess of variance remains acceptable and competitive in many situations).","PeriodicalId":54305,"journal":{"name":"Journal of Computational and Theoretical Transport","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2022-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49009556","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Analyzing of the Scattering Coefficients in the Neutron Transport Equation for Critical Systems 临界系统中子输运方程中的散射系数分析

IF 0.7 4区工程技术

Journal of Computational and Theoretical Transport Pub Date : 2022-04-16 DOI: 10.1080/23324309.2022.2091601

H. Koklu, O. Ozer

引用次数: 1