Journal of Computational and Theoretical Transport最新文献

{"title":"Transport Features on Bidirectional Nanofluid Flow with Convective Heating and Variable Darcy Regime","authors":"Yusuf Olatunji Tijani, Mojeed Taiwo Akolade, Abdul Rahman Mohd Kasim","doi":"10.1080/23324309.2023.2257394","DOIUrl":"https://doi.org/10.1080/23324309.2023.2257394","url":null,"abstract":"AbstractThe performance of Au and TiO2 nanoparticles in Casson flow propelled by the rotational effect subject to convective heating and variable Darcy phenomenon is presented. As a means to contribute significantly to the biomedical industry for proper prediction and treatment of diseases like cancer, stenosis, et cetera, the Casson fluid model and magnetohydrodynamic effect are employed in this study to investigate the bidirectional-rotating boundary layer flow of blood since Casson rheology best describe the mammalian blood flow dynamics and that blood is electrically conducting in nature. The enormous performance of nanoparticles made them extremely useful; hence, they gained recognition over the conventional refrigerants and were widely used by scientists, modelers, and researchers for controlling and treating diseases via drug targeting (chemotherapy), etc. In the three-dimensional plane, the assumed electrically conducting fluid conveying nanoparticles is properly mixed through the Coriolis force, thus rotating with angular velocity λ across the variable porous medium. A numerical tool, Chebyshev Collocation Method (CCM) with pseudo-spectral approach, is deployed on the resulting transformed ODEs. Profile distributions of respective boundary layers to distinct responses of model parameters, including the Eckman, Darcy, and Biot numbers on Au and TiO2 nanoparticles, are analyzed and discussed. The dominance of TiO2 nanoparticles on both velocities is revealed, while Au nanoparticles demonstrated a higher thermal performance rate. A rise in the Darcy parameter has a diametrically opposed behavior on the primary and secondary velocities.Keywords: Casson fluidMHDrotationboundary layer flowconvective AcknowledgmentsThe authors would like to thank the Ministry of Higher Education for providing financial support under Fundamental research grant No. (FRGS/1/2023/STG06/UMP/02/7). Appreciation also goes to Universiti Malaysia Pahang Al-Sultan Abdullah for encouragement and support.Disclosure statementThe authors read and approved the manuscript, in addition declared no conflict of interest.","PeriodicalId":54305,"journal":{"name":"Journal of Computational and Theoretical Transport","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136308410","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}

{"title":"Development and Benchmarking of Charged Particle Propagation Methods in G4-ASPP","authors":"L. Stegeman, D. Fry, A. Bahadori","doi":"10.1080/23324309.2023.2240578","DOIUrl":"https://doi.org/10.1080/23324309.2023.2240578","url":null,"abstract":"Abstract A new transport tool that simultaneously accounts for the impacts of external electromagnetic fields and bulk shielding material on charged particle dynamics, G4-ASPP, was developed to streamline active radiation shielding assessment and design for spacecraft. Transport simulations were performed to assess the accuracy and speed of G4-ASPP particle propagation methods in electromagnetic fields against standard methods. The time-step-based Velocity-Verlet propagation method and an analogous distance-stepping method used in G4-ASPP were derived. The symplecticity and phase-space conservation properties of each method are discussed. Results suggest the implementation of a 4th-order Runge-Kutta distance-stepping method into G4-ASPP to improve trajectory accuracy without sacrificing much speed.","PeriodicalId":54305,"journal":{"name":"Journal of Computational and Theoretical Transport","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2023-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48456700","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}

{"title":"A Semi-Analytical Description of Radiation Coupled with Thermal Wave Conductive Transfer in Inhomogeneous Solid Cylinder","authors":"Guillaume Lambou Ymeli","doi":"10.1080/23324309.2023.2257670","DOIUrl":"https://doi.org/10.1080/23324309.2023.2257670","url":null,"abstract":"AbstractThis study presents the analytical layered solution for thermal radiations coupled with non-Fourier conductive heat transfer, formulated from the Cattaneo-Vernotte flux model in inhomogeneous solid cylinder. This solution is built by combining the spherical harmonics for volumetric thermal radiations with the D1Q3 scheme of lattice Boltzmann method (LBM) for hyperbolic energy equation where the gradient of static particle distribution function was discretized at implicit time. The accuracy of the proposed model for dealing with radiation/conduction problems is investigated by considering a semitransparent radiative transfer in a cylinder with temperature dependent thermal conductivity and space dependent scattering albedo. The effects of different parameters, such as scattering albedo, refractive index, thermal conductivity, emissivity, optical thickness, and the conduction-radiation parameter on both radiations and temperature distributions for steady and transient states are studied. Results of the present work are benchmarked against those available in the literature with accuracy greater than 98.9% for a large interval of parameter sets and therefore, excellent agreement has been obtained. It also establishes from this study that the proposed layered approach is an efficient and accurate method for radiative analysis in inhomogeneous media while the D1Q3 scheme is suitable to accommodate thermal wave front in non-Fourier analysis.Keywords: Non-Fourier conductionradiationspherical harmonics methodLattice Boltzmann methodsolid cylinder Disclosure statementNo potential conflict of interest was reported by the authors.","PeriodicalId":54305,"journal":{"name":"Journal of Computational and Theoretical Transport","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135493612","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}

{"title":"On Multivariate Distribution of <i>n-</i>Dimensional Brownian Diffusion Particle in the Fluid","authors":"Mohamed Abd Allah El-Hadidy, Alaa Awad Alzulaibani","doi":"10.1080/23324309.2023.2254951","DOIUrl":"https://doi.org/10.1080/23324309.2023.2254951","url":null,"abstract":"This work presents the multivariate distribution of an n-dimensional independent Brownian particle’s position at any time t in the fluid. To know the diffusion properties of particle in a fluid, we study some statistical properties of this distribution. Besides that, we study the estimated value of the diffusion coefficient to present more information about the particle’s motion in the fluid.","PeriodicalId":54305,"journal":{"name":"Journal of Computational and Theoretical Transport","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135494061","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}

{"title":"Evaluation of 1D Models for Particle Transport with Wall Migration in Ducts of Rectangular Cross Section","authors":"R. D. Garcia, M. T. Pazianotto, Felipe L. Frigi","doi":"10.1080/23324309.2023.2233233","DOIUrl":"https://doi.org/10.1080/23324309.2023.2233233","url":null,"abstract":"Abstract Approximate 1D models of particle transport in ducts that make use of an exponential displacement kernel to describe the effect of wall migration are evaluated for ducts of rectangular cross section. The studied models are based on the use of either one or two basis functions to approximate the transverse and azimuthal dependencies of the angular flux in the duct. Thermal-neutron reflection and transmission probabilities resulting from Monte Carlo simulations carried out with the MCNP and PHITS codes for iron, concrete and graphite ducts are used as reference solutions. It is concluded that the model built on two basis functions performs well (deviations typically < 10% in magnitude) for iron, the material for which absorption is most important, but less so for the scattering-dominated materials concrete and graphite. It is also concluded that changes in the energy distribution of the incident source have their strongest influence on the results for iron ducts.","PeriodicalId":54305,"journal":{"name":"Journal of Computational and Theoretical Transport","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2023-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41493001","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}

{"title":"A Monte Carlo Thermal Radiative Transfer Solver with Nonlinear Elimination","authors":"Adam Q. Lam, T. Palmer, T. Brunner, R. Vega","doi":"10.1080/23324309.2023.2223410","DOIUrl":"https://doi.org/10.1080/23324309.2023.2223410","url":null,"abstract":"Abstract In this paper, we present a new Monte Carlo method for solving the thermal radiative transfer (TRT) equations via the method of nonlinear elimination (NLEM). This method is inspired by the previous application of NLEM to thermal radiation diffusion. Our approach, called diffusion accelerated Implicit Monte Carlo (DAIMC), is a hybrid technique which combines a Monte Carlo method for solving a purely-absorbing transport equation and a diffusion solution that accounts for effective scattering, or absorption–reemission. The method aims to improve the implicitness of the traditional implicit Monte Carlo (IMC) method. We derive DAIMC generally for 3D Cartesian geometries, but in this paper, we present results and analysis in 1D slab geometry. These preliminary results indicate that DAIMC implementations may provide more accurate and robust TRT solutions than IMC in certain test problems.","PeriodicalId":54305,"journal":{"name":"Journal of Computational and Theoretical Transport","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2023-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41545167","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}

{"title":"Probability of Initiation in Neutron Transport","authors":"P. Brown","doi":"10.1080/23324309.2023.2222003","DOIUrl":"https://doi.org/10.1080/23324309.2023.2222003","url":null,"abstract":"Abstract We discuss the numerical solution of the nonlinear integro-differential equation for the probability of a divergent neutron chain in a stationary system (i.e., the probability of initiation (POI)). We follow the development described in Bell’s classic paper on the stochastic theory of neutron transport. As noted by Bell, the linearized form of this equation resembles the linear adjoint neutron transport equation. A matrix formalism for the discretized steady state (or forward) neutron equation in slab geometry is first developed, and is then used to derive the discrete adjoint equation. A main advantage of this discrete development is that the resulting discrete adjoint equation does not depend upon how the multigroup cross sections for the forward problem are obtained. That is, we derive the discrete adjoint directly from the discrete forward equations rather than discretizing directly the adjoint equation. This also guarantees that the discrete adjoint operator is consistent with the inner product used to define the adjoint operator. We discuss three approaches for the numerical solution of the POI equations, and present numerical results on several test problems. The three solution methods are a simple fixed point iteration, a second approach that is akin to a nonlinear Power iteration, and a third approach which uses a Newton-Krylov nonlinear solver. We also give sufficient conditions to guarantee the existence and uniqueness of nontrivial solutions to our discrete POI equations when the discrete system is supercritical, and that only the trivial solution exists when the discrete system is subcritical. Our approach is modeled after the analysis presented for the continuous POI equations by Mokhtar-Kharroubi and Jarmouni-Idrissi, and by Pazy and Rabinowitz.","PeriodicalId":54305,"journal":{"name":"Journal of Computational and Theoretical Transport","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2023-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42187760","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}

{"title":"Half-Space Albedo Problem for Triplet Anlı-Güngör Scattering","authors":"R. G. Türeci, D. Gülderen","doi":"10.1080/23324309.2023.2218843","DOIUrl":"https://doi.org/10.1080/23324309.2023.2218843","url":null,"abstract":"Abstract Introduction The Anlı-Güngör (AG) scattering function which is written in triplet form is applied to the half-space albedo problem. The aim of the study is to compare the results of albedo between the triplet AG scattering and quadratic AG scattering. Methods The analytical calculations are performed by HN method. Since the HN method is based on the usage of the Case eigenfunctions, they should be derived for the interested in this study. The tabulated results are calculated for varying the secondary neutron number and the scattering parameter. Albedo values for the triplet anisotropic scattering are convergent. A special code is used to get the numerical values in Mathematica with high precision This code holds all numerical values and the results of all algebraic process as a rational number. Thus, the round-off errors in machine language are minimized. A second and completely different numerical process is performed with the Polynomial Regression (PR) and the Artificial Neural Network (ANN). The application of the PR and ANN algorithms are studied with the calculated albedo results in this study. This application is only data mining without performing any analytical calculation. Discussion The expectation is to get bigger albedo values than the quadratic AG scattering. But the results are surprising that the triplet and the quadratic albedo results are close to each other. The result of ANN is more successful than PR results. Moreover, the intermediate values that are not in the data set can also be successfully calculated.","PeriodicalId":54305,"journal":{"name":"Journal of Computational and Theoretical Transport","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2023-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45524114","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}

{"title":"Study of Forward and Backward Scattering in Two-Region Milne Problem for Non-absorbing Medium Using a Synthetic Kernel","authors":"Dalia A. Garbiea, A. El-Depsy, M. M. Selim, O. A. Mohamedien","doi":"10.1080/23324309.2023.2219659","DOIUrl":"https://doi.org/10.1080/23324309.2023.2219659","url":null,"abstract":"Abstract In this work, the effect of an extremely anisotropic scattering function on the two-region Milne problem is studied. This scattering function divides the neutrons resulting from the collisions into three parts; part ( which moves backward, part (m) which moves forward, and part (n) which emerge isotropically from the collisions, where  + m + n = 1. The integral version of the transport equation is solved using trial functions based on Case’s eigenmodes and exponential integral function. Hence, the solution to the Milne problem is formulated in terms of characteristic quantities such as the extrapolation length and the fractional scalar flux discontinuity. Numerical results for the analytically evaluated quantities are presented. Some of our numerical results are compared with the available published results.","PeriodicalId":54305,"journal":{"name":"Journal of Computational and Theoretical Transport","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2023-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45139173","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}

{"title":"High-Order Mixed Finite Element Variable Eddington Factor Methods","authors":"Samuel S. Olivier, T. Haut","doi":"10.1080/23324309.2023.2200308","DOIUrl":"https://doi.org/10.1080/23324309.2023.2200308","url":null,"abstract":"Abstract We apply high-order mixed finite element discretization techniques and their associated preconditioned iterative solvers to the Variable Eddington Factor (VEF) equations in two spatial dimensions. The mixed finite element VEF discretizations are coupled to a high-order Discontinuous Galerkin (DG) discretization of the discrete ordinates transport equation to form effective linear transport algorithms that are compatible with high-order (curved) meshes. This combination of VEF and transport discretizations is motivated by the use of high-order mixed finite element methods in hydrodynamics calculations at the Lawrence Livermore National Laboratory (LLNL). Due to the mathematical structure of the VEF equations, the standard Raviart Thomas (RT) mixed finite elements cannot be used to approximate the vector variable in the VEF equations. Instead, we investigate three alternatives based on the use of continuous finite elements for each vector component, a non-conforming RT approach where DG-like techniques are used, and a hybridized RT method. We present numerical results that demonstrate high-order accuracy, compatibility with curved meshes, and robust and efficient convergence in iteratively solving the coupled transport-VEF system and in the preconditioned linear solvers used to invert the discretized VEF equations.","PeriodicalId":54305,"journal":{"name":"Journal of Computational and Theoretical Transport","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2023-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48483562","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}