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Smooth-Wall Boundary Conditions for Energy-Dissipation Turbulence Models# 能量耗散湍流模型的光滑壁边界条件
arXiv: Computational Physics Pub Date : 2019-07-30 DOI: 10.35840/2631-5009/7525
D. Hunsaker, W. Phillips, R. Spall
{"title":"Smooth-Wall Boundary Conditions for Energy-Dissipation Turbulence Models#","authors":"D. Hunsaker, W. Phillips, R. Spall","doi":"10.35840/2631-5009/7525","DOIUrl":"https://doi.org/10.35840/2631-5009/7525","url":null,"abstract":"It is shown that the smooth-wall boundary conditions specified for commonly used dissipation-based turbulence models are mathematically incorrect. It is demonstrated that when these traditional wall boundary conditions are used, the resulting formulations allow either an infinite number of solutions or no solution. Furthermore, these solutions do not enforce energy conservation and they do not properly enforce the no-slip condition at a smooth surface. This is true for all dissipation-based turbulence models, including the k-{epsilon}, k-{omega}, and k-{zeta} models. Physically correct wall boundary conditions must force both k and its gradient to zero at a smooth wall. Enforcing these two boundary conditions on k is sufficient to determine a unique solution to the coupled system of differential transport equations. There is no need to impose any wall boundary condition on {epsilon}, {omega}, or {zeta} at a smooth surface and it is incorrect to do so. The behavior of {epsilon}, {omega}, or {zeta} approaching a smooth surface is that required to satisfy the differential equations and force both k and its gradient to zero at the wall.","PeriodicalId":8424,"journal":{"name":"arXiv: Computational Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91108602","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
An iterative scheme for the generalized Peierls–Nabarro model based on the inverse Hilbert transform 基于逆希尔伯特变换的广义Peierls-Nabarro模型的迭代格式
arXiv: Computational Physics Pub Date : 2019-07-02 DOI: 10.1142/S2047684119500192
A. A. Ramabathiran
{"title":"An iterative scheme for the generalized Peierls–Nabarro model based on the inverse Hilbert transform","authors":"A. A. Ramabathiran","doi":"10.1142/S2047684119500192","DOIUrl":"https://doi.org/10.1142/S2047684119500192","url":null,"abstract":"A new semi-analytical iterative scheme is proposed in this work for solving the generalized Peierls-Nabarro model. The numerical method developed here exploits certain basic properties of the Hilbert transform to achieve the desired reduction of the non-local and non-linear equations characterizing the generalized Peierls-Nabarro model to a local fixed point iteration scheme. The method is validated with simple examples involving the 1D Peierls-Nabarro model corresponding to a sinusoidal stacking fault energy, and with calculations of the core structure of both edge and screw dislocations on the close-packed ${111}$ planes in Aluminium. An approximate technique to incorporate external stresses within the framework of the proposed iterative scheme is also discussed with applications to the equilibration of a dislocation dipole. Finally, the advantages, limitations and avenues for future extension of the proposed method are discussed.","PeriodicalId":8424,"journal":{"name":"arXiv: Computational Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76874759","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Developing an improved crystal graph convolutional neural network framework for accelerated materials discovery 开发一种改进的晶体图卷积神经网络框架，用于加速材料发现
arXiv: Computational Physics Pub Date : 2019-06-12 DOI: 10.1103/PHYSREVMATERIALS.4.063801
Cheol Woo Park, C. Wolverton
{"title":"Developing an improved crystal graph convolutional neural network framework for accelerated materials discovery","authors":"Cheol Woo Park, C. Wolverton","doi":"10.1103/PHYSREVMATERIALS.4.063801","DOIUrl":"https://doi.org/10.1103/PHYSREVMATERIALS.4.063801","url":null,"abstract":"The recently proposed crystal graph convolutional neural network (CGCNN) offers a highly versatile and accurate machine learning (ML) framework by learning material properties directly from graph-like representations of crystal structures (\"crystal graphs\"). Here, we develop an improved variant of the CGCNN model (iCGCNN) that outperforms the original by incorporating information of the Voronoi tessellated crystal structure, explicit 3-body correlations of neighboring constituent atoms, and an optimized chemical representation of interatomic bonds in the crystal graphs. We demonstrate the accuracy of the improved framework in two distinct illustrations: First, when trained/validated on 180,000/20,000 density functional theory (DFT) calculated thermodynamic stability entries taken from the Open Quantum Materials Database (OQMD) and evaluated on a separate test set of 230,000 entries, iCGCNN achieves a predictive accuracy that is significantly improved, i.e., 20% higher than that of the original CGCNN. Second, when used to assist high-throughput search for materials in the ThCr2Si2 structure-type, iCGCNN exhibited a success rate of 31% which is 310 times higher than an undirected high-throughput search and 2.4 times higher than that of the original CGCNN. Using both CGCNN and iCGCNN, we screened 132,600 compounds with elemental decorations of the ThCr2Si2 prototype crystal structure and identified a total of 97 new unique stable compounds by performing 757 DFT calculations, accelerating the computational time of the high-throughput search by a factor of 130. Our results suggest that the iCGCNN can be used to accelerate high-throughput discoveries of new materials by quickly and accurately identifying crystalline compounds with properties of interest.","PeriodicalId":8424,"journal":{"name":"arXiv: Computational Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90490760","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 141
WITHDRAWN: Modeling tissue perfusion in terms of 1d-3d embedded mixed-dimension coupled problems with distributed sources 撤回:用分布源的1d-3d嵌入式混合维耦合问题建模组织灌注
arXiv: Computational Physics Pub Date : 2019-05-02 DOI: 10.1016/j.jcpx.2020.100050
T. Koch, M. Schneider, R. Helmig, P. Jenny
{"title":"WITHDRAWN: Modeling tissue perfusion in terms of 1d-3d embedded mixed-dimension coupled problems with distributed sources","authors":"T. Koch, M. Schneider, R. Helmig, P. Jenny","doi":"10.1016/j.jcpx.2020.100050","DOIUrl":"https://doi.org/10.1016/j.jcpx.2020.100050","url":null,"abstract":"","PeriodicalId":8424,"journal":{"name":"arXiv: Computational Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80821393","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 6
Atomic-orbital-free intrinsic ferromagnetism in electrenes 电子中无原子轨道的本征铁磁性
arXiv: Computational Physics Pub Date : 2019-04-10 DOI: 10.1103/PHYSREVB.102.180407
Jun Zhou, Y. Feng, Lei Shen
{"title":"Atomic-orbital-free intrinsic ferromagnetism in electrenes","authors":"Jun Zhou, Y. Feng, Lei Shen","doi":"10.1103/PHYSREVB.102.180407","DOIUrl":"https://doi.org/10.1103/PHYSREVB.102.180407","url":null,"abstract":"We report intrinsic ferromagnetism in monolayer electrides or electrenes, in which excess electrons act as anions. Our first-principles calculations demonstrate that magnetism in such electron-rich two-dimensional (2D) materials originates from the anionic electrons rather than partially filled d orbitals, which is fundamentally different from ferromagnetism found in other 2D intrinsic magnetic materials. Taking the honeycomb LaBr$_2$ (La$^{3+}$Br$^{-}_{2}cdot e^{-}$) as an example, our calculations reveal that the excess electron is localized at the center of the hexagon, which leads to strong Stoner-instability of the associated states at the Fermi energy, resulting in spontaneous magnetization and formation of a local moment. The overlap of extended tails of the wave functions of these electrons mediates a long-range ferromagnetic interaction, contributing to a Curie temperature ($T_textrm{c}$) of 235 K and a coercive field ($H_textrm{c}$) of 0.53 T, which can be further enhanced by hole doping. The dual nature, localization and extension, of the electronic states suggests a unique mechanism in such magnetic-element-free electrenes as intrinsic 2D ferromagnets.","PeriodicalId":8424,"journal":{"name":"arXiv: Computational Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82903669","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 10
Verification of Two-Dimensional Monte Carlo Ray-Trace Methodology in Radiation Heat Transfer Analysis 二维蒙特卡罗射线追踪方法在辐射传热分析中的验证
arXiv: Computational Physics Pub Date : 2018-10-11 DOI: 10.13140/RG.2.2.12632.14089
M. Yarahmadi, J. Mahan
{"title":"Verification of Two-Dimensional Monte Carlo Ray-Trace Methodology in Radiation Heat Transfer Analysis","authors":"M. Yarahmadi, J. Mahan","doi":"10.13140/RG.2.2.12632.14089","DOIUrl":"https://doi.org/10.13140/RG.2.2.12632.14089","url":null,"abstract":"Despite the frequent appearance in the radiation heat transfer literature of articles describing Monte Carlo ray-trace (MCRT) applications to two-dimensional enclosures, no formal verification may be found of the method commonly used to determine the directional distribution of diffuse emission and reflection when estimating two-dimensional radiation distribution factors. Considered are two methods for determining the direction cosines in this situation. The results are shown to be in agreement with those obtained in the limiting case of a three-dimensional enclosure as one of its dimensions is increased.","PeriodicalId":8424,"journal":{"name":"arXiv: Computational Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76825648","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 2
HEP Software Foundation Community White Paper Working Group - Data and Software Preservation to Enable Reuse HEP软件基金会社区白皮书工作组-数据和软件保存以实现重用
arXiv: Computational Physics Pub Date : 2018-10-02 DOI: 10.2172/1488605
M. Hildreth, A. Boehnlein, K. Cranmer, S. Dallmeier, R. Gardner, T. Hacker, L. Heinrich, I. Jimenez, M. Kane, D. Katz, T. Malik, C. Maltzahn, M. Neubauer, S. Neubert, J. Pivarski, E. Sexton, J. Shiers, T. Simko, S. Smith, D. South, A. Verbytskyi, G. Watts, J. Woźniak
{"title":"HEP Software Foundation Community White Paper Working Group - Data and Software Preservation to Enable Reuse","authors":"M. Hildreth, A. Boehnlein, K. Cranmer, S. Dallmeier, R. Gardner, T. Hacker, L. Heinrich, I. Jimenez, M. Kane, D. Katz, T. Malik, C. Maltzahn, M. Neubauer, S. Neubert, J. Pivarski, E. Sexton, J. Shiers, T. Simko, S. Smith, D. South, A. Verbytskyi, G. Watts, J. Woźniak","doi":"10.2172/1488605","DOIUrl":"https://doi.org/10.2172/1488605","url":null,"abstract":"In this chapter of the High Energy Physics Software Foundation Community Whitepaper, we discuss the current state of infrastructure, best practices, and ongoing developments in the area of data and software preservation in high energy physics. A re-framing of the motivation for preservation to enable re-use is presented. A series of research and development goals in software and other cyberinfrastructure that will aid in the enabling of reuse of particle physics analyses and production software are presented and discussed.","PeriodicalId":8424,"journal":{"name":"arXiv: Computational Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84450376","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 1
Comparison of Numerical Approaches to the Time-Dependent Schr"odinger Solutions in One Dimension. 一维时变Schr odinger解的数值方法比较。
arXiv: Computational Physics Pub Date : 2018-09-24 DOI: 10.1002/HTTPS://DOI.ORG/10.1016/J.CPC.2019.05.019
H. Gharibnejad, B. Schneider, M. Leadingham, H. J. Schmale
{"title":"Comparison of Numerical Approaches to the Time-Dependent Schr\"odinger Solutions in One Dimension.","authors":"H. Gharibnejad, B. Schneider, M. Leadingham, H. J. Schmale","doi":"10.1002/HTTPS://DOI.ORG/10.1016/J.CPC.2019.05.019","DOIUrl":"https://doi.org/10.1002/HTTPS://DOI.ORG/10.1016/J.CPC.2019.05.019","url":null,"abstract":"We examine the performance of various time propagation schemes using a one-dimensional model of the hydrogen atom. In this model the exact Coulomb potential is replaced by a soft-core interaction. The model has been shown to be a reasonable representation of what occurs in the fully three-dimensional hydrogen atom. Our results show that while many numerically simple (low order) propagation schemes work, they often require quite small time-steps. Comparing them against more accurate methods, which may require more work per time-step but allow much larger time-steps, can be illuminating. We show that at least in this problem, the compute time for a number of the more accurate methods is actually less than lower order schemes. Finally, we make some remarks on what to expect in generalizing our findings to more than one dimension.","PeriodicalId":8424,"journal":{"name":"arXiv: Computational Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86991528","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Thermal Convection in the van der Waals Fluid 范德华流体中的热对流
arXiv: Computational Physics Pub Date : 2018-09-04 DOI: 10.1007/978-3-319-96469-0_9
Ju Liu
{"title":"Thermal Convection in the van der Waals Fluid","authors":"Ju Liu","doi":"10.1007/978-3-319-96469-0_9","DOIUrl":"https://doi.org/10.1007/978-3-319-96469-0_9","url":null,"abstract":"","PeriodicalId":8424,"journal":{"name":"arXiv: Computational Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73026877","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 3
Bi-fidelity approximation for uncertainty quantification and sensitivity analysis of irradiated particle-laden turbulence. 辐照粒子负载湍流不确定度量化及灵敏度分析的双保真近似。
arXiv: Computational Physics Pub Date : 2018-08-01 DOI: 10.2172/1463950
Hillary R. Fairbanks, L. Jofre, G. Geraci, G. Iaccarino, A. Doostan
{"title":"Bi-fidelity approximation for uncertainty quantification and sensitivity analysis of irradiated particle-laden turbulence.","authors":"Hillary R. Fairbanks, L. Jofre, G. Geraci, G. Iaccarino, A. Doostan","doi":"10.2172/1463950","DOIUrl":"https://doi.org/10.2172/1463950","url":null,"abstract":"Efficiently performing predictive studies of irradiated particle-laden turbulent flows has the potential of providing significant contributions towards better understanding and optimizing, for example, concentrated solar power systems. As there are many uncertainties inherent in such flows, uncertainty quantification is fundamental to improve the predictive capabilities of the numerical simulations. For large-scale, multi-physics problems exhibiting high-dimensional uncertainty, characterizing the stochastic solution presents a significant computational challenge as many methods require a large number of high-fidelity solves. This requirement results in the need for a possibly infeasible number of simulations when a typical converged high-fidelity simulation requires intensive computational resources. To reduce the cost of quantifying high-dimensional uncertainties, we investigate the application of a non-intrusive, bi-fidelity approximation to estimate statistics of quantities of interest associated with an irradiated particle-laden turbulent flow. This method relies on exploiting the low-rank structure of the solution to accelerate the stochastic sampling and approximation processes by means of cheaper-to-run, lower fidelity representations. The application of this bi-fidelity approximation results in accurate estimates of the QoI statistics while requiring a small number of high-fidelity model evaluations.","PeriodicalId":8424,"journal":{"name":"arXiv: Computational Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82869302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 13
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