首页 > 最新文献

Journal of Computational Physics最新文献

英文 中文
Taylor series error correction network for super-resolution of discretized partial differential equation solutions 用于离散化偏微分方程解超分辨率的泰勒级数纠错网络
IF 3.8 2区 物理与天体物理 Q2 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS Pub Date : 2024-11-15 DOI: 10.1016/j.jcp.2024.113569
Wenzhuo Xu, Christopher McComb, Noelia Grande Gutiérrez
High-fidelity engineering simulations can impose an enormous computational burden, hindering their application in design processes or other scenarios where time or computational resources can be limited. An effective up-sampling method for generating high-resolution data can help reduce the computational resources and time required for these simulations. However, conventional up-sampling methods encounter challenges when estimating results based on low-resolution meshes due to the often non-linear behavior of discretization error induced by the coarse mesh. In this study, we present the Taylor Expansion Error Correction Network (TEECNet), a neural network designed to efficiently super-resolve partial differential equations (PDEs) solutions via graph representations. We use a neural network to learn high-dimensional non-linear mappings between low- and high-fidelity solution spaces to approximate the effects of discretization error. The learned mapping is then applied to the low-fidelity solution to obtain an error correction model. Building upon the notion that discretization error can be expressed as a Taylor series expansion based on the mesh size, we directly encode approximations of the numerical error in the network design. This novel approach is capable of correcting point-wise evaluations and emulating physical laws in infinite-dimensional solution spaces. Additionally, results from computational experiments verify that the proposed model exhibits the ability to generalize across diverse physics problems, including heat transfer, Burgers' equation, and cylinder wake flow, achieving over 96% accuracy by mean squared error and a 42.76% reduction in computation cost compared to popular operator regression methods.
高保真工程模拟可能会带来巨大的计算负担,妨碍其在设计过程或其他时间或计算资源有限的情况下的应用。有效的上采样方法可生成高分辨率数据,有助于减少这些模拟所需的计算资源和时间。然而,传统的上采样方法在估计基于低分辨率网格的结果时会遇到挑战,因为粗网格通常会引起离散化误差的非线性行为。在本研究中,我们提出了泰勒扩展误差校正网络(TEECNet),这是一种神经网络,旨在通过图表示高效地超解偏微分方程(PDEs)解。我们利用神经网络学习低保真和高保真解空间之间的高维非线性映射,以近似离散化误差的影响。然后将学习到的映射应用于低保真解,从而获得误差修正模型。基于离散化误差可表示为基于网格大小的泰勒级数展开这一概念,我们在网络设计中直接编码了数值误差的近似值。这种新颖的方法能够在无限维解算空间中修正点式评估并模拟物理规律。此外,计算实验的结果验证了所提出的模型有能力通用于各种物理问题,包括传热、伯格斯方程和气缸尾流,与流行的算子回归方法相比,平均平方误差精度超过 96%,计算成本降低 42.76%。
{"title":"Taylor series error correction network for super-resolution of discretized partial differential equation solutions","authors":"Wenzhuo Xu,&nbsp;Christopher McComb,&nbsp;Noelia Grande Gutiérrez","doi":"10.1016/j.jcp.2024.113569","DOIUrl":"10.1016/j.jcp.2024.113569","url":null,"abstract":"<div><div>High-fidelity engineering simulations can impose an enormous computational burden, hindering their application in design processes or other scenarios where time or computational resources can be limited. An effective up-sampling method for generating high-resolution data can help reduce the computational resources and time required for these simulations. However, conventional up-sampling methods encounter challenges when estimating results based on low-resolution meshes due to the often non-linear behavior of discretization error induced by the coarse mesh. In this study, we present the Taylor Expansion Error Correction Network (TEECNet), a neural network designed to efficiently super-resolve partial differential equations (PDEs) solutions via graph representations. We use a neural network to learn high-dimensional non-linear mappings between low- and high-fidelity solution spaces to approximate the effects of discretization error. The learned mapping is then applied to the low-fidelity solution to obtain an error correction model. Building upon the notion that discretization error can be expressed as a Taylor series expansion based on the mesh size, we directly encode approximations of the numerical error in the network design. This novel approach is capable of correcting point-wise evaluations and emulating physical laws in infinite-dimensional solution spaces. Additionally, results from computational experiments verify that the proposed model exhibits the ability to generalize across diverse physics problems, including heat transfer, Burgers' equation, and cylinder wake flow, achieving over 96% accuracy by mean squared error and a 42.76% reduction in computation cost compared to popular operator regression methods.</div></div>","PeriodicalId":352,"journal":{"name":"Journal of Computational Physics","volume":"521 ","pages":"Article 113569"},"PeriodicalIF":3.8,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142653186","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Registration-based nonlinear model reduction of parametrized aerodynamics problems with applications to transonic Euler and RANS flows 基于注册的参数化空气动力学问题非线性模型缩减,应用于跨音速欧拉流和 RANS 流
IF 3.8 2区 物理与天体物理 Q2 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS Pub Date : 2024-11-15 DOI: 10.1016/j.jcp.2024.113576
Alireza H. Razavi, Masayuki Yano
We develop a registration-based nonlinear model-order reduction (MOR) method for partial differential equations (PDEs) with applications to transonic Euler and Reynolds-averaged Navier–Stokes (RANS) equations in aerodynamics. These PDEs exhibit discontinuous features, namely shocks, whose location depends on problem configuration parameters, and the associated parametric solution manifold exhibits a slowly decaying Kolmogorov N-width. As a result, conventional linear MOR methods, which use linear reduced approximation spaces, do not yield accurate low-dimensional approximations. We present a registration-based nonlinear MOR method to overcome this challenge. Our formulation builds on the following key ingredients: (i) a geometrically transformable parametrized PDE discretization; (ii) localized spline-based parametrized transformations which warp the domain to align discontinuities; (iii) an efficient dilation-based shock sensor and metric to compute optimal transformation parameters; (iv) hyperreduction and online-efficient output-based error estimates; and (v) simultaneous transformation and adaptive finite element training. Compared to existing methods in the literature, our formulation is efficiently scalable to larger problems and is equipped with error estimates and hyperreduction. We demonstrate the effectiveness of the method on two-dimensional inviscid and turbulent flows modeled by the Euler and RANS equations, respectively.
我们针对偏微分方程(PDEs)开发了一种基于注册的非线性模型阶减(MOR)方法,并将其应用于空气动力学中的跨声速欧拉方程和雷诺平均纳维-斯托克斯方程(RANS)。这些偏微分方程具有不连续特征,即冲击,其位置取决于问题的配置参数,相关的参数解流形呈现缓慢衰减的 Kolmogorov N 宽。因此,使用线性缩小近似空间的传统线性 MOR 方法无法获得精确的低维近似。我们提出了一种基于配准的非线性 MOR 方法来克服这一难题。我们的方法基于以下关键要素:(i) 可进行几何变换的参数化 PDE 离散化;(ii) 基于参数化样条的局部变换,对域进行翘曲以对齐不连续性;(iii) 基于扩张的高效冲击传感器和度量,以计算最佳变换参数;(iv) 超还原和基于在线高效输出的误差估计;以及 (v) 同步变换和自适应有限元训练。与文献中的现有方法相比,我们的方法可有效地扩展到更大的问题,并配备了误差估计和超还原功能。我们分别在以欧拉方程和 RANS 方程为模型的二维不粘性流和湍流中演示了该方法的有效性。
{"title":"Registration-based nonlinear model reduction of parametrized aerodynamics problems with applications to transonic Euler and RANS flows","authors":"Alireza H. Razavi,&nbsp;Masayuki Yano","doi":"10.1016/j.jcp.2024.113576","DOIUrl":"10.1016/j.jcp.2024.113576","url":null,"abstract":"<div><div>We develop a registration-based nonlinear model-order reduction (MOR) method for partial differential equations (PDEs) with applications to transonic Euler and Reynolds-averaged Navier–Stokes (RANS) equations in aerodynamics. These PDEs exhibit discontinuous features, namely shocks, whose location depends on problem configuration parameters, and the associated parametric solution manifold exhibits a slowly decaying Kolmogorov <em>N</em>-width. As a result, conventional linear MOR methods, which use linear reduced approximation spaces, do not yield accurate low-dimensional approximations. We present a registration-based nonlinear MOR method to overcome this challenge. Our formulation builds on the following key ingredients: (i) a geometrically transformable parametrized PDE discretization; (ii) localized spline-based parametrized transformations which warp the domain to align discontinuities; (iii) an efficient dilation-based shock sensor and metric to compute optimal transformation parameters; (iv) hyperreduction and online-efficient output-based error estimates; and (v) simultaneous transformation and adaptive finite element training. Compared to existing methods in the literature, our formulation is efficiently scalable to larger problems and is equipped with error estimates and hyperreduction. We demonstrate the effectiveness of the method on two-dimensional inviscid and turbulent flows modeled by the Euler and RANS equations, respectively.</div></div>","PeriodicalId":352,"journal":{"name":"Journal of Computational Physics","volume":"521 ","pages":"Article 113576"},"PeriodicalIF":3.8,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142653061","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Local energy-preserving scalar auxiliary variable approaches for general multi-symplectic Hamiltonian PDEs 一般多交映哈密顿 PDE 的局部能量守恒标量辅助变量方法
IF 3.8 2区 物理与天体物理 Q2 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS Pub Date : 2024-11-14 DOI: 10.1016/j.jcp.2024.113573
Jiaxiang Cai , Yushun Wang
We develop two classes of general-purpose second-order integrators for the general multi-symplectic Hamiltonian system by incorporating a scalar auxiliary variable. Unlike the previous methods introduced in [22], [31], these new approaches do not impose constraints on the state function of multi-symplectic system, and can preserve the original local/global energy conservation laws exactly. Moreover, the approaches are computationally efficient, as they only require solving linear equations with the same constant coefficients at each time step along with some additional scalar nonlinear equations. We employ the proposed methods to solve various equations, and the numerical results validate their solution accuracy, effectiveness, robustness, and energy-preserving ability.
通过加入标量辅助变量,我们为一般多交点哈密顿系统开发了两类通用二阶积分器。与之前在 [22] 和 [31] 中介绍的方法不同,这些新方法不对多交点系统的状态函数施加约束,可以精确地保留原始的局部/全局能量守恒定律。此外,这些方法的计算效率很高,因为它们只需要在每个时间步求解具有相同常数系数的线性方程以及一些额外的标量非线性方程。我们采用所提出的方法求解各种方程,数值结果验证了这些方法的求解精度、有效性、鲁棒性和能量守恒能力。
{"title":"Local energy-preserving scalar auxiliary variable approaches for general multi-symplectic Hamiltonian PDEs","authors":"Jiaxiang Cai ,&nbsp;Yushun Wang","doi":"10.1016/j.jcp.2024.113573","DOIUrl":"10.1016/j.jcp.2024.113573","url":null,"abstract":"<div><div>We develop two classes of general-purpose second-order integrators for the general multi-symplectic Hamiltonian system by incorporating a scalar auxiliary variable. Unlike the previous methods introduced in <span><span>[22]</span></span>, <span><span>[31]</span></span>, these new approaches do not impose constraints on the state function of multi-symplectic system, and can preserve the original local/global energy conservation laws exactly. Moreover, the approaches are computationally efficient, as they only require solving linear equations with the same constant coefficients at each time step along with some additional scalar nonlinear equations. We employ the proposed methods to solve various equations, and the numerical results validate their solution accuracy, effectiveness, robustness, and energy-preserving ability.</div></div>","PeriodicalId":352,"journal":{"name":"Journal of Computational Physics","volume":"521 ","pages":"Article 113573"},"PeriodicalIF":3.8,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142653184","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
ARMS: Adding and removing markers on splines for high-order general interface tracking under the MARS framework ARMS:在 MARS 框架下为高阶一般界面跟踪添加和删除样条上的标记
IF 3.8 2区 物理与天体物理 Q2 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS Pub Date : 2024-11-14 DOI: 10.1016/j.jcp.2024.113574
Difei Hu , Kaiyi Liang , Linjie Ying , Sen Li , Qinghai Zhang
Based on the MARS framework for interface tracking (IT) (Zhang and Fogelson (2016) [33]) (Zhang and Li (2020) [35]), we propose ARMS (adding and removing markers on splines as a strategy for regularizing distances between adjacent markers in simulating moving boundary problems. In ARMS, we represent the interface by cubic/quintic splines and add/remove interface markers at each time step to maintain a roughly uniform distribution of chordal lengths. To demonstrate the utility of ARMS, we apply it to two-dimensional mean curvature flows to develop ARMS-MCF2D, where spatial derivatives are approximated by finite difference formulas and the resulting nonlinear system of ordinary differential equations is solved by explicit, semi-implicit, and implicit Runge–Kutta methods. As such, the semi-implicit and implicit ARMS-MCF2D methods are unconditionally stable. Error analysis indicates that the order of accuracy of ARMS-MCF2D can be 2, 4, or 6. Results of numerical experiments confirm the analysis, show the effectiveness of ARMS in maintaining the regularity of interface markers, and demonstrate the superior accuracy of ARMS-MCF2D over other existing methods. A one-phase Stefan problem is also simulated by coupling ARMS to a finite difference method, exhibiting its potential utility to general IT in moving boundary problems. The generality and flexibility of ARMS partially lie in the fact that, by specifying a discrete time integrator for her own moving boundary problem, an application scientist immediately obtains a MARS method for the problem without worrying about curve fitting and marker distributions.
基于用于界面跟踪(IT)的 MARS 框架(Zhang 和 Fogelson (2016) [33])(Zhang 和 Li (2020) [35]),我们提出了 ARMS(在样条上添加和移除标记,作为在模拟移动边界问题时规整相邻标记间距离的策略)。在 ARMS 中,我们用三次/五次样条表示界面,并在每个时间步添加/移除界面标记,以保持弦长的大致均匀分布。为了证明 ARMS 的实用性,我们将其应用于二维平均曲率流,开发了 ARMS-MCF2D,其中空间导数由有限差分公式近似表示,由此产生的非线性常微分方程系统由显式、半隐式和隐式 Runge-Kutta 方法求解。因此,半隐式和隐式 ARMS-MCF2D 方法是无条件稳定的。误差分析表明,ARMS-MCF2D 的精度阶数可以是 2、4 或 6。数值实验结果证实了上述分析,显示了 ARMS 在保持界面标记规则性方面的有效性,并证明 ARMS-MCF2D 的精度优于其他现有方法。通过将 ARMS 与有限差分法耦合,还模拟了单相斯特凡问题,展示了 ARMS 在移动边界问题中对一般 IT 的潜在实用性。ARMS的通用性和灵活性部分在于,应用科学家只需为自己的移动边界问题指定一个离散时间积分器,就能立即获得该问题的MARS方法,而无需担心曲线拟合和标记分布。
{"title":"ARMS: Adding and removing markers on splines for high-order general interface tracking under the MARS framework","authors":"Difei Hu ,&nbsp;Kaiyi Liang ,&nbsp;Linjie Ying ,&nbsp;Sen Li ,&nbsp;Qinghai Zhang","doi":"10.1016/j.jcp.2024.113574","DOIUrl":"10.1016/j.jcp.2024.113574","url":null,"abstract":"<div><div>Based on the MARS framework for interface tracking (IT) (Zhang and Fogelson (2016) <span><span>[33]</span></span>) (Zhang and Li (2020) <span><span>[35]</span></span>), we propose ARMS (adding and removing markers on splines as a strategy for regularizing distances between adjacent markers in simulating moving boundary problems. In ARMS, we represent the interface by cubic/quintic splines and add/remove interface markers at each time step to maintain a roughly uniform distribution of chordal lengths. To demonstrate the utility of ARMS, we apply it to two-dimensional mean curvature flows to develop ARMS-MCF2D, where spatial derivatives are approximated by finite difference formulas and the resulting nonlinear system of ordinary differential equations is solved by explicit, semi-implicit, and implicit Runge–Kutta methods. As such, the semi-implicit and implicit ARMS-MCF2D methods are unconditionally stable. Error analysis indicates that the order of accuracy of ARMS-MCF2D can be 2, 4, or 6. Results of numerical experiments confirm the analysis, show the effectiveness of ARMS in maintaining the regularity of interface markers, and demonstrate the superior accuracy of ARMS-MCF2D over other existing methods. A one-phase Stefan problem is also simulated by coupling ARMS to a finite difference method, exhibiting its potential utility to general IT in moving boundary problems. The generality and flexibility of ARMS partially lie in the fact that, by specifying a discrete time integrator for her own moving boundary problem, an application scientist immediately obtains a MARS method for the problem without worrying about curve fitting and marker distributions.</div></div>","PeriodicalId":352,"journal":{"name":"Journal of Computational Physics","volume":"521 ","pages":"Article 113574"},"PeriodicalIF":3.8,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142653059","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
A hybrid a posteriori MOOD limited lattice Boltzmann method to solve compressible fluid flows – LBMOOD 解决可压缩流体流动的混合后验 MOOD 有限晶格玻尔兹曼法 - LBMOOD
IF 3.8 2区 物理与天体物理 Q2 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS Pub Date : 2024-11-13 DOI: 10.1016/j.jcp.2024.113570
Ksenia Kozhanova , Song Zhao , Raphaël Loubère , Pierre Boivin
In this paper we blend two lattice-Boltzmann (LB) numerical schemes with an a posteriori Multi-dimensional Optimal Order Detection (MOOD) paradigm to solve hyperbolic systems of conservation laws in 1D and 2D. The first LB scheme is robust to the presence of shock waves but lacks accuracy on smooth flows. The second one has a second-order of accuracy but develops non-physical oscillations when solving steep gradients. The MOOD paradigm produces a hybrid LB scheme via smooth and positivity detectors allowing to gather the best properties of the two LB methods within one scheme. Indeed, the resulting scheme presents second order of accuracy on smooth solutions, essentially non-oscillatory behaviour on irregular ones, and, an ‘almost fail-safe’ property concerning positivity issues. The numerical results on a set of sanity test cases and demanding ones are presented assessing the appropriate behaviour of the hybrid LBMOOD scheme in 1D and 2D.
在本文中,我们将两种格子-玻尔兹曼(LB)数值方案与后验多维最优阶次检测(MOOD)范式相结合,以求解一维和二维的双曲守恒定律系统。第一种 LB 方案对冲击波的存在具有鲁棒性,但对平滑流动缺乏精确性。第二种方案具有二阶精度,但在求解陡峭梯度时会产生非物理振荡。MOOD 范式通过平滑和正向检测器产生了一种混合 LB 方案,从而将两种 LB 方法的最佳特性集于一身。事实上,由此产生的方案在平滑解上具有二阶精度,在不规则解上基本无振荡行为,并且在正向性问题上具有 "几乎万无一失 "的特性。本文介绍了一组理智测试案例和高难度案例的数值结果,以评估混合 LBMOOD 方案在一维和二维中的适当行为。
{"title":"A hybrid a posteriori MOOD limited lattice Boltzmann method to solve compressible fluid flows – LBMOOD","authors":"Ksenia Kozhanova ,&nbsp;Song Zhao ,&nbsp;Raphaël Loubère ,&nbsp;Pierre Boivin","doi":"10.1016/j.jcp.2024.113570","DOIUrl":"10.1016/j.jcp.2024.113570","url":null,"abstract":"<div><div>In this paper we blend two lattice-Boltzmann (LB) numerical schemes with an <em>a posteriori</em> Multi-dimensional Optimal Order Detection (MOOD) paradigm to solve hyperbolic systems of conservation laws in 1D and 2D. The first LB scheme is robust to the presence of shock waves but lacks accuracy on smooth flows. The second one has a second-order of accuracy but develops non-physical oscillations when solving steep gradients. The MOOD paradigm produces a hybrid LB scheme via smooth and positivity detectors allowing to gather the best properties of the two LB methods within one scheme. Indeed, the resulting scheme presents second order of accuracy on smooth solutions, essentially non-oscillatory behaviour on irregular ones, and, an ‘almost fail-safe’ property concerning positivity issues. The numerical results on a set of sanity test cases and demanding ones are presented assessing the appropriate behaviour of the hybrid LBMOOD scheme in 1D and 2D.</div></div>","PeriodicalId":352,"journal":{"name":"Journal of Computational Physics","volume":"521 ","pages":"Article 113570"},"PeriodicalIF":3.8,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142653060","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
On the accuracy of numerical methods for the discretization of anisotropic elliptic problems 关于各向异性椭圆问题离散化数值方法的精度
IF 3.8 2区 物理与天体物理 Q2 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS Pub Date : 2024-11-12 DOI: 10.1016/j.jcp.2024.113568
Chang Yang , Fabrice Deluzet , Jacek Narski
In this paper the loss of precision of numerical methods discretizing anisotropic elliptic problems is analyzed. This feature is prominently observed when the coordinates and the mesh are unrelated to the anisotropy direction. This issue is carefully analyzed and related to the asymptotic instability of the discretizations. The investigations carried out within this paper demonstrate that, high order methods commonly implemented to cope with this difficulty, though bringing evident gains, remain for far from optimal and limited to moderate anisotropy strengths. A second issue, related to the reconstruction of the solution discrete parallel gradients, is also addressed. In particular, it is demonstrated that an accurate approximation can hardly be computed from a precise numerical approximation of the solution. A new method is proposed, consisting in introducing an auxiliary variable providing discrete approximations of the parallel gradient with a precision unrelated to the anisotropy strength.
本文分析了各向异性椭圆问题离散化数值方法的精度损失。当坐标和网格与各向异性方向无关时,就会明显观察到这一特征。本文仔细分析了这一问题,并将其与离散化的渐近不稳定性联系起来。本文进行的研究表明,为解决这一难题而普遍采用的高阶方法虽然带来了明显的收益,但仍远未达到最佳效果,而且仅限于中等各向异性强度。本文还讨论了与离散平行梯度解的重建有关的第二个问题。特别是,研究表明,精确的近似值很难从精确的数值近似解中计算出来。我们提出了一种新方法,即引入一个辅助变量,以与各向异性强度无关的精度提供离散的平行梯度近似值。
{"title":"On the accuracy of numerical methods for the discretization of anisotropic elliptic problems","authors":"Chang Yang ,&nbsp;Fabrice Deluzet ,&nbsp;Jacek Narski","doi":"10.1016/j.jcp.2024.113568","DOIUrl":"10.1016/j.jcp.2024.113568","url":null,"abstract":"<div><div>In this paper the loss of precision of numerical methods discretizing anisotropic elliptic problems is analyzed. This feature is prominently observed when the coordinates and the mesh are unrelated to the anisotropy direction. This issue is carefully analyzed and related to the asymptotic instability of the discretizations. The investigations carried out within this paper demonstrate that, high order methods commonly implemented to cope with this difficulty, though bringing evident gains, remain for far from optimal and limited to moderate anisotropy strengths. A second issue, related to the reconstruction of the solution discrete parallel gradients, is also addressed. In particular, it is demonstrated that an accurate approximation can hardly be computed from a precise numerical approximation of the solution. A new method is proposed, consisting in introducing an auxiliary variable providing discrete approximations of the parallel gradient with a precision unrelated to the anisotropy strength.</div></div>","PeriodicalId":352,"journal":{"name":"Journal of Computational Physics","volume":"521 ","pages":"Article 113568"},"PeriodicalIF":3.8,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142653176","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Ray decomposition radiation transport for high performance computing 用于高性能计算的射线分解辐射传输
IF 3.8 2区 物理与天体物理 Q2 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS Pub Date : 2024-11-12 DOI: 10.1016/j.jcp.2024.113567
Owen Mylotte, Matthew T. McGurn, Kenneth Budzinski, Paul E. DesJardin
Radiation transport is essential in many high-performance computing problems. However, its complexity presents computational challenges. This study presents a novel algorithm, the ray decomposition method for long characteristics transport, designed to address communication challenges specific to distributed memory computing. Reordering of ray property calculations reduces communication cost associated with sequential ray integration. Verification studies demonstrate solution convergence. Performance modeling of the ray decomposition method predicts the compute time from first principles. Consistency of experimentally measured performance with analytical predictions validates the performance scaling model. This work represents a step towards more scalable and efficient radiation transport simulations.
辐射传输在许多高性能计算问题中至关重要。然而,其复杂性给计算带来了挑战。本研究提出了一种新型算法,即用于长特性传输的射线分解法,旨在解决分布式内存计算所特有的通信难题。射线特性计算的重新排序降低了与顺序射线整合相关的通信成本。验证研究证明了解决方案的收敛性。射线分解方法的性能建模根据第一原理预测了计算时间。实验测量的性能与分析预测的一致性验证了性能扩展模型。这项工作标志着向更可扩展、更高效的辐射传输模拟迈出了一步。
{"title":"Ray decomposition radiation transport for high performance computing","authors":"Owen Mylotte,&nbsp;Matthew T. McGurn,&nbsp;Kenneth Budzinski,&nbsp;Paul E. DesJardin","doi":"10.1016/j.jcp.2024.113567","DOIUrl":"10.1016/j.jcp.2024.113567","url":null,"abstract":"<div><div>Radiation transport is essential in many high-performance computing problems. However, its complexity presents computational challenges. This study presents a novel algorithm, the ray decomposition method for long characteristics transport, designed to address communication challenges specific to distributed memory computing. Reordering of ray property calculations reduces communication cost associated with sequential ray integration. Verification studies demonstrate solution convergence. Performance modeling of the ray decomposition method predicts the compute time from first principles. Consistency of experimentally measured performance with analytical predictions validates the performance scaling model. This work represents a step towards more scalable and efficient radiation transport simulations.</div></div>","PeriodicalId":352,"journal":{"name":"Journal of Computational Physics","volume":"521 ","pages":"Article 113567"},"PeriodicalIF":3.8,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142653183","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Stability and robustness of time-discretization schemes for the Allen-Cahn equation via bifurcation and perturbation analysis 通过分岔和扰动分析看艾伦-卡恩方程时间离散化方案的稳定性和稳健性
IF 3.8 2区 物理与天体物理 Q2 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS Pub Date : 2024-11-08 DOI: 10.1016/j.jcp.2024.113565
Wenrui Hao , Sun Lee , Xiaofeng Xu , Zhiliang Xu
The Allen-Cahn equation is a fundamental model for phase transitions, offering critical insights into the dynamics of interface evolution in various physical systems. This paper investigates the stability and robustness of frequently utilized time-discretization numerical schemes for solving the Allen-Cahn equation, with focuses on the Backward Euler, Crank-Nicolson (CN), convex splitting of modified CN, and Diagonally Implicit Runge-Kutta (DIRK) methods. Our stability analysis reveals that the Convex Splitting of the Modified CN scheme exhibits unconditional stability, allowing greater flexibility in time step size selection, while the other schemes are conditionally stable. Additionally, our robustness analysis highlights that the Backward Euler method converges to correct physical solutions regardless of initial conditions. In contrast, all other methods studied in this work show sensitivity to initial conditions and may converge to incorrect physical solutions if the initial conditions are not carefully chosen. This study introduces a comprehensive approach to assessing stability and robustness in numerical methods for solving the Allen-Cahn equation, providing a new perspective for evaluating numerical techniques for general nonlinear differential equations.
Allen-Cahn 方程是相变的基本模型,为了解各种物理系统中界面演变的动力学提供了重要见解。本文研究了求解 Allen-Cahn 方程时常用的时间离散化数值方案的稳定性和鲁棒性,重点研究了后向欧拉法、Crank-Nicolson (CN)、修正 CN 的凸分割法和对角隐式 Runge-Kutta (DIRK) 方法。我们的稳定性分析表明,修正 CN 方案的凸分裂表现出无条件稳定性,允许更灵活地选择时间步长,而其他方案则表现出条件稳定性。此外,我们的鲁棒性分析强调,无论初始条件如何,后向欧拉法都能收敛到正确的物理解。相比之下,本文研究的所有其他方法都显示出对初始条件的敏感性,如果不仔细选择初始条件,可能会收敛到不正确的物理解。这项研究引入了一种全面的方法来评估求解 Allen-Cahn 方程的数值方法的稳定性和鲁棒性,为评估一般非线性微分方程的数值技术提供了一个新的视角。
{"title":"Stability and robustness of time-discretization schemes for the Allen-Cahn equation via bifurcation and perturbation analysis","authors":"Wenrui Hao ,&nbsp;Sun Lee ,&nbsp;Xiaofeng Xu ,&nbsp;Zhiliang Xu","doi":"10.1016/j.jcp.2024.113565","DOIUrl":"10.1016/j.jcp.2024.113565","url":null,"abstract":"<div><div>The Allen-Cahn equation is a fundamental model for phase transitions, offering critical insights into the dynamics of interface evolution in various physical systems. This paper investigates the stability and robustness of frequently utilized time-discretization numerical schemes for solving the Allen-Cahn equation, with focuses on the Backward Euler, Crank-Nicolson (CN), convex splitting of modified CN, and Diagonally Implicit Runge-Kutta (DIRK) methods. Our stability analysis reveals that the Convex Splitting of the Modified CN scheme exhibits unconditional stability, allowing greater flexibility in time step size selection, while the other schemes are conditionally stable. Additionally, our robustness analysis highlights that the Backward Euler method converges to correct physical solutions regardless of initial conditions. In contrast, all other methods studied in this work show sensitivity to initial conditions and may converge to incorrect physical solutions if the initial conditions are not carefully chosen. This study introduces a comprehensive approach to assessing stability and robustness in numerical methods for solving the Allen-Cahn equation, providing a new perspective for evaluating numerical techniques for general nonlinear differential equations.</div></div>","PeriodicalId":352,"journal":{"name":"Journal of Computational Physics","volume":"521 ","pages":"Article 113565"},"PeriodicalIF":3.8,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142653179","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Gradient-boosted spatiotemporal neural network for simulating underground hydrogen storage in aquifers 用于模拟含水层地下储氢的梯度提升时空神经网络
IF 3.8 2区 物理与天体物理 Q2 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS Pub Date : 2024-11-08 DOI: 10.1016/j.jcp.2024.113557
Jian Wang , Zongwen Hu , Xia Yan , Jun Yao , Hai Sun , Yongfei Yang , Lei Zhang , Junjie Zhong
Underground hydrogen storage (UHS) in aquifers has emerged as a viable solution to address the seasonal mismatch between supply and demand in renewable energy. Numerical simulation of the UHS serves as a crucial foundation for optimizing storage operations and conducting system risk assessments. However, numerical simulation methods employed for these purposes often demand substantial data, making data collection challenging and computationally expensive, especially in scenarios involving the coupling of multiple physical fields. Deep learning serves as an effective tool in resolving this challenge. Here, we proposed a spatiotemporal neural network architecture with gradient enhancement, denoted as gradient-boosted spatiotemporal neural network (GSTNN) and its variant GSTNN-s. The GSTNN combines a convolutional neural network (CNN), a long short-term memory network (LSTM), and an autoencoder architecture. To incorporate physical constraints into the network, the spatiotemporal gradient operators from the gas-water seepage and gas convection-diffusion equations are introduced as regularization terms, imposing physics-informed constraints on the training process in both temporal and spatial dimensions. In predicting the multiphase flow of UHS in both homogeneous and heterogeneous formations, GSTNN outperforms CNN and CNN-LSTM in terms of the accuracy of pressure, saturation and H2 concentration fields. In terms of predicting UHS in formations with different permeabilities and porosities, GSTNN-s demonstrates improved performance as well. The proposed GSTNN architecture is promising in improving the efficiency of UHS numerical simulation, and has great potential to be applied for optimizing UHS operations in the future.
含水层地下储氢(UHS)已成为解决可再生能源季节性供需不匹配问题的可行方案。地下储氢系统的数值模拟是优化储氢操作和进行系统风险评估的重要基础。然而,用于这些目的的数值模拟方法通常需要大量数据,这使得数据收集具有挑战性且计算成本高昂,尤其是在涉及多个物理场耦合的情况下。深度学习是解决这一难题的有效工具。在此,我们提出了一种具有梯度增强功能的时空神经网络架构,称为梯度增强时空神经网络(GSTNN)及其变体 GSTNN-s。GSTNN 结合了卷积神经网络(CNN)、长短期记忆网络(LSTM)和自动编码器架构。为了在网络中加入物理约束,引入了气体-水渗流方程和气体对流-扩散方程中的时空梯度算子作为正则项,在时间和空间维度上对训练过程施加物理约束。在预测同质和异质地层中 UHS 的多相流时,GSTNN 在压力场、饱和度场和 H2 浓度场的精度方面均优于 CNN 和 CNN-LSTM。在预测不同渗透率和孔隙度地层中的 UHS 方面,GSTNN-s 的性能也有所提高。所提出的 GSTNN 架构有望提高 UHS 数值模拟的效率,在未来应用于优化 UHS 操作方面具有巨大潜力。
{"title":"Gradient-boosted spatiotemporal neural network for simulating underground hydrogen storage in aquifers","authors":"Jian Wang ,&nbsp;Zongwen Hu ,&nbsp;Xia Yan ,&nbsp;Jun Yao ,&nbsp;Hai Sun ,&nbsp;Yongfei Yang ,&nbsp;Lei Zhang ,&nbsp;Junjie Zhong","doi":"10.1016/j.jcp.2024.113557","DOIUrl":"10.1016/j.jcp.2024.113557","url":null,"abstract":"<div><div>Underground hydrogen storage (UHS) in aquifers has emerged as a viable solution to address the seasonal mismatch between supply and demand in renewable energy. Numerical simulation of the UHS serves as a crucial foundation for optimizing storage operations and conducting system risk assessments. However, numerical simulation methods employed for these purposes often demand substantial data, making data collection challenging and computationally expensive, especially in scenarios involving the coupling of multiple physical fields. Deep learning serves as an effective tool in resolving this challenge. Here, we proposed a spatiotemporal neural network architecture with gradient enhancement, denoted as gradient-boosted spatiotemporal neural network (GSTNN) and its variant GSTNN-s. The GSTNN combines a convolutional neural network (CNN), a long short-term memory network (LSTM), and an autoencoder architecture. To incorporate physical constraints into the network, the spatiotemporal gradient operators from the gas-water seepage and gas convection-diffusion equations are introduced as regularization terms, imposing physics-informed constraints on the training process in both temporal and spatial dimensions. In predicting the multiphase flow of UHS in both homogeneous and heterogeneous formations, GSTNN outperforms CNN and CNN-LSTM in terms of the accuracy of pressure, saturation and H<sub>2</sub> concentration fields. In terms of predicting UHS in formations with different permeabilities and porosities, GSTNN-s demonstrates improved performance as well. The proposed GSTNN architecture is promising in improving the efficiency of UHS numerical simulation, and has great potential to be applied for optimizing UHS operations in the future.</div></div>","PeriodicalId":352,"journal":{"name":"Journal of Computational Physics","volume":"521 ","pages":"Article 113557"},"PeriodicalIF":3.8,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142653181","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Stiefel manifold interpolation for non-intrusive model reduction of parameterized fluid flow problems 用于参数化流体流动问题非侵入式模型缩减的 Stiefel 流形插值法
IF 3.8 2区 物理与天体物理 Q2 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS Pub Date : 2024-11-07 DOI: 10.1016/j.jcp.2024.113564
Achraf El Omari , Mohamed El Khlifi , Laurent Cordier
Many engineering problems are parameterized. In order to minimize the computational cost necessary to evaluate a new operating point, the interpolation of singular matrices representing the data seems natural. Unfortunately, interpolating such data by conventional methods usually leads to unphysical solutions, as the data live on manifolds and not vector spaces. An alternative is to perform the interpolation in the tangent space to the Grassmann manifold to obtain interpolated spatial modes. Temporal modes are afterwards determined via the Galerkin projection of the high-fidelity model onto the interpolated spatial basis. This method, which is known for some fifteen years, is intrusive. Recently, Oulghelou and Allery (JCP, 2021) have proposed a non-intrusive approach (equation-free), but requiring the resolution of two low-dimensional optimization problems after interpolation. In this paper, a non-intrusive alternative based on Interpolation on the Tangent Space of the Stiefel Manifold (ITSSM) is presented. This approach has the advantage of not requiring a calibration phase after interpolation. To assess the method, we compare our results with those obtained using global POD on the one hand, and two methods based on Grassmann interpolation on the other. These comparisons are performed for two classical configurations encountered in fluid dynamics. The first corresponds to the one-dimensional non-linear Burgers' equation. The second example is the two-dimensional cylinder wake flow. We show that the proposed strategy can accurately reconstruct the physical quantities associated with a new operating point. Moreover, the estimation is fast enough to allow real-time computation.
许多工程问题都是参数化的。为了最大限度地降低评估新工作点所需的计算成本,对代表数据的奇异矩阵进行插值似乎很自然。遗憾的是,用传统方法对这些数据进行插值通常会导致非物理解,因为数据是在流形而非矢量空间中存在的。另一种方法是在格拉斯曼流形的切线空间进行插值,以获得插值空间模式。然后,通过将高保真模型投影到插值空间基础上的伽勒金投影来确定时间模式。这种方法已有 15 年历史,但具有侵入性。最近,Oulghelou 和 Allery(JCP,2021 年)提出了一种非侵入式方法(无方程),但需要在插值后解决两个低维优化问题。本文提出了一种基于 Stiefel Manifold 切空间插值(ITSSM)的非侵入式替代方法。这种方法的优点是插值后不需要校准阶段。为了对该方法进行评估,我们将我们的结果与使用全局 POD 和基于格拉斯曼插值的两种方法得出的结果进行了比较。这些比较是针对流体力学中遇到的两种经典配置进行的。第一个是一维非线性布尔格斯方程。第二个例子是二维圆柱体尾流。我们发现,所提出的策略可以准确地重建与新工作点相关的物理量。此外,估算速度快,可以进行实时计算。
{"title":"Stiefel manifold interpolation for non-intrusive model reduction of parameterized fluid flow problems","authors":"Achraf El Omari ,&nbsp;Mohamed El Khlifi ,&nbsp;Laurent Cordier","doi":"10.1016/j.jcp.2024.113564","DOIUrl":"10.1016/j.jcp.2024.113564","url":null,"abstract":"<div><div>Many engineering problems are parameterized. In order to minimize the computational cost necessary to evaluate a new operating point, the interpolation of singular matrices representing the data seems natural. Unfortunately, interpolating such data by conventional methods usually leads to unphysical solutions, as the data live on manifolds and not vector spaces. An alternative is to perform the interpolation in the tangent space to the Grassmann manifold to obtain interpolated spatial modes. Temporal modes are afterwards determined via the Galerkin projection of the high-fidelity model onto the interpolated spatial basis. This method, which is known for some fifteen years, is intrusive. Recently, Oulghelou and Allery (JCP, 2021) have proposed a non-intrusive approach (equation-free), but requiring the resolution of two low-dimensional optimization problems after interpolation. In this paper, a non-intrusive alternative based on Interpolation on the Tangent Space of the Stiefel Manifold (ITSSM) is presented. This approach has the advantage of not requiring a calibration phase after interpolation. To assess the method, we compare our results with those obtained using global POD on the one hand, and two methods based on Grassmann interpolation on the other. These comparisons are performed for two classical configurations encountered in fluid dynamics. The first corresponds to the one-dimensional non-linear Burgers' equation. The second example is the two-dimensional cylinder wake flow. We show that the proposed strategy can accurately reconstruct the physical quantities associated with a new operating point. Moreover, the estimation is fast enough to allow real-time computation.</div></div>","PeriodicalId":352,"journal":{"name":"Journal of Computational Physics","volume":"521 ","pages":"Article 113564"},"PeriodicalIF":3.8,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660003","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
期刊
Journal of Computational Physics
全部 Acc. Chem. Res. ACS Applied Bio Materials ACS Appl. Electron. Mater. ACS Appl. Energy Mater. ACS Appl. Mater. Interfaces ACS Appl. Nano Mater. ACS Appl. Polym. Mater. ACS BIOMATER-SCI ENG ACS Catal. ACS Cent. Sci. ACS Chem. Biol. ACS Chemical Health & Safety ACS Chem. Neurosci. ACS Comb. Sci. ACS Earth Space Chem. ACS Energy Lett. ACS Infect. Dis. ACS Macro Lett. ACS Mater. Lett. ACS Med. Chem. Lett. ACS Nano ACS Omega ACS Photonics ACS Sens. ACS Sustainable Chem. Eng. ACS Synth. Biol. Anal. Chem. BIOCHEMISTRY-US Bioconjugate Chem. BIOMACROMOLECULES Chem. Res. Toxicol. Chem. Rev. Chem. Mater. CRYST GROWTH DES ENERG FUEL Environ. Sci. Technol. Environ. Sci. Technol. Lett. Eur. J. Inorg. Chem. IND ENG CHEM RES Inorg. Chem. J. Agric. Food. Chem. J. Chem. Eng. Data J. Chem. Educ. J. Chem. Inf. Model. J. Chem. Theory Comput. J. Med. Chem. J. Nat. Prod. J PROTEOME RES J. Am. Chem. Soc. LANGMUIR MACROMOLECULES Mol. Pharmaceutics Nano Lett. Org. Lett. ORG PROCESS RES DEV ORGANOMETALLICS J. Org. Chem. J. Phys. Chem. J. Phys. Chem. A J. Phys. Chem. B J. Phys. Chem. C J. Phys. Chem. Lett. Analyst Anal. Methods Biomater. Sci. Catal. Sci. Technol. Chem. Commun. Chem. Soc. Rev. CHEM EDUC RES PRACT CRYSTENGCOMM Dalton Trans. Energy Environ. Sci. ENVIRON SCI-NANO ENVIRON SCI-PROC IMP ENVIRON SCI-WAT RES Faraday Discuss. Food Funct. Green Chem. Inorg. Chem. Front. Integr. Biol. J. Anal. At. Spectrom. J. Mater. Chem. A J. Mater. Chem. B J. Mater. Chem. C Lab Chip Mater. Chem. Front. Mater. Horiz. MEDCHEMCOMM Metallomics Mol. Biosyst. Mol. Syst. Des. Eng. Nanoscale Nanoscale Horiz. Nat. Prod. Rep. New J. Chem. Org. Biomol. Chem. Org. Chem. Front. PHOTOCH PHOTOBIO SCI PCCP Polym. Chem.
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
0
微信
客服QQ
Book学术公众号 扫码关注我们
反馈
×
意见反馈
请填写您的意见或建议
请填写您的手机或邮箱
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
现在去查看 取消
×
提示
确定
Book学术官方微信
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术
文献互助 智能选刊 最新文献 互助须知 联系我们:info@booksci.cn
Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。
Copyright © 2023 Book学术 All rights reserved.
ghs 京公网安备 11010802042870号 京ICP备2023020795号-1