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A weaker adversarial neural networks method for linear second order elliptic PDEs 线性二阶椭圆偏微分方程的弱对抗神经网络方法
IF 2.5 2区 数学 Q1 MATHEMATICS, APPLIED Pub Date : 2025-11-13 DOI: 10.1016/j.camwa.2025.11.004
Zhizhong Kong , Rui Sheng , Jerry Zhijian Yang , Juntao You , Cheng Yuan
In this paper, we propose the Weaker Adversarial Network (WerAN), a novel extension of the Weak Adversarial Network (WAN) framework designed for partial differential equations with singularities. By applying integration by parts twice in the derivation of weak form, our approach relaxes the constraints on the solution space in WAN. This adjustment transitions the implementation-level requirements from H1 to L2 and the theoretical requirements from W2, to W1,. Furthermore, we provide a systematic error analysis of the proposed method. Our theoretical investigations affirm the convergence of the WerAN method and offer insights into selecting network parameters and sample sizes across the domain and its boundary. We also present several numerical examples to demonstrate the effectiveness of WerAN in addressing both smooth and singular problems.
在本文中,我们提出了弱对抗网络(WerAN),这是弱对抗网络(WAN)框架的一个新的扩展,该框架是为具有奇异性的偏微分方程设计的。通过在弱形式的推导中两次应用分部积分,我们的方法放宽了广域网中解空间的约束。这一调整将实现层需求从H1转变为L2,理论需求从W2,∞转变为W1,∞。此外,我们还对所提出的方法进行了系统误差分析。我们的理论研究证实了WerAN方法的收敛性,并为跨域及其边界选择网络参数和样本大小提供了见解。我们还给出了几个数值例子来证明WerAN在解决光滑和奇异问题方面的有效性。
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引用次数: 0
Pinning phenomena in numerical schemes of the Allen–Cahn equation Allen-Cahn方程数值格式中的钉钉现象
IF 2.5 2区 数学 Q1 MATHEMATICS, APPLIED Pub Date : 2025-11-12 DOI: 10.1016/j.camwa.2025.11.001
Junseok Kim , Zhengang Li , Xinpei Wu , Soobin Kwak
In this study, we investigate the artificial pinning phenomena that emerge in numerical simulations of high-order Allen–Cahn (AC) equations. The AC equation is widely used to describe interface motion during phase separation processes. However, discretized numerical solutions may exhibit nonphysical behavior such as interface immobilization, or “pinning,” particularly when the ratio between the interfacial thickness model parameter (ϵ) and the spatial numerical mesh size (h) is below a critical threshold. The present work systematically analyzes how this ratio, P=ϵ/h, influences interface dynamics and determines the critical values at which pinning begins to occur for various nonlinearity degrees (α) of the polynomial potential. A fully explicit finite difference method is used to simulate the AC equation in both two- and three-dimensional settings. A bisection algorithm is introduced to accurately identify the critical pinning threshold P as a function of α. Numerical experiments demonstrate that as α increases, P decreases, indicating that the solution becomes more sensitive to spatial discretization and requires finer grids to avoid artificial pinning. Additionally, computational results show that higher values of α yield thicker and smoother interface transitions, and the study also investigates the influence of these values on phase morphology under random initial conditions. The numerical results in this study provide quantitative guidance for selecting discretization parameters in phase-field simulations and emphasize the importance of balancing the interface resolution with model complexity. These insights contribute to the development of accurate and robust numerical schemes for simulating interfacial dynamics in complex physical systems.
在本研究中,我们研究了高阶Allen-Cahn (AC)方程数值模拟中出现的人为钉住现象。交流方程被广泛用于描述相分离过程中的界面运动。然而,离散数值解可能表现出非物理行为,如界面固定或“钉住”,特别是当界面厚度模型参数(柱)与空间数值网格尺寸(h)之间的比率低于临界阈值时。本研究系统地分析了这个比值P= λ /h如何影响界面动力学,并确定了多项式电位的各种非线性度(α)开始发生钉住的临界值。采用全显式有限差分法模拟了二维和三维环境下的交流方程。引入了一种对分算法,以准确地识别临界钉住阈值P作为α的函数。数值实验表明,随着α的增加,P - P - P减小,表明溶液对空间离散化更加敏感,需要更细的网格来避免人为钉住。此外,计算结果表明,α值越高,界面转变越厚、越光滑,并研究了随机初始条件下α值对相形态的影响。本研究的数值结果为相场模拟中离散化参数的选择提供了定量指导,并强调了平衡界面分辨率与模型复杂性的重要性。这些见解有助于开发精确和强大的数值方案来模拟复杂物理系统中的界面动力学。
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引用次数: 0
Discontinuous Galerkin finite element method for a fourth order parabolic variational inequality 一类四阶抛物型变分不等式的不连续Galerkin有限元法
IF 2.5 2区 数学 Q1 MATHEMATICS, APPLIED Pub Date : 2025-11-11 DOI: 10.1016/j.camwa.2025.11.002
Kamana Porwal, Ritesh Singla
In this article, we propose and analyze a discontinuous Galerkin finite element method for the numerical approximation of a fourth-order parabolic variational inequality. In the fully-discrete discontinuous Galerkin scheme, we implement time discretization using the implicit backward Euler method, while spatial discretization is achieved through the utilization of a piecewise quadratic finite element space. The convergence analysis is conducted under a reasonable regularity assumption on the exact solution u, to be specific we assume utL2(0,S;L2(Ω)), and the obstacle constraints are incorporated at the vertices of the triangulation. We derive an optimal order (with respect to the regularity) apriori error estimate in the energy norm. Additionally, we present some numerical experiment results to illustrate the performance of the proposed method.
本文提出并分析了四阶抛物型变分不等式数值逼近的不连续Galerkin有限元法。在完全离散的不连续Galerkin格式中,我们使用隐式后向欧拉方法实现时间离散,而利用分段二次元有限元空间实现空间离散。收敛性分析是在对精确解u的合理正则性假设下进行的,即假设ut∈L2(0,S;L2(Ω)),并在三角剖分的顶点处加入障碍物约束。我们在能量范数中推导出一个最优阶(相对于正则性)先验误差估计。此外,我们还给出了一些数值实验结果来说明所提出方法的性能。
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引用次数: 0
Meshless approach for solving nonlinear time-fractional fourth-order reaction–diffusion equation with convergence order analysis and stability analysis 求解非线性时间分数阶反应扩散方程的无网格方法及收敛阶分析和稳定性分析
IF 2.5 2区 数学 Q1 MATHEMATICS, APPLIED Pub Date : 2025-11-07 DOI: 10.1016/j.camwa.2025.10.024
JiangShan Tong, Zhong Chen, Wei Jiang
This article presents a novel meshless approach to solve a nonlinear fourth-order reaction-diffusion equation with the time-fractional derivative of Caputo-type on arbitrary bounded domains by constructing a set of novel basis using the Sinc function as a shape function with higher accuracy and stability. The key contributions and innovations of this study are summarized as follows. Firstly, the time non-smooth problem is addressed by discretizing time term and approximating the time-fractional derivative with the piecewise fractional linear interpolation. What's more, a novel approach has been developed for the superconvergence estimation of the two-dimensional Sinc function approximation. Subsequently, the time-iterative stability analysis of the semi-analytical solution is presented, and it is demonstrated that the solution is absolutely stable on arbitrary bounded domains. We then present a detailed analysis of both local and global error estimates and prove that the space-time convergence order is O(M4mq+q) with M being the number of basis and q being the length of time step, that is, the spatial convergence order is superconvergent. At last, a series of numerical examples validates the effectiveness of the proposed meshless method, and the low CPU time demonstrates its high computational efficiency.
本文提出了一种在任意有界域上求解具有时间分数阶导数的非线性四阶caputo型反应扩散方程的无网格新方法,该方法采用Sinc函数作为形状函数构造一组新的基,具有较高的精度和稳定性。本研究的主要贡献和创新点总结如下:首先,通过离散时间项和分段分数阶线性插值逼近时间分数阶导数来解决时间非光滑问题;此外,还提出了一种二维Sinc函数逼近的超收敛估计方法。随后,给出了半解析解的时间迭代稳定性分析,证明了该解在任意有界区域上是绝对稳定的。然后对局部误差估计和全局误差估计进行了详细的分析,证明了其时空收敛阶为O(M4−mq+q),其中M为基数,q为时间步长,即空间收敛阶为超收敛阶。最后,通过一系列数值算例验证了所提无网格方法的有效性,较低的CPU时间证明了其较高的计算效率。
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引用次数: 0
Local discontinuous Galerkin method for Kelvin-Voigt viscoelastic fluid flow model Kelvin-Voigt粘弹性流体流动模型的局部不连续Galerkin方法
IF 2.5 2区 数学 Q1 MATHEMATICS, APPLIED Pub Date : 2025-11-03 DOI: 10.1016/j.camwa.2025.10.025
Debendra Kumar Swain , Saumya Bajpai , Deepjyoti Goswami
In this study, we propose and examine a local discontinuous Galerkin finite element approach for solving the Kelvin-Voigt viscoelastic fluid flow equations, incorporating a forcing term within the L2(Ω) space for t>0. The method employs an upwind scheme to efficiently manage the nonlinear convective term. We establish new a priori bounds for the semidiscrete local discontinuous Galerkin approximations. Furthermore, we derive optimal a priori error estimates for the semidiscrete discontinuous Galerkin velocity approximation in L2-norm and the pressure approximation in L2-norm for t>0. Assuming the smallness of the data, we also prove uniform error estimates in time. Additionally, we consider the first- and second-order backward difference schemes for full discretization and derive the corresponding fully discrete error estimates. Finally, numerical experiments are presented to support the theoretical findings.
在这项研究中,我们提出并检验了求解Kelvin-Voigt粘弹性流体流动方程的局部不连续Galerkin有限元方法,该方法在L2(Ω)空间中包含了t>;0的强迫项。该方法采用逆风格式,有效地处理了非线性对流项。建立了半离散局部不连续伽辽金近似的一个新的先验界。此外,对于t>;0的半离散不连续Galerkin速度近似l2范数和压力近似l2范数,我们给出了最优先验误差估计。假设数据较小,我们也证明了一致的时间误差估计。此外,我们考虑了完全离散化的一阶和二阶后向差分格式,并推导了相应的完全离散误差估计。最后,通过数值实验对理论结果进行了验证。
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引用次数: 0
Transient numerical simulation of control valve flow characteristics using a wall function and local grid refinement in LES-LBM 基于壁面函数和局部网格细化的LES-LBM控制阀流动特性瞬态数值模拟
IF 2.5 2区 数学 Q1 MATHEMATICS, APPLIED Pub Date : 2025-11-03 DOI: 10.1016/j.camwa.2025.10.026
Xiang Li , Du Zhou , Zihan Liu , Chao Xu , Likuan Chen , Bingliang Yan , Chuanjiang Shen , Zhixiong Wang , Henghu Yang , Yongzhi Zhao
Transient simulations offer the advantage of capturing time-dependent flow behavior, making them more suitable than steady simulations for modeling complex phenomena such as turbulence, vibration, cavitation, and noise. While traditional CFD methods are more suitable for handling steady simulations, they are less effective for transient simulations due to limited parallel processing capabilities, leading to high computational costs. As a result, the lattice Boltzmann method (LBM) is employed in this study, which is a more efficient approach for transient simulation owing to its efficient handling of complex geometries, programming simplicity, and strong parallel scalability. In order to enhance the stability of LBM in the numerical simulation of high Reynolds number flow fields, the multiple relaxation time (MRT) collision model and the Smagorinsky-Lilly large eddy simulation (LES) turbulence model are utilized. To address the high dissipation near the wall in the Lilly model, the van Driest damping function is incorporated, improving the accuracy of the LES model in boundary regions. Additionally, to minimize memory consumption and reduce computation time without sacrificing accuracy, wall functions and local grid refinement techniques are applied, reducing the overall number of computational grids required. An experimental platform was established to measure the flow characteristics of control valves, and the accuracy of the proposed method was validated by comparing the flow coefficient Cv at various valve openings. Finally, the effects of local grid refinement and wall functions on simulation accuracy were compared, demonstrating that these techniques significantly improve the precision of transient simulations.
瞬态模拟提供了捕获随时间变化的流动行为的优势,使它们比稳定模拟更适合于模拟复杂现象,如湍流、振动、空化和噪声。虽然传统的CFD方法更适合处理稳态模拟,但由于并行处理能力有限,其对瞬态模拟的效果较差,导致计算成本较高。因此,本文采用晶格玻尔兹曼方法(lattice Boltzmann method, LBM)进行瞬态仿真,该方法具有处理复杂几何图形的效率高、编程简单、并行可扩展性强等优点。为了提高LBM在高雷诺数流场数值模拟中的稳定性,采用了多重松弛时间(MRT)碰撞模型和Smagorinsky-Lilly大涡模拟(LES)湍流模型。为解决Lilly模型壁面附近高耗散的问题,引入了van Driest阻尼函数,提高了边界区域LES模型的精度。此外,为了在不牺牲精度的情况下最小化内存消耗和减少计算时间,应用了墙函数和局部网格细化技术,减少了所需计算网格的总数。建立了测量控制阀流量特性的实验平台,通过比较不同开度下的流量系数Cv,验证了所提方法的准确性。最后,比较了局部网格细化和壁面函数对仿真精度的影响,结果表明,这些技术显著提高了瞬态仿真的精度。
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引用次数: 0
A posteriori error estimates for hp-FE discretizations in elastoplasticity 弹塑性中hp-FE离散化的后验误差估计
IF 2.5 2区 数学 Q1 MATHEMATICS, APPLIED Pub Date : 2025-10-30 DOI: 10.1016/j.camwa.2025.10.019
Patrick Bammer, Lothar Banz, Andreas Schröder
In this paper, a reliable a posteriori error estimator for a model problem of elastoplasticity with linearly kinematic hardening is derived, which satisfies some (local) efficiency estimates. It is applicable to any discretization that is conforming with respect to the displacement field and the plastic strain. Furthermore, the paper presents hp-finite element discretizations relying on a variational inequality as well as on a mixed variational formulation and discusses their equivalence by using biorthogonal basis functions. Numerical experiments demonstrate the applicability of the theoretical findings and underline the potential of h- and hp-adaptive finite element discretizations for problems of elastoplasticity.
本文导出了具有线性运动硬化的弹塑性模型问题的可靠后验误差估计量,它满足一些(局部)效率估计。它适用于位移场与塑性应变相符合的任何离散化。此外,本文给出了基于变分不等式和混合变分公式的有限元离散化,并利用双正交基函数讨论了它们的等价性。数值实验证明了理论结果的适用性,并强调了h-和hp-自适应有限元离散化在弹塑性问题中的潜力。
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引用次数: 0
Study on solving partial differential equations governing steady point current source field using M-RPIM 用M-RPIM求解稳态点电流源场偏微分方程的研究
IF 2.5 2区 数学 Q1 MATHEMATICS, APPLIED Pub Date : 2025-10-30 DOI: 10.1016/j.camwa.2025.10.017
Yuhao Zhang , Haifei Liu , Xiaoqiang Li , Yingjie Zhao , Jianxin Liu
This paper proposes the modified radial point interpolation method (M-RPIM) for solving the partial differential equations governing steady point current source fields. Unlike conventional RPIM, M-RPIM constructs support domains based on a cell, only one matrix inversion operation is needed when computing the shape functions in a integration cell, thereby improving computational efficiency. It determines the support domain by searching for neighboring cells layer by layer from the integration domain outward and controls the support domain range by adjusting the search depth. A systematic investigation of search depth effects on M-RPIM shape functions is conducted in this work. Numerical analysis demonstrates that the computational time of M-RPIM increases exponentially as the search depth increases, whereas the solution accuracy does not necessarily enhance. This work proves that M-RPIM with a search depth of 2 or 3 (employing approximately 15 support points) provides effective solutions for the partial differential equations governing steady point current source fields. When selecting a proper search depth, M-RPIM exhibits superior stability and accuracy compared to linear FEM, especially when dealing with complex geological models.
本文提出了一种改进的径向点插值法(M-RPIM),用于求解稳定点源场的偏微分方程。与传统的RPIM不同,M-RPIM基于单元构建支持域,在计算一个积分单元中的形状函数时只需进行一次矩阵反演运算,从而提高了计算效率。从积分域向外逐层搜索相邻单元,确定支持域,并通过调整搜索深度控制支持域的范围。本文系统研究了搜索深度对M-RPIM形状函数的影响。数值分析表明,随着搜索深度的增加,M-RPIM算法的计算时间呈指数增长,而解的精度并不一定提高。本文证明了搜索深度为2或3(使用大约15个支撑点)的M-RPIM为控制稳态点电流源场的偏微分方程提供了有效的解。在选择合适的搜索深度时,与线性有限元法相比,M-RPIM具有更好的稳定性和精度,特别是在处理复杂的地质模型时。
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引用次数: 0
Solving transient heat conduction problems through the direct interpolation technique 利用直接插值技术求解瞬态热传导问题
IF 2.5 2区 数学 Q1 MATHEMATICS, APPLIED Pub Date : 2025-10-28 DOI: 10.1016/j.camwa.2025.10.013
Carlos Friedrich Loeffler , Jose Ronaldo Soares Ramos , Luciano de Oliveira Castro Lara , Thiago Galdino Balista , Julio Tomás Aquije Chacaltana
The Direct Interpolation Boundary Element Method (DIBEM) has proven to be a versatile, precise, and robust tool for transforming domain integrals into boundary integrals in the most diverse applications of the scalar field equation, such as the cases governed by the Equation of Stationary Poisson, Helmholtz, and Diffusion-Advection. DIBEM achieves this objective using radial basis functions to approximate the whole kernel of domain integrals composed of non-self-adjoint operators, frequently occurring in the mathematical modeling of complex problems. Using a simplified fundamental solution also allows for a more immediate and faster numerical solution without significantly losing precision in the results. In this work, DIBEM is used to solve transient heat transmission problems, which are governed by time-dependent partial differential equations and consist of one of the most important mathematical models for application in engineering, describing heat dissipation and absorption in equipment, machines, buildings, and metallurgical industrial processes, among others. Numerical tests evaluate the DIBEM model in two dimensions, in which different thermal loading variations over time, severe initial conditions, and accentuated variations in the diffusivity value are tested, aiming to assess the stability and consistency of the method.
直接插值边界元法(DIBEM)已被证明是一种通用的、精确的、健壮的工具,可以在标量场方程的最多样化应用中将域积分转换为边界积分,例如由平稳泊松方程、亥姆霍兹方程和扩散平流方程控制的情况。DIBEM利用径向基函数逼近由非自伴随算子组成的域积分的整个核,实现了这一目标,这在复杂问题的数学建模中经常出现。使用简化的基本解也允许更直接和更快的数值解,而不会显着失去结果的精度。在这项工作中,DIBEM用于解决瞬态传热问题,该问题由时变偏微分方程控制,并由工程应用中最重要的数学模型之一组成,描述设备,机器,建筑物和冶金工业过程中的散热和吸收,以及其他。数值试验在两个维度上对DIBEM模型进行了评估,分别测试了不同的热载荷随时间的变化、严酷的初始条件和扩散系数值的显著变化,以评估该方法的稳定性和一致性。
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引用次数: 0
The general finite difference method with the Krylov deferred correction technique for dynamic 2D and 3D piezoelectric analysis 采用Krylov延迟校正技术的一般有限差分法进行动态二维和三维压电分析
IF 2.5 2区 数学 Q1 MATHEMATICS, APPLIED Pub Date : 2025-10-27 DOI: 10.1016/j.camwa.2025.10.016
Xiangran Zheng , Qiang Wang , Wenxiang Sun , Yan Gu , Wenzhen Qu
This study presents a numerical framework with arbitrary-order accuracy for dynamic electroelastic analysis of two-dimensional (2D) and three-dimensional (3D) piezoelectric structures. The methodology achieves arbitrary-order convergence through a unified spatiotemporal coupling strategy. Temporal discretization is handled via the Krylov deferred correction (KDC) technique, which ensures asymptotically exact integration in time. For spatial approximation, the generalized finite difference method (GFDM) is employed, utilizing adaptive Taylor series expansions with matched orders to maintain consistency with temporal accuracy. An enhanced scheme is introduced for the enforcement of coupled electromechanical boundary conditions, improving numerical stability in cases where these conditions are not prescribed as explicit functions of time. To investigate the performance and reliability of the KDC-GFDM, four representative numerical examples are considered, covering both 2D and 3D cases with various geometric features and initial/boundary conditions. Numerically calculated results get systematically evaluated in comparison with available analytical solutions, when accessible, and with high-resolution reference solutions obtained from COMSOL Multiphysics.
本研究提出了一个具有任意阶精度的二维和三维压电结构动态电弹性分析的数值框架。该方法通过统一的时空耦合策略实现任意阶收敛。通过Krylov延迟校正(KDC)技术处理时间离散化,确保时间上的渐进精确积分。对于空间逼近,采用广义有限差分法(GFDM),利用匹配阶数的自适应泰勒级数展开保持与时间精度的一致性。引入了一种增强的方案来执行耦合机电边界条件,在这些条件不是作为时间的显式函数规定的情况下提高了数值稳定性。为了研究KDC-GFDM的性能和可靠性,考虑了四个具有代表性的数值算例,涵盖了具有不同几何特征和初始/边界条件的二维和三维情况。数值计算结果将与可用的解析解进行系统评估,并与COMSOL Multiphysics获得的高分辨率参考解进行比较。
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引用次数: 0
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Computers & Mathematics with Applications
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