Pub Date : 2026-04-01Epub Date: 2025-12-31DOI: 10.1016/j.jcp.2025.114637
Antonio Ghidoni , Edoardo Mantecca , Gianmaria Noventa , David Pasquale
The aim of this paper is to describe, validate and assess an explicit wall function implementation for the high-order spatial discretization of the Reynolds-Averaged Navier-Stokes and turbulence model equations. Wall functions are used to increase the computational efficiency of the solvers for numerical simulations, reducing the need for high quality computational meshes with fine near-wall spatial resolution. An explicit power-law to model the velocity profile of the flow in the boundary layer allows the proposed formulation to avoid iterative computations and ensures enhanced computational efficiency and robustness. These are demonstrated on different test cases with turbulent flows and adiabatic wall modelled boundaries. The accuracy of the numerical solutions is preserved up to a non dimensional height of the first element adjacent to the wall of 320 with a drastic computing time reduction. The high-order spatial discretization and the proposed formulation of wall function pave the way for numerical simulation of complex industrial applications with very coarse near-wall spatial resolution.
{"title":"Assessment of an explicit wall function implementation for the high-order discontinuous Galerkin solution of the RANS and k−ω turbulence model equations","authors":"Antonio Ghidoni , Edoardo Mantecca , Gianmaria Noventa , David Pasquale","doi":"10.1016/j.jcp.2025.114637","DOIUrl":"10.1016/j.jcp.2025.114637","url":null,"abstract":"<div><div>The aim of this paper is to describe, validate and assess an explicit wall function implementation for the high-order spatial discretization of the Reynolds-Averaged Navier-Stokes and <span><math><mrow><mi>k</mi><mspace></mspace><mo>−</mo><mspace></mspace><mi>ω</mi></mrow></math></span> turbulence model equations. Wall functions are used to increase the computational efficiency of the solvers for numerical simulations, reducing the need for high quality computational meshes with fine near-wall spatial resolution. An explicit power-law to model the velocity profile of the flow in the boundary layer allows the proposed formulation to avoid iterative computations and ensures enhanced computational efficiency and robustness. These are demonstrated on different test cases with turbulent flows and adiabatic wall modelled boundaries. The accuracy of the numerical solutions is preserved up to a non dimensional height of the first element adjacent to the wall of 320 with a drastic computing time reduction. The high-order spatial discretization and the proposed formulation of wall function pave the way for numerical simulation of complex industrial applications with very coarse near-wall spatial resolution.</div></div>","PeriodicalId":352,"journal":{"name":"Journal of Computational Physics","volume":"550 ","pages":"Article 114637"},"PeriodicalIF":3.8,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145903986","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}
Updated Lagrangian smoothed particle hydrodynamics (SPH) for solid dynamics is often plagued by numerical instabilities, particularly hourglass modes that produce unphysical zigzag patterns. While recent essentially non-hourglass (SPH-ENOG) and generalized non-hourglass (SPH-GNOG) formulations have improved stability, they suffer from poor angular momentum conservation, limiting their accuracy in rotational problems. To overcome this, this paper presents two angular-momentum enhanced non-hourglass formulations. First, we enhance the SPH-ENOG method with rotation matrices derived from Rodrigues’ formula, creating SPH-ENOG-A for elastic materials, which explicitly accounts for rigid rotations during time integration, thereby significantly enhancing angular momentum conservation. To strictly enforce linear momentum conservation, the average of the rotation matrices is computed and applied to each particle. We then extend this approach to reformulate the corrective term in SPH-GNOG, yielding SPH-GNOG-A—a unified method for both elastic and plastic materials that not only improves angular momentum conservation but also eliminates prior dependencies on material-specific coefficients. Validated against elastic (oscillating plates, spinning solids) and plastic (Taylor bars, high-velocity impacts) benchmarks, our methods retain the hourglass-free stability, convergence, and accuracy of their predecessors while achieving a significant leap in angular momentum conservation.
用于固体动力学的更新拉格朗日光滑粒子流体动力学(SPH)经常受到数值不稳定性的困扰,特别是产生非物理之字形的沙漏模式。虽然最近的基本非沙漏(SPH-ENOG)和广义非沙漏(SPH-GNOG)配方提高了稳定性,但它们的角动量守恒性差,限制了它们在旋转问题中的精度。为了克服这个问题,本文提出了两种角动量增强的非沙漏公式。首先,我们利用Rodrigues公式导出的旋转矩阵对SPH-ENOG方法进行了改进,创建了弹性材料的SPH-ENOG- a,该方法在时间积分过程中明确考虑了刚性旋转,从而显著提高了角动量守恒。为了严格执行线性动量守恒,计算旋转矩阵的平均值并将其应用于每个粒子。然后,我们将该方法扩展到SPH-GNOG中重新制定校正项,从而得到SPH-GNOG- a -一种适用于弹性和塑性材料的统一方法,该方法不仅改善了角动量守恒,而且消除了对材料特定系数的先前依赖。经过弹性(振荡板,旋转固体)和塑料(泰勒杆,高速撞击)基准的验证,我们的方法保留了其前辈的无沙漏稳定性,收敛性和准确性,同时实现了角动量守恒的重大飞跃。
{"title":"Angular-momentum enhanced non-hourglass formulation for SPH solid dynamics","authors":"Shuaihao Zhang , Jidong Zhao , Honghu Zhu , Xiangyu Hu","doi":"10.1016/j.jcp.2025.114646","DOIUrl":"10.1016/j.jcp.2025.114646","url":null,"abstract":"<div><div>Updated Lagrangian smoothed particle hydrodynamics (SPH) for solid dynamics is often plagued by numerical instabilities, particularly hourglass modes that produce unphysical zigzag patterns. While recent essentially non-hourglass (SPH-ENOG) and generalized non-hourglass (SPH-GNOG) formulations have improved stability, they suffer from poor angular momentum conservation, limiting their accuracy in rotational problems. To overcome this, this paper presents two angular-momentum enhanced non-hourglass formulations. First, we enhance the SPH-ENOG method with rotation matrices derived from Rodrigues’ formula, creating SPH-ENOG-A for elastic materials, which explicitly accounts for rigid rotations during time integration, thereby significantly enhancing angular momentum conservation. To strictly enforce linear momentum conservation, the average of the rotation matrices is computed and applied to each particle. We then extend this approach to reformulate the corrective term in SPH-GNOG, yielding SPH-GNOG-A—a unified method for both elastic and plastic materials that not only improves angular momentum conservation but also eliminates prior dependencies on material-specific coefficients. Validated against elastic (oscillating plates, spinning solids) and plastic (Taylor bars, high-velocity impacts) benchmarks, our methods retain the hourglass-free stability, convergence, and accuracy of their predecessors while achieving a significant leap in angular momentum conservation.</div></div>","PeriodicalId":352,"journal":{"name":"Journal of Computational Physics","volume":"550 ","pages":"Article 114646"},"PeriodicalIF":3.8,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145903988","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}
Classical Finite Volume methods for multi-dimensional problems include stabilization (e.g. via a Riemann solver), that is derived by considering several one-dimensional problems in different directions. Such methods therefore ignore a possibly existing balance of contributions coming from different directions, such as the one characterizing multi-dimensional stationary states. Instead of being preserved, they are usually diffused away by such methods. Stationarity preserving methods use a better suited stabilization term that vanishes at the stationary state, allowing the method to preserve it. This work presents a general approach to stationarity preserving Finite Volume methods for nonlinear conservation/balance laws. It is based on a multi-dimensional stationarity preserving quadrature strategy that allows to naturally introduce genuinely multi-dimensional numerical fluxes. The new methods are shown to significantly outperform existing ones even if the latter are of higher order of accuracy and even on non-stationary solutions.
{"title":"Genuinely multi-dimensional stationarity preserving Finite Volume formulation for nonlinear hyperbolic PDEs","authors":"Wasilij Barsukow , Mirco Ciallella , Mario Ricchiuto , Davide Torlo","doi":"10.1016/j.jcp.2025.114633","DOIUrl":"10.1016/j.jcp.2025.114633","url":null,"abstract":"<div><div>Classical Finite Volume methods for multi-dimensional problems include stabilization (e.g. via a Riemann solver), that is derived by considering several one-dimensional problems in different directions. Such methods therefore ignore a possibly existing balance of contributions coming from different directions, such as the one characterizing multi-dimensional stationary states. Instead of being preserved, they are usually diffused away by such methods. Stationarity preserving methods use a better suited stabilization term that vanishes at the stationary state, allowing the method to preserve it. This work presents a general approach to stationarity preserving Finite Volume methods for nonlinear conservation/balance laws. It is based on a multi-dimensional stationarity preserving quadrature strategy that allows to naturally introduce genuinely multi-dimensional numerical fluxes. The new methods are shown to significantly outperform existing ones even if the latter are of higher order of accuracy and even on non-stationary solutions.</div></div>","PeriodicalId":352,"journal":{"name":"Journal of Computational Physics","volume":"550 ","pages":"Article 114633"},"PeriodicalIF":3.8,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145974703","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}
Pub Date : 2026-04-01Epub Date: 2025-12-31DOI: 10.1016/j.jcp.2025.114649
Jan Nordström
In previous work, we derived new energy and entropy stable open boundary conditions and implementation techniques for linear and nonlinear initial boundary value problems. These boundary procedures result in estimates bounded by external data only. Interestingly, these new boundary conditions generalize the well-known classical characteristic boundary conditions for linear problems to the nonlinear setting. We discuss the similarities and differences between these two boundary procedures and point out the advantages with the new procedures. In particular we show that the new boundary conditions bound solutions to both linear and nonlinear initial boundary value problems and can be implemented both strongly and weakly.
{"title":"Linear and nonlinear boundary conditions: What’s the difference?","authors":"Jan Nordström","doi":"10.1016/j.jcp.2025.114649","DOIUrl":"10.1016/j.jcp.2025.114649","url":null,"abstract":"<div><div>In previous work, we derived new energy and entropy stable open boundary conditions and implementation techniques for linear and nonlinear initial boundary value problems. These boundary procedures result in estimates bounded by external data only. Interestingly, these new boundary conditions generalize the well-known classical characteristic boundary conditions for linear problems to the nonlinear setting. We discuss the similarities and differences between these two boundary procedures and point out the advantages with the new procedures. In particular we show that the new boundary conditions bound solutions to both linear and nonlinear initial boundary value problems and can be implemented both strongly and weakly.</div></div>","PeriodicalId":352,"journal":{"name":"Journal of Computational Physics","volume":"550 ","pages":"Article 114649"},"PeriodicalIF":3.8,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145974764","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}
Pub Date : 2026-04-01Epub Date: 2026-01-06DOI: 10.1016/j.jcp.2025.114650
Tianrun Gao , Mingduo Yuan , Lin Fu
In this study, a general smoothed particle-mesh hydrodynamics (SPMH) method is developed for fluid-structure interaction (FSI), particularly for those involving thin structures. The proposed SPMH method obtains improved accuracy in the user-defined mesh domain, which is typically defined near the thin structures. Meanwhile, SPMH can also preserve the free-surface tracking ability of smoothed particle hydrodynamics (SPH). The SPMH integrates SPH and finite-volume method (FVM), for which the weakly compressible SPH and unstructured arbitrary Lagrangian-Eulerian (ALE) FVM are adopted, respectively. The mesh update of the ALE framework is achieved by combining the finite-element method (FEM) with the spring analogy method. For thin structures, a new beam solver degenerated from the three-dimensional shell is developed based on FVM. In SPMH, the data communication between particle and mesh domains is achieved through activated, non-activated particles of SPH particles and interface points on mesh domain edges. To handle the free-surface flow in the mesh domain, the fluid-phase and void cells are identified according to the non-activated SPH particles, and flux calculation at the free-surface region is designed accordingly. A set of challenging FSI cases involving thin structures is simulated using the proposed SPMH method, and SPMH shows higher accuracy than the previous SPH method, particularly for FSI problems in the specified mesh domain.
{"title":"Smoothed particle-mesh hydrodynamics (SPMH) for fluid-structure interactions involving thin structures","authors":"Tianrun Gao , Mingduo Yuan , Lin Fu","doi":"10.1016/j.jcp.2025.114650","DOIUrl":"10.1016/j.jcp.2025.114650","url":null,"abstract":"<div><div>In this study, a general smoothed particle-mesh hydrodynamics (SPMH) method is developed for fluid-structure interaction (FSI), particularly for those involving thin structures. The proposed SPMH method obtains improved accuracy in the user-defined mesh domain, which is typically defined near the thin structures. Meanwhile, SPMH can also preserve the free-surface tracking ability of smoothed particle hydrodynamics (SPH). The SPMH integrates SPH and finite-volume method (FVM), for which the weakly compressible SPH and unstructured arbitrary Lagrangian-Eulerian (ALE) FVM are adopted, respectively. The mesh update of the ALE framework is achieved by combining the finite-element method (FEM) with the spring analogy method. For thin structures, a new beam solver degenerated from the three-dimensional shell is developed based on FVM. In SPMH, the data communication between particle and mesh domains is achieved through activated, non-activated particles of SPH particles and interface points on mesh domain edges. To handle the free-surface flow in the mesh domain, the fluid-phase and void cells are identified according to the non-activated SPH particles, and flux calculation at the free-surface region is designed accordingly. A set of challenging FSI cases involving thin structures is simulated using the proposed SPMH method, and SPMH shows higher accuracy than the previous SPH method, particularly for FSI problems in the specified mesh domain.</div></div>","PeriodicalId":352,"journal":{"name":"Journal of Computational Physics","volume":"550 ","pages":"Article 114650"},"PeriodicalIF":3.8,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923627","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}
Pub Date : 2026-04-01Epub Date: 2025-12-31DOI: 10.1016/j.jcp.2025.114642
Bangti Jin, Fengru Wang, Jun Zou
We develop a novel iterative direct sampling method (IDSM) for solving linear or nonlinear elliptic inverse problems with partial Cauchy data. It integrates three innovations: a data completion scheme to reconstruct missing boundary information, a heterogeneously regularized Dirichlet-to-Neumann map to enhance the near-orthogonality of probing functions, and a stabilization-correction strategy to ensure the numerical stability. The resulting method is remarkably robust with respect to measurement noise, is flexible with the measurement configuration, enjoys provable stability guarantee, and achieves enhanced resolution for recovering inhomogeneities. Numerical experiments in electrical impedance tomography, diffuse optical tomography, and cardiac electrophysiology show its effectiveness in accurately reconstructing the locations and geometries of inhomogeneities.
{"title":"A stable iterative direct sampling method for elliptic inverse problems with partial Cauchy data","authors":"Bangti Jin, Fengru Wang, Jun Zou","doi":"10.1016/j.jcp.2025.114642","DOIUrl":"10.1016/j.jcp.2025.114642","url":null,"abstract":"<div><div>We develop a novel iterative direct sampling method (IDSM) for solving linear or nonlinear elliptic inverse problems with partial Cauchy data. It integrates three innovations: a data completion scheme to reconstruct missing boundary information, a heterogeneously regularized Dirichlet-to-Neumann map to enhance the near-orthogonality of probing functions, and a stabilization-correction strategy to ensure the numerical stability. The resulting method is remarkably robust with respect to measurement noise, is flexible with the measurement configuration, enjoys provable stability guarantee, and achieves enhanced resolution for recovering inhomogeneities. Numerical experiments in electrical impedance tomography, diffuse optical tomography, and cardiac electrophysiology show its effectiveness in accurately reconstructing the locations and geometries of inhomogeneities.</div></div>","PeriodicalId":352,"journal":{"name":"Journal of Computational Physics","volume":"550 ","pages":"Article 114642"},"PeriodicalIF":3.8,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923623","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}
Pub Date : 2026-04-01Epub Date: 2026-01-01DOI: 10.1016/j.jcp.2025.114648
Beibei Li
In this work we propose a unified Fourier Spectral Transformer network that integrates the strengths of classical spectral methods and attention based neural architectures. By transforming the original PDEs into spectral ordinary differential equations, we use high precision numerical solvers to generate training data and use a Transformer network to model the evolution of the spectral coefficients. We design two complementary sequence models for the evolution of spectral coefficients, a Fourier Spectral Transformer and an exponential time difference Transformer. The latter embeds the analytic linear propagator of the PDE through an exponential time differencing update, while a Transformer is used to learn the nonlinear contribution. We evaluate the proposed Transformer with Burgers’ equation, two-dimensional and three-dimensional incompressible Navier-Stokes equations. The numerical experiments show that the models achieve highly accurate long-term predictions from relatively limited training data, and that the exponential time difference Transformer exhibits improved stability and convergence. The proposed Transformer generalizes well to unseen data, bringing a promising paradigm for real time prediction and control of complex dynamical systems.
{"title":"The Fourier Spectral Transformer for efficient and generalizable nonlinear PDEs","authors":"Beibei Li","doi":"10.1016/j.jcp.2025.114648","DOIUrl":"10.1016/j.jcp.2025.114648","url":null,"abstract":"<div><div>In this work we propose a unified Fourier Spectral Transformer network that integrates the strengths of classical spectral methods and attention based neural architectures. By transforming the original PDEs into spectral ordinary differential equations, we use high precision numerical solvers to generate training data and use a Transformer network to model the evolution of the spectral coefficients. We design two complementary sequence models for the evolution of spectral coefficients, a Fourier Spectral Transformer and an exponential time difference Transformer. The latter embeds the analytic linear propagator of the PDE through an exponential time differencing update, while a Transformer is used to learn the nonlinear contribution. We evaluate the proposed Transformer with Burgers’ equation, two-dimensional and three-dimensional incompressible Navier-Stokes equations. The numerical experiments show that the models achieve highly accurate long-term predictions from relatively limited training data, and that the exponential time difference Transformer exhibits improved stability and convergence. The proposed Transformer generalizes well to unseen data, bringing a promising paradigm for real time prediction and control of complex dynamical systems.</div></div>","PeriodicalId":352,"journal":{"name":"Journal of Computational Physics","volume":"550 ","pages":"Article 114648"},"PeriodicalIF":3.8,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923629","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}
Pub Date : 2026-04-01Epub Date: 2026-01-07DOI: 10.1016/j.jcp.2026.114653
Bonan Xu , Chang Sun , Peixu Guo
The simulation of transcritical flows remains challenging due to strong thermodynamic nonlinearities that induce spurious pressure oscillations in conventional schemes.While primitive-variable formulations offer improved robustness under such conditions, they are always limited by energy conservation errors and the absence of systematic high-order treatments for numerical fluxes. In this paper, we introduce the Central Differential flux with High-Order Dissipation (CDHD), a novel numerical flux solver designed for primitive-variable discretization. This method combines a central flux for advection with a minimal, upwind-biased dissipation term to stabilize the simulation while maintaining formal accuracy. The dissipation term effectively suppresses oscillations and improves stability in transcritical flows. Compared to traditional primitive-variable approaches, CDHD reduces the energy conservation error in two order of magnitude. When incorporated into a hybrid framework with a conservative shock-capturing scheme, the method robustly handles both smooth transcritical phenomena and shock waves. Numerical tests validate the accuracy, stability, and energy-preserving capabilities of CDHD, demonstrating its potential as a reliable tool for complex real-gas flow simulations.
{"title":"A Central Differential flux with high-Order dissipation for robust simulations of transcritical flows","authors":"Bonan Xu , Chang Sun , Peixu Guo","doi":"10.1016/j.jcp.2026.114653","DOIUrl":"10.1016/j.jcp.2026.114653","url":null,"abstract":"<div><div>The simulation of transcritical flows remains challenging due to strong thermodynamic nonlinearities that induce spurious pressure oscillations in conventional schemes.While primitive-variable formulations offer improved robustness under such conditions, they are always limited by energy conservation errors and the absence of systematic high-order treatments for numerical fluxes. In this paper, we introduce the Central Differential flux with High-Order Dissipation (CDHD), a novel numerical flux solver designed for primitive-variable discretization. This method combines a central flux for advection with a minimal, upwind-biased dissipation term to stabilize the simulation while maintaining formal accuracy. The dissipation term effectively suppresses oscillations and improves stability in transcritical flows. Compared to traditional primitive-variable approaches, CDHD reduces the energy conservation error in two order of magnitude. When incorporated into a hybrid framework with a conservative shock-capturing scheme, the method robustly handles both smooth transcritical phenomena and shock waves. Numerical tests validate the accuracy, stability, and energy-preserving capabilities of CDHD, demonstrating its potential as a reliable tool for complex real-gas flow simulations.</div></div>","PeriodicalId":352,"journal":{"name":"Journal of Computational Physics","volume":"550 ","pages":"Article 114653"},"PeriodicalIF":3.8,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923625","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}
Pub Date : 2026-04-01Epub Date: 2026-01-09DOI: 10.1016/j.jcp.2026.114667
Yuan Yu , Siwei Chen , Yuting Zhou , Lei Wang , Hai-Zhuan Yuan , Shi Shu
The high Weissenberg number problem has been a persistent challenge in the numerical simulation of viscoelastic fluid flows. This paper presents an improved lattice Boltzmann method for solving viscoelastic flow problems at high Weissenberg numbers. The proposed approach employs two independent two-relaxation-time regularized lattice Boltzmann models to solve the hydrodynamic field and conformation tensor field of viscoelastic fluid flows, respectively. The viscoelastic stress computed from the conformation tensor is directly embedded into the hydrodynamic field using a newly proposed local velocity discretization scheme, thereby avoiding spatial gradient calculations. The constitutive equations are treated as convection-diffusion equations and solved using an improved convection-diffusion model specifically designed for this purpose, incorporating a novel auxiliary source term that eliminates the need for spatial and temporal derivative computations. Additionally, a conservative non-equilibrium bounce-back (CNEBB) scheme is proposed for implementing solid wall boundary conditions in the constitutive equations. The robustness of the present algorithm is validated through a series of benchmark problems. The simplified four-roll mill problem demonstrates that the method effectively improves numerical accuracy and stability in bulk regions containing stress singularities. The Poiseuille flow problem validates the accuracy of the current algorithm with the CNEBB boundary scheme at extremely high Weissenberg numbers (tested up to ). The flow past a circular cylinder problem confirms the superior stability and applicability of the scheme for complex curved boundary problems compared to other existing common schemes.
{"title":"An improved lattice Boltzmann method with a novel conservative boundary scheme for viscoelastic fluid flows","authors":"Yuan Yu , Siwei Chen , Yuting Zhou , Lei Wang , Hai-Zhuan Yuan , Shi Shu","doi":"10.1016/j.jcp.2026.114667","DOIUrl":"10.1016/j.jcp.2026.114667","url":null,"abstract":"<div><div>The high Weissenberg number problem has been a persistent challenge in the numerical simulation of viscoelastic fluid flows. This paper presents an improved lattice Boltzmann method for solving viscoelastic flow problems at high Weissenberg numbers. The proposed approach employs two independent two-relaxation-time regularized lattice Boltzmann models to solve the hydrodynamic field and conformation tensor field of viscoelastic fluid flows, respectively. The viscoelastic stress computed from the conformation tensor is directly embedded into the hydrodynamic field using a newly proposed local velocity discretization scheme, thereby avoiding spatial gradient calculations. The constitutive equations are treated as convection-diffusion equations and solved using an improved convection-diffusion model specifically designed for this purpose, incorporating a novel auxiliary source term that eliminates the need for spatial and temporal derivative computations. Additionally, a conservative non-equilibrium bounce-back (CNEBB) scheme is proposed for implementing solid wall boundary conditions in the constitutive equations. The robustness of the present algorithm is validated through a series of benchmark problems. The simplified four-roll mill problem demonstrates that the method effectively improves numerical accuracy and stability in bulk regions containing stress singularities. The Poiseuille flow problem validates the accuracy of the current algorithm with the CNEBB boundary scheme at extremely high Weissenberg numbers (tested up to <span><math><mrow><mtext>Wi</mtext><mo>=</mo><mn>10000</mn></mrow></math></span>). The flow past a circular cylinder problem confirms the superior stability and applicability of the scheme for complex curved boundary problems compared to other existing common schemes.</div></div>","PeriodicalId":352,"journal":{"name":"Journal of Computational Physics","volume":"550 ","pages":"Article 114667"},"PeriodicalIF":3.8,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145974765","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}
Pub Date : 2026-04-01Epub Date: 2026-01-05DOI: 10.1016/j.jcp.2026.114652
Lukas Exl , Sebastian Schaffer
We present an extension of the tensor grid method for stray field computation on rectangular domains that incorporates higher-order basis functions. Both the magnetization and the resulting magnetic field are represented using higher-order B-spline bases, which allow for increased accuracy and smoothness. The method employs a super-potential formulation, which circumvents the need to convolve with a singular kernel. The field is represented with high accuracy as a functional Tucker tensor, leveraging separable expansions on the tensor product domain and trained via a multilinear extension of the extreme learning machine methodology. Unlike conventional grid-based methods, the proposed mesh-free approach allows for continuous field evaluation. Numerical experiments confirm the accuracy and efficiency of the proposed method, demonstrating exponential convergence of the energy and linear computational scaling with respect to the multilinear expansion rank.
{"title":"Higher order stray field computation on tensor product domains","authors":"Lukas Exl , Sebastian Schaffer","doi":"10.1016/j.jcp.2026.114652","DOIUrl":"10.1016/j.jcp.2026.114652","url":null,"abstract":"<div><div>We present an extension of the tensor grid method for stray field computation on rectangular domains that incorporates higher-order basis functions. Both the magnetization and the resulting magnetic field are represented using higher-order B-spline bases, which allow for increased accuracy and smoothness. The method employs a super-potential formulation, which circumvents the need to convolve with a singular kernel. The field is represented with high accuracy as a functional Tucker tensor, leveraging separable expansions on the tensor product domain and trained via a multilinear extension of the extreme learning machine methodology. Unlike conventional grid-based methods, the proposed mesh-free approach allows for continuous field evaluation. Numerical experiments confirm the accuracy and efficiency of the proposed method, demonstrating exponential convergence of the energy and linear computational scaling with respect to the multilinear expansion rank.</div></div>","PeriodicalId":352,"journal":{"name":"Journal of Computational Physics","volume":"550 ","pages":"Article 114652"},"PeriodicalIF":3.8,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923624","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}