Journal of Computational Physics最新文献_第8页

An energy stable high-order cut cell discontinuous Galerkin method with state redistribution for wave propagation 波传播的能量稳定高阶切割单元非连续伽勒金方法与状态再分布

IF 3.8 2区物理与天体物理

Journal of Computational Physics Pub Date : 2024-10-28 DOI: 10.1016/j.jcp.2024.113528

Christina G. Taylor , Lucas C. Wilcox , Jesse Chan

{"title":"An energy stable high-order cut cell discontinuous Galerkin method with state redistribution for wave propagation","authors":"Christina G. Taylor , Lucas C. Wilcox , Jesse Chan","doi":"10.1016/j.jcp.2024.113528","DOIUrl":"10.1016/j.jcp.2024.113528","url":null,"abstract":"<div><div>Cut meshes are a type of mesh that is formed by allowing embedded boundaries to “cut” a simple underlying mesh resulting in a hybrid mesh of cut and standard elements. While cut meshes can allow complex boundaries to be represented well regardless of the mesh resolution, their arbitrarily shaped and sized cut elements can present issues such as the <em>small cell problem</em>, where small cut elements can result in a severely restricted CFL condition. State redistribution, a technique developed by Berger and Giuliani in <span><span>[1]</span></span>, can be used to address the small cell problem. In this work, we pair state redistribution with a high-order discontinuous Galerkin scheme that is <span><math><msub><mrow><mi>L</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> energy stable under arbitrary quadrature. We prove that state redistribution can be added to a provably <span><math><msub><mrow><mi>L</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> energy stable discontinuous Galerkin method on a cut mesh without damaging the scheme's <span><math><msub><mrow><mi>L</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> stability. We numerically verify the high order accuracy and stability of our scheme on two-dimensional wave propagation problems.</div></div>","PeriodicalId":352,"journal":{"name":"Journal of Computational Physics","volume":"521 ","pages":"Article 113528"},"PeriodicalIF":3.8,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142554355","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 generalized framework of neural networks for Hamiltonian systems 哈密顿系统神经网络的广义框架

IF 3.8 2区物理与天体物理

Journal of Computational Physics Pub Date : 2024-10-28 DOI: 10.1016/j.jcp.2024.113536

Philipp Horn , Veronica Saz Ulibarrena , Barry Koren , Simon Portegies Zwart

{"title":"A generalized framework of neural networks for Hamiltonian systems","authors":"Philipp Horn , Veronica Saz Ulibarrena , Barry Koren , Simon Portegies Zwart","doi":"10.1016/j.jcp.2024.113536","DOIUrl":"10.1016/j.jcp.2024.113536","url":null,"abstract":"<div><div>When solving Hamiltonian systems using numerical integrators, preserving the symplectic structure may be crucial for many problems. At the same time, solving chaotic or stiff problems requires integrators to approximate the trajectories with extreme precision. So, integrating Hamilton's equations to a level of scientific reliability such that the answer can be used for scientific interpretation, may be computationally expensive. However, a neural network can be a viable alternative to numerical integrators, offering high-fidelity solutions orders of magnitudes faster.</div><div>To understand whether it is also important to preserve the symplecticity when neural networks are used, we analyze three well-known neural network architectures that are including the symplectic structure inside the neural network's topology. Between these neural network architectures many similarities can be found. This allows us to formulate a new, generalized framework for these architectures. In the generalized framework Symplectic Recurrent Neural Networks, SympNets and HénonNets are included as special cases. Additionally, this new framework enables us to find novel neural network topologies by transitioning between the established ones.</div><div>We compare new Generalized Hamiltonian Neural Networks (GHNNs) against the already established SympNets, HénonNets and physics-unaware multilayer perceptrons. This comparison is performed with data for a pendulum, a double pendulum and a gravitational 3-body problem. In order to achieve a fair comparison, the hyperparameters of the different neural networks are chosen such that the prediction speeds of all four architectures are the same during inference. A special focus lies on the capability of the neural networks to generalize outside the training data. The GHNNs outperform all other neural network architectures for the problems considered.</div></div>","PeriodicalId":352,"journal":{"name":"Journal of Computational Physics","volume":"521 ","pages":"Article 113536"},"PeriodicalIF":3.8,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142578701","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

Mass conservative limiting and applications to the approximation of the steady-state radiation transport equations 稳态辐射输运方程的质量保守极限和近似应用

IF 3.8 2区物理与天体物理

Journal of Computational Physics Pub Date : 2024-10-28 DOI: 10.1016/j.jcp.2024.113531

Jean-Luc Guermond , Zuodong Wang

引用次数: 0

An enhanced spectral boundary integral method for modeling highly nonlinear water waves in variable depth 用于模拟变深高度非线性水波的增强型光谱边界积分法

IF 3.8 2区物理与天体物理

Journal of Computational Physics Pub Date : 2024-10-28 DOI: 10.1016/j.jcp.2024.113525

Jinghua Wang

{"title":"An enhanced spectral boundary integral method for modeling highly nonlinear water waves in variable depth","authors":"Jinghua Wang","doi":"10.1016/j.jcp.2024.113525","DOIUrl":"10.1016/j.jcp.2024.113525","url":null,"abstract":"<div><div>This paper presents a new numerical model based on the highly nonlinear potential flow theory for simulating the propagation of water waves in variable depth. A new set of equations for estimating the surface vertical velocity is derived based on the boundary integral equation considering the water depth variability. A successive approximation scheme is also proposed in this study for calculating the surface vertical velocity. With the usage of Fast Fourier Transform, the model can be efficiently used for simulating highly nonlinear water waves on large spatiotemporal scale in a phase-resolving approach. The new model is comprehensively verified and validated through simulating a variety of nonlinear wave phenomenon including free propagating solitary wave, wave transformations over submerged bar, Bragg reflection over undulating bars, nonlinear evolution of Peregrine breather, obliquely propagating uniform waves and extreme waves in crossing random seas. Good agreements are achieved between the numerical simulations and laboratory measurements, indicating that the new model is sufficiently accurate. A discussion is presented on the accuracy and efficiency of the present model, which is compared with the Higher-Order Spectral method. The results show that the present model can be significantly more efficient at the same level of accuracy. It is suggested that the new model developed in the paper can be reliably used to simulate the nonlinear evolution of ocean waves in phase-resolving approach to shed light on the dynamics of nonlinear wave phenomenon taking place on a large spatiotemporal scale, which may be computationally expensive by using other existing methods.</div></div>","PeriodicalId":352,"journal":{"name":"Journal of Computational Physics","volume":"521 ","pages":"Article 113525"},"PeriodicalIF":3.8,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142560644","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

Comparison of rigorous scattering models to accurately replicate the behaviour of scattered electromagnetic waves in optical surface metrology 比较严格的散射模型，以准确复制光学表面计量中的散射电磁波行为

IF 3.8 2区物理与天体物理

Journal of Computational Physics Pub Date : 2024-10-26 DOI: 10.1016/j.jcp.2024.113519

Helia Hooshmand , Tobias Pahl , Poul-Erik Hansen , Liwei Fu , Alexander Birk , Mirza Karamehmedović , Peter Lehmann , Stephan Reichelt , Richard Leach , Samanta Piano

{"title":"Comparison of rigorous scattering models to accurately replicate the behaviour of scattered electromagnetic waves in optical surface metrology","authors":"Helia Hooshmand , Tobias Pahl , Poul-Erik Hansen , Liwei Fu , Alexander Birk , Mirza Karamehmedović , Peter Lehmann , Stephan Reichelt , Richard Leach , Samanta Piano","doi":"10.1016/j.jcp.2024.113519","DOIUrl":"10.1016/j.jcp.2024.113519","url":null,"abstract":"<div><div>Rigorous scattering models are based on Maxwell's equations and can provide high-accuracy solutions to model electromagnetic wave scattering from objects. Being able to calculate the scattered field from any surface geometry and considering the effect of the polarisation of the incident light, make rigorous models the most promising tools for complex light-matter interaction problems. The total intensity of the electric near-field scattering from a silicon cylinder illuminated by the transverse electric and transverse magnetic polarisation of the incident light is obtained using various rigorous models including, the local field Fourier modal method, boundary element method and finite element method. The intensity of the total electric near-field obtained by these rigorous models is compared using the Mie solution as a reference for both polarisation modes of the incident light. Additionally, the intensity of the total electric near-field scattered from a silicon sinusoid profile using the same rigorous models is analysed. The results are discussed in detail, and for the cylinder, the deviations in the intensity of the total electric field from the exact Mie solution are investigated.</div></div>","PeriodicalId":352,"journal":{"name":"Journal of Computational Physics","volume":"521 ","pages":"Article 113519"},"PeriodicalIF":3.8,"publicationDate":"2024-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142587080","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

Corrigendum to “Trace preserving quantum dynamics using a novel reparametrization-neutral summation-by-parts difference operator” [J.Comput.Phys. 425 (2021) 109917] 使用新型重参数化中性逐部求和差分算子的痕量保全量子动力学"[J.Comput.Phys. 425 (2021) 109917] 更正

IF 3.8 2区物理与天体物理

Journal of Computational Physics Pub Date : 2024-10-26 DOI: 10.1016/j.jcp.2024.113517

Oskar Ålund , Yukinao Akamatsu , Fredrik Laurén , Takahiro Miura , Jan Nordström , Alexander Rothkopf

引用次数: 0

Second order conservative Lagrangian DG schemes for compressible flow and their application in preserving spherical symmetry in two-dimensional cylindrical geometry 可压缩流动的二阶保守拉格朗日 DG 方案及其在二维圆柱几何中保持球面对称性的应用

IF 3.8 2区物理与天体物理

Journal of Computational Physics Pub Date : 2024-10-24 DOI: 10.1016/j.jcp.2024.113530

Wenjing Feng , Juan Cheng , Chi-Wang Shu

{"title":"Second order conservative Lagrangian DG schemes for compressible flow and their application in preserving spherical symmetry in two-dimensional cylindrical geometry","authors":"Wenjing Feng , Juan Cheng , Chi-Wang Shu","doi":"10.1016/j.jcp.2024.113530","DOIUrl":"10.1016/j.jcp.2024.113530","url":null,"abstract":"<div><div>In this paper, we construct a class of second-order cell-centered Lagrangian discontinuous Galerkin (DG) schemes for the two-dimensional compressible Euler equations on quadrilateral meshes. This Lagrangian DG scheme is based on the physical coordinates rather than the fixed reference coordinates, hence it does not require studying the evolution of the Jacobian matrix for the flow mapping between the different coordinates. The conserved variables are solved directly, and the scheme can preserve the conservation property for mass, momentum and total energy. The strong stability preserving (SSP) Runge-Kutta (RK) method is used for the time discretization. Furthermore, there are two main contributions. Firstly, differently from the previous work, we design a new Lagrangian DG scheme which is truly second-order accurate for all the variables such as density, momentum, total energy, pressure and velocity, while the similar DG schemes in the literature may lose second-order accuracy for certain variables, as shown in numerical experiments. Secondly, as an extension and application, we develop a particular Lagrangian DG scheme in the cylindrical geometry, which is designed to be able to preserve one-dimensional spherical symmetry for all the linear polynomials in two-dimensional cylindrical coordinates when computed on an equal-angle-zoned initial grid. The distinguished feature is that it can maintain both the spherical symmetry and conservation properties, which is very important for many applications such as implosion problems. A series of numerical experiments in the two-dimensional Cartesian and cylindrical coordinates are given to demonstrate the good performance of the Lagrangian DG schemes in terms of accuracy, symmetry and non-oscillation.</div></div>","PeriodicalId":352,"journal":{"name":"Journal of Computational Physics","volume":"521 ","pages":"Article 113530"},"PeriodicalIF":3.8,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142560650","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

Simplified inverse distance weighting-immersed boundary method for simulation of fluid-structure interaction 用于模拟流固耦合的简化反距离加权浸润边界法

IF 3.8 2区物理与天体物理

Journal of Computational Physics Pub Date : 2024-10-23 DOI: 10.1016/j.jcp.2024.113524

Buchen Wu , Yinjie Du , Chang Shu

{"title":"Simplified inverse distance weighting-immersed boundary method for simulation of fluid-structure interaction","authors":"Buchen Wu , Yinjie Du , Chang Shu","doi":"10.1016/j.jcp.2024.113524","DOIUrl":"10.1016/j.jcp.2024.113524","url":null,"abstract":"<div><div>When simulating fluid-structure interaction (FSI) problems involving moving objects, the implicit inverse distance weighting-immersed boundary method (IDW-IBM) developed by Du et al. <span><span>[1]</span></span> has to construct a large square correlation matrix and solve its inversion at each time step. In this work, a simplified inverse distance weighting-immersed boundary method (SIDW-IBM) is proposed to eliminate the intrinsic limitations in the original implicit IDW-IBM. Through error analysis using Taylor series expansion, a second order approximation can be derived, which allows us to approximate the large square correlation matrix into a diagonal matrix; thereby, we proposed the SIDW-IBM based on this second order approximation to explicitly evaluate the velocity corrections, where the needs to assemble the large correlation matrix and inverse it are circumvented. Owing to the fact that the inverse distance weighting interpolation removes the limitations in the Dirac delta function, the proposed SIDW-IBM has been successfully implemented on the non-uniform meshes to further improve the computational efficiency. The proposed SIDW-IBM is integrated with the reconstructed lattice Boltzmann flux solver (RLBFS) <span><span>[2]</span></span> to simulate some classic incompressible viscous flows, including flow past an in-line oscillating cylinder, flow past a heaving airfoil, and flow past a three-dimensional flexible plate. The good agreement between the present results and reference data demonstrates the capability and feasibility of the SIDW-IBM for simulating FSI problems with moving boundaries and large deformations.</div></div>","PeriodicalId":352,"journal":{"name":"Journal of Computational Physics","volume":"521 ","pages":"Article 113524"},"PeriodicalIF":3.8,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142553768","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 use of fast projection methods with unsteady velocity boundary conditions 关于使用非稳态速度边界条件的快速投影方法

IF 3.8 2区物理与天体物理

Journal of Computational Physics Pub Date : 2024-10-23 DOI: 10.1016/j.jcp.2024.113529

Maher Eid , Mokbel Karam , Tony Saad

{"title":"On the use of fast projection methods with unsteady velocity boundary conditions","authors":"Maher Eid , Mokbel Karam , Tony Saad","doi":"10.1016/j.jcp.2024.113529","DOIUrl":"10.1016/j.jcp.2024.113529","url":null,"abstract":"<div><div>This article aims at clarifying and amending a previously published result on the use of pseudo-pressure approximations for fast incompressible Navier-Stokes solvers with time-dependent boundary conditions. Fast projection methods were proposed to speed up high-order incompressible Navier-Stokes solvers by replacing pressure projections with simple approximations. A generalized approximation theory was proposed in <span><span>[1]</span></span>, in which the time-dependent boundary conditions were ignored. In this comment, we investigate the effect of unsteady boundary conditions on the order of accuracy and demonstrate that the pressure approximations derived in <span><span>[1]</span></span> hold for all RK2 integrators, while RK3 approximations are only third order for certain sets of coefficients. We show that third order is lost for other cases and shed light on why order is broken. This work serves as a reference for the treatment of unsteady boundary conditions for fast-projection methods. Numerical validation is performed on a well established channel flow problem with a variety of unsteady inlet conditions for a wide range of explicit RK2 and RK3 integrators.</div></div>","PeriodicalId":352,"journal":{"name":"Journal of Computational Physics","volume":"521 ","pages":"Article 113529"},"PeriodicalIF":3.8,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142554229","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

Polytopic autoencoders with smooth clustering for reduced-order modeling of flows 具有平滑聚类功能的多拓扑自编码器，用于简化流量建模

IF 3.8 2区物理与天体物理

Journal of Computational Physics Pub Date : 2024-10-23 DOI: 10.1016/j.jcp.2024.113526

Jan Heiland , Yongho Kim

引用次数: 0