Mathematical Models and Methods in Applied Sciences最新文献_第7页

Analysis of a fully-discrete, non-conforming approximation of evolution equations and applications 演化方程的全离散非一致性近似分析及其应用

Mathematical Models and Methods in Applied Sciences Pub Date : 2023-05-17 DOI: 10.1142/s0218202523500197

A. Kaltenbach, M. Ruzicka

{"title":"Analysis of a fully-discrete, non-conforming approximation of evolution equations and applications","authors":"A. Kaltenbach, M. Ruzicka","doi":"10.1142/s0218202523500197","DOIUrl":"https://doi.org/10.1142/s0218202523500197","url":null,"abstract":"In this paper, we consider a fully-discrete approximation of an abstract evolution equation deploying a non-conforming spatial approximation and finite differences in time (Rothe–Galerkin method). The main result is the convergence of the discrete solutions to a weak solution of the continuous problem. Therefore, the result can be interpreted either as a justification of the numerical method or as an alternative way of constructing weak solutions. We formulate the problem in the very general and abstract setting of so-called non-conforming Bochner pseudo-monotone operators, which allows for a unified treatment of several evolution problems. Our abstract results for non-conforming Bochner pseudo-monotone operators allow to establish (weak) convergence just by verifying a few natural assumptions on the operators time-by-time and on the discretization spaces. Hence, applications and extensions to several other evolution problems can be performed easily. We exemplify the applicability of our approach on several DG schemes for the unsteady [Formula: see text]-Navier–Stokes problem. The results of some numerical experiments are reported in the final section.","PeriodicalId":18311,"journal":{"name":"Mathematical Models and Methods in Applied Sciences","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135813114","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

A nonlinear bending theory for nematic LCE plates 向列LCE板的非线性弯曲理论

Mathematical Models and Methods in Applied Sciences Pub Date : 2023-05-04 DOI: 10.1142/s0218202523500331

Soren Bartels, Max Griehl, Stefan Neukamm, David Padilla-Garza, Christian Palus

{"title":"A nonlinear bending theory for nematic LCE plates","authors":"Soren Bartels, Max Griehl, Stefan Neukamm, David Padilla-Garza, Christian Palus","doi":"10.1142/s0218202523500331","DOIUrl":"https://doi.org/10.1142/s0218202523500331","url":null,"abstract":"In this paper, we study an elastic bilayer plate composed of a nematic liquid crystal elastomer in the top layer and a nonlinearly elastic material in the bottom layer. While the bottom layer is assumed to be stress-free in the flat reference configuration, the top layer features an eigenstrain that depends on the local liquid crystal orientation. As a consequence, the plate shows non-flat deformations in equilibrium with a geometry that non-trivially depends on the relative thickness and shape of the plate, material parameters, boundary conditions for the deformation, and anchorings of the liquid crystal orientation. We focus on thin plates in the bending regime and derive a two-dimensional bending model that combines a nonlinear bending energy for the deformation, with a surface Oseen–Frank energy for the director field that describes the local orientation of the liquid crystal elastomer. Both energies are nonlinearly coupled by means of a spontaneous curvature term that effectively describes the nematic-elastic coupling. We rigorously derive this model as a [Formula: see text]-limit from three-dimensional, nonlinear elasticity. We also devise a new numerical algorithm to compute stationary points of the two-dimensional model. We conduct numerical experiments and present simulation results that illustrate the practical properties of the proposed scheme as well as the rich mechanical behavior of the system.","PeriodicalId":18311,"journal":{"name":"Mathematical Models and Methods in Applied Sciences","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136265186","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Multilevel domain uncertainty quantification in computational electromagnetics 计算电磁学中的多水平域不确定性量化

Mathematical Models and Methods in Applied Sciences Pub Date : 2023-03-30 DOI: 10.1142/s0218202523500264

Ruben Aylwin, Carlos Jerez-Hanckes, Christoph Schwab, Jakob Zech

{"title":"Multilevel domain uncertainty quantification in computational electromagnetics","authors":"Ruben Aylwin, Carlos Jerez-Hanckes, Christoph Schwab, Jakob Zech","doi":"10.1142/s0218202523500264","DOIUrl":"https://doi.org/10.1142/s0218202523500264","url":null,"abstract":"We continue our study [R. Aylwin, C. Jerez-Hanckes, C. Schwab and J. Zech, Domain uncertainty quantification in computational electromagnetics, SIAM/ASA J. Uncertain. Quant. 8 (2020) 301–341] of the numerical approximation of time-harmonic electromagnetic fields for the Maxwell lossy cavity problem for uncertain geometries. We adopt the same affine-parametric shape parametrization framework, mapping the physical domains to a nominal polygonal domain with piecewise smooth maps. The regularity of the pullback solutions on the nominal domain is characterized in piecewise Sobolev spaces. We prove error convergence rates and optimize the algorithmic steering of parameters for edge-element discretizations in the nominal domain combined with: (a) multilevel Monte Carlo sampling, and (b) multilevel, sparse-grid quadrature for computing the expectation of the solutions with respect to uncertain domain ensembles. In addition, we analyze sparse-grid interpolation to compute surrogates of the domain-to-solution mappings. All calculations are performed on the polyhedral nominal domain, which enables the use of standard simplicial finite element meshes. We provide a rigorous fully discrete error analysis and show, in all cases, that dimension-independent algebraic convergence is achieved. For the multilevel sparse-grid quadrature methods, we prove higher order convergence rates free from the so-called curse of dimensionality. Numerical experiments confirm our theoretical results and verify the superiority of the sparse-grid methods.","PeriodicalId":18311,"journal":{"name":"Mathematical Models and Methods in Applied Sciences","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136002434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Bound-preserving finite element approximations of the Keller–Segel equations Keller-Segel方程的保界有限元逼近

Mathematical Models and Methods in Applied Sciences Pub Date : 2023-03-01 DOI: 10.1142/s0218202523500148

Santiago Badia, Jesus Bonilla, Juan Vicente Gutierrez-Santacreu

{"title":"Bound-preserving finite element approximations of the Keller–Segel equations","authors":"Santiago Badia, Jesus Bonilla, Juan Vicente Gutierrez-Santacreu","doi":"10.1142/s0218202523500148","DOIUrl":"https://doi.org/10.1142/s0218202523500148","url":null,"abstract":"This paper aims to develop numerical approximations of the Keller–Segel equations that mimic at the discrete level the lower bounds and the energy law of the continuous problem. We solve these equations for two unknowns: the organism (or cell) density, which is a positive variable, and the chemoattractant density, which is a non-negative variable. We propose two algorithms, which combine a stabilized finite element method and a semi-implicit time integration. The stabilization consists of a nonlinear artificial diffusion that employs a graph-Laplacian operator and a shock detector that localizes local extrema. As a result, both algorithms turn out to be nonlinear and can generate cell and chemoattractant numerical densities fulfilling lower bounds. However, the first algorithm requires a suitable constraint between the space and time discrete parameters, whereas the second one does not. We design the latter to attain a discrete energy law on acute meshes. We report some numerical experiments to validate the theoretical results on blowup and nonblowup phenomena. In the blowup setting, we identify a locking phenomenon that relates the [Formula: see text]-norm to the [Formula: see text]-norm limiting the growth of the singularity when supported on a macroelement.","PeriodicalId":18311,"journal":{"name":"Mathematical Models and Methods in Applied Sciences","volume":"116 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135796885","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Non-mean-field Vicsek-type models for collective behavior 集体行为的非平均场vicsek型模型

Mathematical Models and Methods in Applied Sciences Pub Date : 2023-02-02 DOI: 10.1142/s0218202522500646

Paolo Buttà, Ben Goddard, Thomas M. Hodgson, Michela Ottobre, Kevin J. Painter

{"title":"Non-mean-field Vicsek-type models for collective behavior","authors":"Paolo Buttà, Ben Goddard, Thomas M. Hodgson, Michela Ottobre, Kevin J. Painter","doi":"10.1142/s0218202522500646","DOIUrl":"https://doi.org/10.1142/s0218202522500646","url":null,"abstract":"We consider interacting particle dynamics with Vicsek-type interactions, and their macroscopic Partial Differential Equation (PDE) limit, in the non-mean-field regime; that is, we consider the case in which each particle/agent in the system interacts only with a prescribed subset of the particles in the system (for example, those within a certain distance). In this non-mean-field regime the influence between agents (i.e. the interaction term) can be normalized either by the total number of agents in the system (global scaling) or by the number of agents with which the particle is effectively interacting (local scaling). We compare the behavior of the globally scaled and the locally scaled systems in many respects, considering for each scaling both the PDE and the corresponding particle model. In particular, we observe that both the locally and globally scaled particle system exhibit pattern formation (i.e. formation of traveling-wave-like solutions) within certain parameter regimes, and generally display similar dynamics. The same is not true of the corresponding PDE models. Indeed, while both PDE models have multiple stationary states, for the globally scaled PDE such (space-homogeneous) equilibria are unstable for certain parameter regimes, with the instability leading to traveling wave solutions, while they are always stable for the locally scaled one, which never produces traveling waves. This observation is based on a careful numerical study of the model, supported by further analysis.","PeriodicalId":18311,"journal":{"name":"Mathematical Models and Methods in Applied Sciences","volume":"207 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138504563","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A diffuse-domain-based numerical method for a chemotaxis-fluid model 基于扩散域的趋化流体模型数值计算方法

Mathematical Models and Methods in Applied Sciences Pub Date : 2023-02-01 DOI: 10.1142/s0218202523500094

Chenxi Wang, Alina Chertock, Shumo Cui, Alexander Kurganov, Zhen Zhang

{"title":"A diffuse-domain-based numerical method for a chemotaxis-fluid model","authors":"Chenxi Wang, Alina Chertock, Shumo Cui, Alexander Kurganov, Zhen Zhang","doi":"10.1142/s0218202523500094","DOIUrl":"https://doi.org/10.1142/s0218202523500094","url":null,"abstract":"In this paper, we consider a coupled chemotaxis-fluid system that models self-organized collective behavior of oxytactic bacteria in a sessile drop. This model describes the biological chemotaxis phenomenon in the fluid environment and couples a convective chemotaxis system for the oxygen-consuming and oxytactic bacteria with the incompressible Navier–Stokes equations subject to a gravitational force, which is proportional to the relative surplus of the cell density compared to the water density. We develop a new positivity preserving and high-resolution method for the studied chemotaxis-fluid system. Our method is based on the diffuse-domain approach, which we use to derive a new chemotaxis-fluid diffuse-domain (cf-DD) model for simulating bioconvection in complex geometries. The drop domain is imbedded into a larger rectangular domain, and the original boundary is replaced by a diffuse interface with finite thickness. The original chemotaxis-fluid system is reformulated on the larger domain with additional source terms that approximate the boundary conditions on the physical interface. We show that the cf-DD model converges to the chemotaxis-fluid model asymptotically as the width of the diffuse interface shrinks to zero. We numerically solve the resulting cf-DD system by a second-order hybrid finite-volume finite-difference method and demonstrate the performance of the proposed approach on a number of numerical experiments that showcase several interesting chemotactic phenomena in sessile drops of different shapes, where the bacterial patterns depend on the droplet geometries.","PeriodicalId":18311,"journal":{"name":"Mathematical Models and Methods in Applied Sciences","volume":"71 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136153433","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

On the convergence of residual distribution schemes for the compressible Euler equations via dissipative weak solutions 利用耗散弱解研究可压缩欧拉方程剩余分布格式的收敛性

Mathematical Models and Methods in Applied Sciences Pub Date : 2023-01-01 DOI: 10.1142/s0218202523500057

Remi Abgrall, Maria Lukacova-Medvid'ova, Philipp Offner

引用次数: 3

Responding to Open Access: How German Museums use Digital Content 回应开放获取:德国博物馆如何使用数字内容

Mathematical Models and Methods in Applied Sciences Pub Date : 2019-07-18 DOI: 10.29311/MAS.V17I2.2756

Julia Wiedemann, Susanne B. Schmitt, E. Patzschke

引用次数: 3