Computational Mathematics and Mathematical Physics最新文献_第10页

Stability Analysis of Polymerization Fronts 聚合前沿稳定性分析

IF 0.7 4区数学

Computational Mathematics and Mathematical Physics Pub Date : 2024-01-29 DOI: 10.1134/s0965542523120138

Y. Joundy, H. Rouah, A. Taik

引用次数: 0

Generalization of the Penalized Wall Function Method for Modeling of Turbulent Flows with Adverse Pressure Gradient 为模拟具有不利压力梯度的湍流而对惩罚性壁面函数法进行概括

IF 0.7 4区数学

Computational Mathematics and Mathematical Physics Pub Date : 2024-01-29 DOI: 10.1134/s0965542523120199

O. V. Vasilyev, N. S. Zhdanova

引用次数: 0

Projector Approach to the Butuzov–Nefedov Algorithm for Finding Asymptotic Solutions for a Class of Discrete Problems with a Small Step 布图佐夫-涅菲多夫算法的投影器方法，用于寻找一类小步离散问题的渐近解

IF 0.7 4区数学

Computational Mathematics and Mathematical Physics Pub Date : 2024-01-01 DOI: 10.1134/s096554252401010x

{"title":"Projector Approach to the Butuzov–Nefedov Algorithm for Finding Asymptotic Solutions for a Class of Discrete Problems with a Small Step","authors":"","doi":"10.1134/s096554252401010x","DOIUrl":"https://doi.org/10.1134/s096554252401010x","url":null,"abstract":" <h3>Abstract</h3> V.F. Butuzov and N.N. Nefedov proposed an algorithm for constructing asymptotics with boundary functions of two types for solving a discrete initial value problem with a small step ({{varepsilon }^{2}}) and a nonlinear term of order (varepsilon ) in the critical case, i.e., when the degenerate equation with (varepsilon = 0) is not solvable uniquely for the unknown variable. In this paper, an asymptotic solution of the same problem is constructed by applying a new approach based on orthogonal projectors onto (ker (B(t) - I)) and (ker (B(t) - I){kern 1pt} ') , where (B(t)) is the matrix premultiplying the unknown variable in the linear part of the equation, (I) is the identity matrix of suitable size, and the prime denotes transposition. This approach considerably simplifies the understanding of the asymptotics-constructing algorithm and makes it possible to represent the problems of finding asymptotic terms of any order in explicit form, which is convenient for researchers applying asymptotic methods for real-world problems. ","PeriodicalId":55230,"journal":{"name":"Computational Mathematics and Mathematical Physics","volume":"133 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140196212","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Sensitivity of the Functionals of the Variational Data Assimilation Problem when Reconstructing the Initial State and Heat Flux for a Model of Sea Thermodynamics 为海洋热力学模型重建初始状态和热通量时变量数据同化问题函数的敏感性

IF 0.7 4区数学

Computational Mathematics and Mathematical Physics Pub Date : 2024-01-01 DOI: 10.1134/s0965542524010135

引用次数: 0

Convergence of a Numerical Method for Solving the Optimal Control Problem of Panel Forming under Creep Conditions 解决蠕变条件下板材成型优化控制问题的数值方法的收敛性

IF 0.7 4区数学

Computational Mathematics and Mathematical Physics Pub Date : 2024-01-01 DOI: 10.1134/s0965542524010032

引用次数: 0

An Approach to the Implementation of the Multigrid Method with Full Approximation for CFD Problems 针对 CFD 问题实施全近似多网格法的方法

IF 0.7 4区数学

Computational Mathematics and Mathematical Physics Pub Date : 2023-12-25 DOI: 10.1134/s0965542523110106

A. V. Gorobets

{"title":"An Approach to the Implementation of the Multigrid Method with Full Approximation for CFD Problems","authors":"A. V. Gorobets","doi":"10.1134/s0965542523110106","DOIUrl":"https://doi.org/10.1134/s0965542523110106","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3>This paper is devoted to the use of the multigrid method to accelerate calculations of compressible flows in a stationary formulation on unstructured grids. The multigrid method is used with the construction of a full approximation for each grid level (FAS MG—Full Approximation Scheme Multigrid). In the case of an unstructured grid, such a method can cause difficulties associated both with the construction of grid levels and transition operators between them, and with software implementation in the existing simulation code. The program needs to deal with several different discretizations at once. If the entire data structure, including arrays with grid data, topology, and time integration data, was designed to work on a single grid, then the implementation of the FAS MG can turn into a disaster involving rewriting the entire code. The purpose of this work is to achieve multiple acceleration of calculations at the cost of minimal effort. The problem of implementing the multigrid method on the basis of an existing software package that was not designed to work with several grid levels is solved. The implementation of the multigrid method in an MPI parallel code is carried out in such a way that there is no need to rewrite the program to work with multiple grids at all. Also, difficulties with constructing grid levels for an unstructured grid are avoided; agglomeration of cells is not used, and the number of faces per cell at coarse levels is not increased. In fact, this paper describes how to deploy a FAS MG accelerator in literally a week, even in code that is outdated from the point of view of software architecture.","PeriodicalId":55230,"journal":{"name":"Computational Mathematics and Mathematical Physics","volume":"249 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2023-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139036516","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

On a Particular Solution of the σ-Commutation Problem ( $$sigma ne 0, pm 1$$ ) for Toeplitz and Hankel Matrices 关于托普利兹矩阵和汉克尔矩阵的 σ-Commutation 问题 ( $$sigma ne 0, pm 1$$ ) 的特殊解法

IF 0.7 4区数学

Computational Mathematics and Mathematical Physics Pub Date : 2023-12-25 DOI: 10.1134/s0965542523110076

V. N. Chugunov, Kh. D. Ikramov

引用次数: 0

Analysis of the Influence of Quantum Effects on Optical Characteristics of Plasmonic Nanoparticles Based on the Discrete Sources Method 基于离散源方法的量子效应对等离子纳米粒子光学特性的影响分析

IF 0.7 4区数学

Computational Mathematics and Mathematical Physics Pub Date : 2023-12-25 DOI: 10.1134/s0965542523110088

Yu. A. Eremin, V. V. Lopushenko

引用次数: 0

A Fast Single-Pass Method for Solving the Generalized Eikonal Equation in a Moving Medium 解决移动介质中广义艾克纳方程的快速单通法

IF 0.7 4区数学

Computational Mathematics and Mathematical Physics Pub Date : 2023-12-25 DOI: 10.1134/s0965542523110118

M. S. Ho, J. S. Pak

{"title":"A Fast Single-Pass Method for Solving the Generalized Eikonal Equation in a Moving Medium","authors":"M. S. Ho, J. S. Pak","doi":"10.1134/s0965542523110118","DOIUrl":"https://doi.org/10.1134/s0965542523110118","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3>We develop a fast method for approximating the solution to the generalized eikonal equation in a moving medium. Our approach consists of the following two steps. First, we convert the generalized eikonal equation in a moving medium into a Hamilton–Jacobi–Bellman equation of anisotropic eikonal type for an anisotropic minimum-time control problem. Second, we modify the Neighbor–Gradient Single-pass method (NGSPM developed by Ho et al.), so that it not only suits the converted Hamilton–Jacobi–Bellman equation but also can be faster than original NGSPM. In the case of that Mach number is not comparable than 1, we compare our method and Characteristic Fast Marching Method (CFMM developed by Dahiya) via several numerical examples to show that our method is faster and more accurate than CFMM. We also compare the numerical solutions obtained from our method with the solutions obtained using the ray theory to show that our method captures the viscosity solution accurately even when the Mach number is comparable to 1. We also apply our method to 3D example to show that our method captures the viscosity solution accurately in 3D cases.","PeriodicalId":55230,"journal":{"name":"Computational Mathematics and Mathematical Physics","volume":"45 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2023-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139036522","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Analyticity and Pseudo-Analyticity in the Small Parameter Method 小参数法的解析性和伪解析性

IF 0.7 4区数学

Computational Mathematics and Mathematical Physics Pub Date : 2023-12-25 DOI: 10.1134/s096554252311012x

V. I. Kachalov, D. A. Maslov

引用次数: 0