IF 2 3区数学

Axioms Pub Date : 2024-03-31 DOI: 10.3390/axioms13040230

Yulei Chen, Dongwei Guo

引用次数: 0

Numerical Simulation of Flows Using the Fourier Pseudospectral Method and the Immersed Boundary Method 使用傅立叶伪谱法和沉浸边界法对流动进行数值模拟

IF 2 3区数学

Axioms Pub Date : 2024-03-30 DOI: 10.3390/axioms13040228

Laura Augusta Vasconcelos de Albuquerque, M.F.S. Villela, F. Mariano

{"title":"Numerical Simulation of Flows Using the Fourier Pseudospectral Method and the Immersed Boundary Method","authors":"Laura Augusta Vasconcelos de Albuquerque, M.F.S. Villela, F. Mariano","doi":"10.3390/axioms13040228","DOIUrl":"https://doi.org/10.3390/axioms13040228","url":null,"abstract":"The present work proposes the application of a computational methodology based on the coupling of the Fourier Pseudospectral Method (FPSM) and the Immersed Boundary Method (IBM) for conducting flow simulations over slender airfoils. This methodology, termed IMERSPEC, leverages the benefits of both high accuracy and low computational cost inherent in pseudospectral methods, thanks to the utilization of the Fast Fourier Transform algorithm. IBM is employed to impose non-periodic boundary conditions in the Navier–Stokes equations, addressing the requirement of periodicity at boundaries for FPSM convergence and to accurately represent the immersed slender airfoil in the flow. The aerodynamic behavior of the analyzed profiles was assessed by calculating lift and drag coefficients, which were then compared with existing literature results. Consistently favorable outcomes were observed, particularly in flows at lower Reynolds numbers, demonstrating the effectiveness of the IMERSPEC methodology for simulating complex flows computationally. Additionally, weight functions, fundamental to IBM, are employed flexibly for aerodynamic force calculations. Specifically, within the same simulation, a Cubic function is utilized for drag calculation while a Hat function is employed for lift calculation, yielding results more closely aligned with the literature’s findings. This approach offers an alternative to previously proposed methods for IBM implementation.","PeriodicalId":53148,"journal":{"name":"Axioms","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140363476","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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

Two Different Analytical Approaches for Solving the Pantograph Delay Equation with Variable Coefficient of Exponential Order 解决具有指数级可变系数的受电弓延迟方程的两种不同分析方法

IF 2 3区数学

Axioms Pub Date : 2024-03-30 DOI: 10.3390/axioms13040229

Reem Alrebdi, Hind K. Al-Jeaid

{"title":"Two Different Analytical Approaches for Solving the Pantograph Delay Equation with Variable Coefficient of Exponential Order","authors":"Reem Alrebdi, Hind K. Al-Jeaid","doi":"10.3390/axioms13040229","DOIUrl":"https://doi.org/10.3390/axioms13040229","url":null,"abstract":"The pantograph equation is a basic model in the field of delay differential equations. This paper deals with an extended version of the pantograph delay equation by incorporating a variable coefficient of exponential order. At specific values of the involved parameters, the exact solution is obtained by applying the regular Maclaurin series expansion (MSE). A second approach is also applied on the current model based on a hybrid method combining the Laplace transform (LT) and the Adomian decomposition method (ADM) denoted as (LTADM). Although the MSE derives the exact solution in a straightforward manner, the LTADM determines the solution in a closed series form which is theoretically proved for convergence. Further, the accuracy of such a closed-form solution is examined through various comparisons with the exact solution. For validation, the residual errors are calculated and displayed in graphs. The results show that the solution obtained utilizing the LTADM is in full agreement with the exact solution using only a few terms of the closed-form series solution. Moreover, it is found that the residual errors tend to zero, which reflects the effectiveness of the LTADM. The present approach may merit further extension by including other types of linear delay differential equations with variable coefficients.","PeriodicalId":53148,"journal":{"name":"Axioms","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140361774","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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

Unit Maxwell-Boltzmann Distribution and Its Application to Concentrations Pollutant Data 单元麦克斯韦-玻尔兹曼分布及其在污染物浓度数据中的应用

IF 2 3区数学

Axioms Pub Date : 2024-03-29 DOI: 10.3390/axioms13040226

Cenker Biçer, H. Bakouch, Hayrinisa Demirci Biçer, Gadir Alomair, Tassaddaq Hussain, Amal Almohisen

{"title":"Unit Maxwell-Boltzmann Distribution and Its Application to Concentrations Pollutant Data","authors":"Cenker Biçer, H. Bakouch, Hayrinisa Demirci Biçer, Gadir Alomair, Tassaddaq Hussain, Amal Almohisen","doi":"10.3390/axioms13040226","DOIUrl":"https://doi.org/10.3390/axioms13040226","url":null,"abstract":"In the vast statistical literature, there are numerous probability distribution models that can model data from real-world phenomena. New probability models, nevertheless, are still required in order to represent data with various spread behaviors. It is a known fact that there is a great need for new models with limited support. In this study, a flexible probability model called the unit Maxwell-Boltzmann distribution, which can model data values in the unit interval, is derived by selecting the Maxwell-Boltzmann distribution as a base-line model. The important characteristics of the derived distribution in terms of statistics and mathematics are investigated in detail in this study. Furthermore, the inference problem for the mentioned distribution is addressed from the perspectives of maximum likelihood, method of moments, least squares, and maximum product space, and different estimators are obtained for the unknown parameter of the distribution. The derived distribution outperforms competitive models according to different fit tests and information criteria in the applications performed on four actual air pollutant concentration data sets, indicating that it is an effective model for modeling air pollutant concentration data.","PeriodicalId":53148,"journal":{"name":"Axioms","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140365764","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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

New Developments in Geometric Function Theory II 几何函数论的新发展 II

IF 2 3区数学

Axioms Pub Date : 2024-03-28 DOI: 10.3390/axioms13040224

G. Oros

引用次数: 0

Weak Sharp Type Solutions for Some Variational Integral Inequalities 一些变分积分不等式的弱夏普式解法

IF 2 3区数学

Axioms Pub Date : 2024-03-28 DOI: 10.3390/axioms13040225

S. Treanțǎ, Tareq Saeed

引用次数: 0

An Optimal Property of B-Bases for the Modified Richardson Method 修正理查德森方法的 B 基最佳特性

IF 2 3区数学

Axioms Pub Date : 2024-03-27 DOI: 10.3390/axioms13040223

Juan Manuel Peña

引用次数: 0

Iteration with Bisection to Approximate the Solution of a Boundary Value Problem 用分段迭代法近似求解边界值问题

IF 2 3区数学

Axioms Pub Date : 2024-03-27 DOI: 10.3390/axioms13040222

R. Avery, D. Anderson, Jeffrey Lyons

引用次数: 0

Solving a Multimodal Routing Problem with Pickup and Delivery Time Windows under LR Triangular Fuzzy Capacity Constraints 在 LR 三角模糊容量约束条件下解决带有取货和送货时间窗口的多式联运路由问题

IF 2 3区数学

Axioms Pub Date : 2024-03-26 DOI: 10.3390/axioms13040220

Jie Ge, Y. Sun

{"title":"Solving a Multimodal Routing Problem with Pickup and Delivery Time Windows under LR Triangular Fuzzy Capacity Constraints","authors":"Jie Ge, Y. Sun","doi":"10.3390/axioms13040220","DOIUrl":"https://doi.org/10.3390/axioms13040220","url":null,"abstract":"This study models a container routing problem using multimodal transportation to improve its economy, timeliness, and reliability. Pickup and delivery time windows are simultaneously formulated in optimization to provide the shipper and the receiver with time-efficient services, in which early pickup and delayed delivery can be avoided, and nonlinear storage periods at the origin and the destination can be minimized. Furthermore, the capacity uncertainty of the multimodal network is incorporated into the advanced routing to enhance its reliability in practical transportation. The LR triangular fuzzy number is adopted to model the capacity uncertainty, in which its spread ratio is defined to measure the uncertainty level of the fuzzy capacity. Due to the nonlinearity introduced by the time windows and the fuzziness from the network capacity, this study establishes a fuzzy nonlinear optimization model for optimization problem. A chance-constrained linear reformulation equivalent to the proposed model is then generated based on the credibility measure, which makes the global optimum solution attainable by using Lingo software. A numerical case verification demonstrates that the proposed model can effectively solve the problem. The case analysis points out that the formulation of pickup and delivery time windows can improve the timeliness of the entire transportation process and help to achieve on-time transportation. Furthermore, improving the confidence level and the uncertainty level increases the total costs of the optimal route. Therefore, the shipper and the receiver must prepare more transportation budget to improve reliability and address the increasing uncertainty level. Further analysis draws some insights to help the shipper, receiver, and multimodal transport operator to organize a reliable and cost-efficient multimodal transportation under capacity uncertainty through confidence level balance and transportation service and transfer service selection.","PeriodicalId":53148,"journal":{"name":"Axioms","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140378935","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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

Bidiagonal Factorizations of Filbert and Lilbert Matrices 菲尔伯特和利尔伯特矩阵的对角因式分解

IF 2 3区数学

Axioms Pub Date : 2024-03-26 DOI: 10.3390/axioms13040219

Yasmina Khiar, E. Mainar, Juan Manuel Peña, Eduardo Royo-Amondarain, B. Rubio

引用次数: 0

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