Journal of Engineering Mathematics最新文献_第6页

Performance optimization of generator in steam turbine power plants using computational intelligence techniques 利用计算智能技术优化蒸汽轮机发电厂发电机的性能

IF 1.3 4区工程技术

Journal of Engineering Mathematics Pub Date : 2024-03-25 DOI: 10.1007/s10665-024-10342-6

Ashish Kumar, Deepak Sinwar, Naveen Kumar, Monika Saini

{"title":"Performance optimization of generator in steam turbine power plants using computational intelligence techniques","authors":"Ashish Kumar, Deepak Sinwar, Naveen Kumar, Monika Saini","doi":"10.1007/s10665-024-10342-6","DOIUrl":"https://doi.org/10.1007/s10665-024-10342-6","url":null,"abstract":"A generator is the crucial subsystem of steam turbine power plants. Its configuration is very complex, as it is assembled using seven different subsystems. The key objective of the present investigation is to develop an efficient stochastic model for generators under the concepts of cold standby redundancy and exponentially distributed failure and repair laws. The subsystem, namely the cooling and exhaust units, has the provision of cold standby redundancy. For this purpose, a novel stochastic model is proposed using the Markovian methodology, and Chapman–Kolmogorov differential–difference equations are derived. The switch devices are considered perfect, and units after repair work are considered new. To predict the optimal availability and profit of the proposed model, computational intelligence techniques, namely grey wolf optimization, whale optimization algorithm, moth-flame optimizer, dragonfly algorithm, grasshopper optimization algorithm, sine cosine algorithm, black hole algorithm, and ant lion algorithm are used. The impact of various numbers of iterations and population sizes is investigated on the availability, profit, and decision variables of the generator unit. It is revealed that the whale optimization algorithm predicts optimal availability of 0.9999905 after 10 iterations, while in a particular case, the optimal profit is 7199.924. The derived expressions of failure and repair rates, availability, and profit function are useful for system designers and maintenance engineers to design and plan maintenance strategies for generators and steam turbine power plants.","PeriodicalId":50204,"journal":{"name":"Journal of Engineering Mathematics","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2024-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140301002","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Hydrodynamic of surge radiation by a floating cylinder in the presence of bottom-mounted cylindrical obstacle in a two-layer fluid system 在双层流体系统中，当底部安装有圆柱形障碍物时，浮动圆柱体的浪涌辐射流体力学问题

IF 1.3 4区工程技术

Journal of Engineering Mathematics Pub Date : 2024-03-25 DOI: 10.1007/s10665-024-10339-1

Champak Kr. Neog, Mohammad Hassan

{"title":"Hydrodynamic of surge radiation by a floating cylinder in the presence of bottom-mounted cylindrical obstacle in a two-layer fluid system","authors":"Champak Kr. Neog, Mohammad Hassan","doi":"10.1007/s10665-024-10339-1","DOIUrl":"https://doi.org/10.1007/s10665-024-10339-1","url":null,"abstract":"In this study, the effects of the surge radiation force are investigated by a floating cylinder in two-layer fluid over a bottom-mounted cylinder. The proposed device consists of a floating cylinder in the upper layer and another a coaxial bottom cylinder in the lower layer of a two-layer fluid system of finite depth having the infinite horizontal extent. The radiation problem is taken into consideration under the framework of linear water wave and the entire fluid domain is divided into two regions, say, an exterior and interior regions. The analytical solutions for the surge radiation potential to the boundary-value problems in the respective regions are obtained by utilizing the method of separation of variables. By making use of the matched eigenfunction expansion method, the unknown coefficients that arise in the radiation potentials are evaluated. With the help of the expressions of the surge radiated potential, the corresponding radiation forces are obtained as a linear combination of added mass and damping coefficient. A bunch of numeric outcomes of added mass and damping coefficient are investigated for a distinct set of parameters of the device, i.e., the effect of the variation in frequencies with the radii of the cylinders, drafts of the floating cylinder, and the density ratio between the fluid layers on the surge radiated force are presented and their significant results are discussed. The 3D free surface and interface elevations due to the effect of surge radiated waves are presented in both surface- and internal-wave modes. The oscillations in added mass and damping coefficients are observed with variations of the parameters of the device.","PeriodicalId":50204,"journal":{"name":"Journal of Engineering Mathematics","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2024-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140301207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Nonstandard finite difference schemes for linear and non-linear Fokker–Planck equations 线性和非线性福克-普朗克方程的非标准有限差分方案

IF 1.3 4区工程技术

Journal of Engineering Mathematics Pub Date : 2024-03-23 DOI: 10.1007/s10665-024-10346-2

A. S. Neena, Dominic P. Clemence-Mkhope, Ashish Awasthi

引用次数: 0

Thermal stresses in an orthotropic hollow sphere under thermal shock: a unified generalized thermoelasticity 各向同性空心球在热冲击下的热应力：统一的广义热弹性

IF 1.3 4区工程技术

Journal of Engineering Mathematics Pub Date : 2024-03-19 DOI: 10.1007/s10665-023-10321-3

Mehdi Soroush, Mohammad Soroush

引用次数: 0

On the discrepancies between POD and Fourier modes on aperiodic domains 关于非周期性域上 POD 与傅里叶模式之间的差异

IF 1.3 4区工程技术

Journal of Engineering Mathematics Pub Date : 2024-03-19 DOI: 10.1007/s10665-024-10340-8

Azur Hodžić, Peder J. Olesen, Clara M. Velte

{"title":"On the discrepancies between POD and Fourier modes on aperiodic domains","authors":"Azur Hodžić, Peder J. Olesen, Clara M. Velte","doi":"10.1007/s10665-024-10340-8","DOIUrl":"https://doi.org/10.1007/s10665-024-10340-8","url":null,"abstract":"The application of Fourier analysis in combination with the Proper Orthogonal Decomposition (POD) is investigated. In this approach to turbulence decomposition, which has recently been termed Spectral POD (SPOD), Fourier modes are considered as solutions to the corresponding Fredholm integral equation of the second kind along homogeneous-periodic or homogeneous coordinates. In the present work, the notion that the POD modes formally converge to Fourier modes for increasing domain length is challenged. A family of analytical correlation functions parametrized by the Taylor macro/micro scale ratio (MMSR) is investigated numerically. The results of the analysis indicate that the discrepancy between POD and Fourier modes along locally translationally invariant coordinates is coupled to the MMSR of the flow. Increasing discrepancies are observed for smaller MMSRs, which are characteristic of low Reynolds number flows. The asymptotic convergence rate of the eigenspectrum matches the corresponding convergence rate of the exact analytical Fourier spectrum of the kernel in question, even for extremely small domains and small MMSRs where the corresponding DFT spectra suffer heavily from windowing effects. The Taylor micro scales are consistently underestimated when reconstructed using Fourier modes—failing to converge to the correct value even if all Fourier modes are used—while these are accurately reconstructed using POD modes.","PeriodicalId":50204,"journal":{"name":"Journal of Engineering Mathematics","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2024-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140171333","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Solving convex uncertain PDE-constrained multi-dimensional fractional control problems via a new approach 用新方法解决凸不确定 PDE 受限多维分数控制问题

IF 1.3 4区工程技术

Journal of Engineering Mathematics Pub Date : 2024-03-16 DOI: 10.1007/s10665-024-10338-2

Anurag Jayswal, Ayushi Baranwal, Tadeusz Antczak

引用次数: 0

Adaptive backstepping control for sensor-less haptic joysticks with uncertainty parameters 具有不确定性参数的无传感器触觉操纵杆的自适应反步进控制

IF 1.3 4区工程技术

Journal of Engineering Mathematics Pub Date : 2024-03-11 DOI: 10.1007/s10665-024-10341-7

Tao Ni, Panhong Zhang, Zeren Zhao

引用次数: 0

A radial integration displacement discontinuity method with discontinuous isoparametric elements for 3D fracture simulations 采用非连续等参数元素的径向积分位移不连续法进行三维断裂模拟

IF 1.3 4区工程技术

Journal of Engineering Mathematics Pub Date : 2024-03-11 DOI: 10.1007/s10665-024-10335-5

Ke Li, Fei Wang

{"title":"A radial integration displacement discontinuity method with discontinuous isoparametric elements for 3D fracture simulations","authors":"Ke Li, Fei Wang","doi":"10.1007/s10665-024-10335-5","DOIUrl":"https://doi.org/10.1007/s10665-024-10335-5","url":null,"abstract":"To improve the accuracy of displacement discontinuity method and enhance its adaptivity, a general-purpose 3D displacement discontinuity method with both linear and quadratic isoparametric elements has been developed to model engineering problems where discontinuous surfaces such as cracks are involved. Linear and quadratic isoparametric elements have linear and quadratic distributions of displacement discontinuity values, respectively. Both of them belong to discontinuous elements, in which the geometry shape functions are different from the interpolation shape functions. The new general formulation, based on the boundary integral functions, is given for displacement discontinuity problems with arbitrary boundary shapes. This formulation contains hypersingular integrals which can be evaluated in the sense of Hadamard principal value. The radial integration technique is applied to perform these singular integrals with sufficiently high accuracy. Various numerical examples including stress intensity factor calculation are given to validate the accuracy of the proposed approach. Compared with the constant displacement discontinuity element, the present isoparametric displacement discontinuity elements show better accuracy.","PeriodicalId":50204,"journal":{"name":"Journal of Engineering Mathematics","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2024-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140098241","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Analyses of aerodynamic forces on a three-dimensional pitching plate above surface waves 面波上方三维俯仰板上的空气动力分析

IF 1.3 4区工程技术

Journal of Engineering Mathematics Pub Date : 2024-03-11 DOI: 10.1007/s10665-024-10337-3

Meng-Yu Lin

{"title":"Analyses of aerodynamic forces on a three-dimensional pitching plate above surface waves","authors":"Meng-Yu Lin","doi":"10.1007/s10665-024-10337-3","DOIUrl":"https://doi.org/10.1007/s10665-024-10337-3","url":null,"abstract":"Since a floating solar panel is set above a water surface, the ground effect due to the small gap between the panel and the free surface may be induced by the wind load, in turn causing a high lift force on the panel. In this paper, the wind load on a three-dimensional thin flat plate floating on surface waves is studied analytically under linear assumptions. The clearance between the panel and the free surface is set to be smaller than the panel length and the effects of the base of the floating system are ignored. The pitch motion of the plate due to linear surface waves is considered and the effects of the aspect ratio of the plate, wave number, and wave speed of the free surface are discussed. The analytical solution shows that, if the plate is stationary and the free surface is flat (no waves), then the lift coefficient increases with aspect ratio. For a pitching plate above surface waves, lift coefficient increases with aspect ratio for longer wavelengths, but decreases when the aspect ratio increases for shorter wavelengths. Minimum lift and the associated wave number and aspect ratio for different wave speeds are also discussed. The findings of this study are anticipated to enhance the design of floating solar panels, improving their capacity to withstand substantial wind and waves.","PeriodicalId":50204,"journal":{"name":"Journal of Engineering Mathematics","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2024-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140098337","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Scattering of plane SH waves by a concentric semi-cylindrical discontinuity and canyon 同心半圆柱形不连续面和峡谷对平面 SH 波的散射

IF 1.3 4区工程技术

Journal of Engineering Mathematics Pub Date : 2024-02-29 DOI: 10.1007/s10665-024-10334-6

Zhiwen Li

{"title":"Scattering of plane SH waves by a concentric semi-cylindrical discontinuity and canyon","authors":"Zhiwen Li","doi":"10.1007/s10665-024-10334-6","DOIUrl":"https://doi.org/10.1007/s10665-024-10334-6","url":null,"abstract":"The discontinuity of the medium and the irregularity of the ground significantly affect the propagation of seismic waves. However, the comprehensive effects of these two factors on seismic motion have not yet been fully investigated. To reveal the mechanism of dynamic interaction between the discontinuity and the irregular topography, this study provides a series of solution for the scattering of plane SH waves caused by a concentric semi-cylindrical discontinuity and canyon in an elastic half-space, using the displacement discontinuity model and the wave function expansion method. Based on the proposed series solution, a systematic analysis is conducted to investigate the influences of the stiffness of the discontinuity, the radius ratio between the discontinuity and the canyon, and the properties (e.g., frequency and angle) of the incident wave on the ground motion and underground motion. The results indicate that the stiffness of the discontinuity is a key factor determining the distribution of seismic motion. A high stiffness leads to a distribution similar to that of the canyon alone, while a low stiffness results in a much more complex distribution.","PeriodicalId":50204,"journal":{"name":"Journal of Engineering Mathematics","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2024-02-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140006921","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0