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Numerical Simulation of MHD Peristaltic Flow with Variable Electrical Conductivity and Joule Dissipation Using Generalized Differential Quadrature Method

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Communications in Theoretical Physics 2019年第5期71卷 509-518页

作者： Muhammad Qasim Zafar Ali Abderrahim Wakif Zoubair Boulahia Department of mathematics COMSATS University Islamabad (CUI) Laboratory of mechanics Faculty of Sciences Ain Chock Hassan Ⅱ University

In this paper, the MHD peristaltic flow inside wavy walls of an asymmetric channel is investigated, where the walls of the channel are moving with peristaltic wave velocity along the channel length. During this investigation,the electrical conductivity both in Lorentz force and Joule heating is taken to be temperature dependent. Also, the long wavelength and low Reynolds number assumptions are utilized to reduce the governing partial differential equations into a set of coupled nonlinear ordinary differential equations. The new set of obtained equations is then numerically solved using the generalized differential quadrature method(GDQM). This is the first attempt to solve the nonlinear equations arising in the peristaltic flows using this method in combination with the Newton-Raphson technique. Moreover, in order to check the accuracy of the proposed numerical method, our results are compared with the results of built-in Mathematica command NDSolve. Taking Joule heating and viscous dissipation into account, the effects of various parameters appearing in the problem are used to discuss the fluid flow characteristics and heat transfer in the electrically conducting fluids graphically. In presence of variable electrical conductivity, velocity and temperature profiles are highly decreasing in nature when the intensity of the electrical conductivity parameter is strengthened.

关键词： peristaltic flow MHD variable electrical conductivity Joule dissipation generalized differential quadrature method(GDQM)

Vibration reduction evaluation of a linear system with a nonlinear energy sink under a harmonic and random excitation

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Applied mathematics and mechanics(English Edition) 2020年第1期41卷 1-14页

作者： Jiren XUE Yewei ZHANG Hu DING Liqun CHEN Shanghai Institute of Applied mathematics and mechanics Shanghai Key Laboratory of Mechanics in Energy EngineeringSchool of Mechanics and Engineering ScienceShanghai UniversityShanghai 200072China faculty of Aerospace Engineering Shenyang Aerospace UniversityShenyang 110136China

The nonlinear behaviors and vibration reduction of a linear system with a nonlinear energy sink(NES)are investigated.The linear system is excited by a harmonic and random base excitation,consisting of a mass block,a linear spring,and a linear viscous damper.The NES is composed of a mass block,a linear viscous damper,and a spring with ideal cubic nonlinear stiffness.Based on the generalized harmonic function method,the steady-state Fokker-Planck-Kolmogorov equation is presented to reveal the response of the system.The path integral method based on the Gauss-Legendre polynomial is used to achieve the numerical solutions.The performance of vibration reduction is evaluated by the displacement and velocity transition probability densities,the transmissibility transition probability density,and the percentage of the energy absorption transition probability density of the linear oscillator.The sensitivity of the parameters is analyzed for varying the nonlinear stiffness coefficient and the damper ratio.The investigation illustrates that a linear system with NES can also realize great vibration reduction under harmonic and random base excitations and random bifurcation may appear under different parameters,which will affect the stability of the system.

关键词： nonlinear energy sink(NES) Gauss-Legendre polynomial transmissibility percentage of energy absorption

Computer Oriented Numerical Scheme for Solving Engineering Problems

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Computer Systems Science & Engineering 2022年第8期42卷 689-701页

作者： Mudassir Shams Naila Rafiq Nasreen Kausar Nazir Ahmad Mir Ahmad Alalyani Department of Mathematica and Statistics Riphah International UniversityI-14Islamabad 44000Pakistan Department of mathematics NUMLIslamabad 44000Pakistan Department of mathematics Yildiz Technical UniversityFaculty of Arts and ScienceEsenler34210IstanbulTurkey Department of mathematics Faculty of Science and Arts in ALmandaqAl-Baha UniversityAl-BahaSaudi Arabia

In this study,we construct a family of single root finding method of optimal order four and then generalize this family for estimating of all roots of non-linear equation simultaneously.Convergence analysis proves that the local order of convergence is four in case of single root finding iterative method and six for simultaneous determination of all roots of non-linear equation.Some non-linear equations are taken from physics,chemistry and engineering to present the performance and efficiency of the newly constructed method.Some real world applications are taken from fluid mechanics,i.e.,fluid permeability in biogels and biomedical engineering which includes blood Rheology-Model which as an intermediate result give some nonlinear equations.These non-linear equations are then solved using newly developed simultaneous iterative schemes.Newly developed simultaneous iterative schemes reach to exact values on initial guessed values within given tolerance,using very less number of function evaluations in each step.Local convergence order of single root finding method is computed using CAS-Maple.Local computational order of convergence,CPU-time,absolute residuals errors are calculated to elaborate the efficiency,robustness and authentication of the iterative simultaneous method in its domain.

关键词： Biomedical engineering convergence order iterative method CPU-time simultaneous method

How do the landslide and non-landslide sampling strategies impact landslide susceptibility assessment? d A catchment-scale case study from China

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Journal of Rock mechanics and Geotechnical Engineering 2024年第3期16卷 877-894页

作者： Zizheng Guo Bixia Tian Yuhang Zhu Jun He Taili Zhang School of Civil and Transportation Engineering Hebei University of TechnologyTianjin300401China Hebei Key Laboratory of Earthquake Disaster Prevention and Risk Assessment Sanhe065201China faculty of Engineering China University of GeosciencesWuhan430074China Nanjing Center China Geological SurveyMinistry of Natural ResourcesNanjing210016China

The aim of this study is to investigate the impacts of the sampling strategy of landslide and non-landslide on the performance of landslide susceptibility assessment(LSA).The study area is the Feiyun catchment in Wenzhou City,Southeast China.Two types of landslides samples,combined with seven non-landslide sampling strategies,resulted in a total of 14 scenarios.The corresponding landslide susceptibility map(LSM)for each scenario was generated using the random forest model.The receiver operating characteristic(ROC)curve and statistical indicators were calculated and used to assess the impact of the dataset sampling strategy.The results showed that higher accuracies were achieved when using the landslide core as positive samples,combined with non-landslide sampling from the very low zone or buffer zone.The results reveal the influence of landslide and non-landslide sampling strategies on the accuracy of LSA,which provides a reference for subsequent researchers aiming to obtain a more reasonable LSM.

关键词： Landslide susceptibility Sampling strategy Machine learning Random forest China

Residual stress analysis of multi-pass cold spinning process

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Chinese Journal of Aeronautics 2022年第3期35卷 259-271页

作者： Zixuan LI Xuedao SHU faculty of Mechanical Engineering&mechanics Ningbo UniversityNingbo 315211China Zhejiang Provincial Key Laboratory of Part Rolling Technology Ningbo UniversityNingbo 315211China

Uncontrolled residual stresses have significant effects on the service time and defects of the spun parts.Nowadays,X-Ray Diffraction(XRD)method has been widely used in the residual stress measurement of industry products with different forming processes.The calculated residual stress is usually obtained from the data fitting slope of strain and angle with Ordinary Least Squares(OLS)method.But this fitting method is not always suitable for the big fluctuant data.In this paper,the Weighted Least Square(WLS)method is used for the data fitting and compared with the OLS method.The nickel-based superalloy GH3030 and iron-based superalloy GH1140 are applied in the multi-pass cold spinning experiments.The residual stress distributions of normal,potential crack and wrinkle workpieces are discussed with the grain structure.The results show that WLS method has better goodness of fit compared with OLS method.The residual stress distributions have special relationship with potential crack,wrinkle workpiece and grain structure.

关键词： Cold spinning process Data fitting Grain structure Potential crack Residual stress Weighted least square method

Regulating charge heterogeneity of lithium-ion battery via tab design toward maximizing extreme fast-charging performance

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Progress in Natural Science:Materials International 2023年第5期33卷 660-667页

作者： Jun Yang Yuzuo Wang Yanqing Hu Dengfeng Liu Bin Yang Dianbo Ruan Zhijun Qiao faculty of Mechanical Engineering and mechanics Ningbo University Institute of Advanced Energy Storage Technology and Equipment Ningbo University Hesheng Alternative Energy Technology Co. Ltd.

Construction of high-throughput electrical transmission structure via tab design is an effective way of developing high-power lithium-ion batteries(LIBs). In this paper, five types of 18650-cylindrical LIBs with different tab structures were prepared to analyze the mechanism of the effects of tab structure on battery performance,including internal resistance, C-rate performance, thermal and cycle. Research showed that the number of tabs and position were important factors, which strongly decided the internal resistance of battery. By adjusting tab structure, an extremely fast charging performance surpassing 10C can be achieved. Besides, the battery showed excellent cycle stability of more than 3000 cycles at 6C, which was proved to be due to optimizing the Li-ion concentration distribution of electrodes. The work also emphasized that excessive tabs contributed to no significant improvement in electrochemical performances at normal charging/discharging rates(<1C) for 18650 cells.The relationship between the operation conditions and tab design is established to further guide the manufacturing.

关键词： High-power lithium-ion batteries Tab structure Tabless electrolyte potential

Hydrodynamic Behavior of Fluid Resonance Between Twin Boxes in Moonpool with Various Edge Profiles Under Wave Actions

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中国海洋工程:英文版 2023年第4期37卷 547-557页

作者： LAN Jun-jie JIANG Sheng-chao GAO Jun-liang faculty of Vehicle Engineering and mechanics Dalian University of TechnologyDalian 116024China School of Naval Architecture and Ocean Engineering Jiangsu University of Science and TechnologyZhenjiang 212100China

Fluid resonance in moonpool formed by twin boxes under wave actions is investigated by using a viscous numerical wave flume with ReNormalization Group(RNG)turbulent model.The accuracy of the numerical model is validated by available experimental data.Three types of edge profiles,the sharp edge,concave edge and convex edge are con-sidered.Numerical simulations show that the normalized resonant amplitude in moonpool decreases with the decrease of moonpool opening or increase of incident wave amplitude.The increased reflection coefficients are the major reason for the phenomena,implying less wave energy is able to support the wave resonance in moonpool.With the increase of incident wave height,the energy coefficients increase for convex edges around resonant fre-quency,which are oppositely with those of sharp and concave edges.Various flow patterns of the wave resonance in the vicinity of the moonpool entrance are also identified,which are mainly dependent on the edge profiles.

关键词： moonpool wave resonance corner shape RNG turbulent model OpenFOAM® flow pattern

Transient analysis of a three-layer microbeam subjected to electric potential

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International Journal of Smart and Nano Materials 2017年第1期8卷 20-40页

作者： Mohammad Arefi Ashraf M.Zenkour Department of Solid mechanics Faculty of Mechanical EngineeringUniversity of KashanKashanIran Department of mathematics Faculty of ScienceKing Abdulaziz UniversityJeddahSaudi Arabia Department of mathematics Faculty of ScienceKafrelsheikh UniversityKafrelsheikhEgypt

In this paper,free vibration,wave propagation,and bending analyses of a sandwich microbeam integrated with piezoelectric face-sheets resting on Pasternak foundation under electric potential are presented based on the strain gradient theory and Euler–Bernoulli beam theory.The material properties of core are assumed variable along the thickness direction and piezoelectric face-sheets are assumed homogeneous piezoelectric materials.A two-dimensional electric potential distribution along the axial and transverse direction is applied on the face-sheets of microbeam.Hamilton principal is used to derive governing differential equations of motion.Three behaviors of sandwich microbeam including free vibration,wave propagation,and bending analyses are studied in this paper.Some numerical results are presented to capture the effect of important parameters of the problem such as in-homogeneous index,applied voltage,parameters of foundation,and material length scales.The numerical results indicate that the effect of electric potential along the axial direction is very small rather than one along the transverse direction where initial voltage is applied.

关键词： Euler–Bernoulli three-layer microbeam free vibration wave propagation electric potential applied voltage

Derivations of Skew PBW-Extensions

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Communications in mathematics and Statistics 2015年第4期3卷 449-457页

作者： V.A.Artamonov Department of Algebra Faculty of Mechanics and MathematicsMoscow State UniversityMoscowRussia

The paper contains a classification of derivations of skew PBW-extensions of rings.

关键词： Derivations Skew polynomial extensions PBW-extensions