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The Study of Electromagnetic Scattering by a Non-perfectly Conductor in Chiral Media by potential theory

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Communications in Mathematical Research 2012年第3期28卷 235-242页

作者： GAO TIAN-LING LIU QIANG College of Mathematics and Computational Science Shenzhen University Shenzhen Guangdong 510275

This paper is concerned with the electromagnetic scattering by a nonperfectly conductor obstacle in chiral environment. A two-dimensional mathematical model is established. The existence and uniqueness of the problem ... 详细信息

关键词： chiral medium MaxweU's equation Drude-Born-Fedorov equation potential theory

Comparison of potential theory and Morison Equation for Deformable Horizontal Cylinders

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Sustainable Marine Structures 2022年第2期4卷 1-10页

作者： Chungkuk Jin Department of Ocean Engineering Texas A&M UniversityTexasthe United States

This study investigates the hydro-elastic behaviors of fully submerged horizontal cylinders in different regular *** methods were proposed and compared in this *** first method was based on potential theory in frequency domain and the discrete-module-beam(DMB)method,which discretizes a floating elastic structure into a sufficient number of rigid bodies while simultaneously representing the elastic behavior from beam elements with Euler-Bernoulli beam and Saint-Venant ***,the Morison method in time domain was employed;this method estimates wave forces from the semi-empirical Morison equation,and the elastic behavior is embodied by massless axial,bending,and torsional *** parametric studies on cylinder diameter,submergence depth,and wave direction were *** forces,dry/wet mode shapes/natural frequencies,and dynamic motions are presented and analyzed.

关键词： Wave force Discrete-module-beam method potential theory Morison equation Horizontal cylinder

Computation of Ship Hydrodynamic Interaction Forces in Restricted Waters using potential theory

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Journal of Marine Science and Application 2012年第3期11卷 265-275页

作者： Xueqian Zhou Serge Sutulo C. Guedes Soares Centre for Marine Technology and Engineering (CENTEC) Instituto Superior Toenico Technical University of Lisbon Lisboa 1049-001 Portugal

A computer code based on the double-body potential flow model and the classic source panel method has been developed to study various problems of hydrodynamic interaction between ships and other objects with solid boundaries including the seabed. A peculiarity of the proposed implementation is the application of the so-called ＂moving-patch＂ method for simulating steady boundaries of large extensions. The method is based on an assumption that at any moment just the part of the boundary （＂moving patch＂） which lies close to the interacting ship is significant for the near-field interaction. For a specific case of the fiat bottom, comparative computations were performed to determine optimal dimensions of the patch and of the constituting panels based on the trade-off between acceptable accuracy and reasonable efficiency. The method was applied to estimate the sway force on a ship hull moving obliquely across a dredged channel. The method was validated for a case of ship-to-ship interaction when tank data were available. This study also contains a description of a newly developed spline approximation algorithm necessary for creating consistent discretizations of ship hulls with various degrees of refinement.

关键词： ship hydrodynamic interaction restricted waters moving panelled patch method potential theory

ON SOURCE ANALYSIS BY WAVE SPLITTING WITH APPLICATIONS IN INVERSE SCATTERING OF MULTIPLE OBSTACLES

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Journal of Computational Mathematics 2007年第3期25卷 266-281页

作者： Fahmi ben Hassen Jijun Liu Roland Potthast Laboratoire de Modelisation Mathematique et Numerique dans les Sciences de l'Ingenieur ENIT-University of Tunis-El Manar BP 37 1002 Tunis Tunisia Department of Mathematics Southeast University Nanjing 210096 China University of Reading Department of Mathematics Whiteknights PO Box 220 Berkshire RG6 6AX UK

We study wave splitting procedures for acoustic or electromagnetic scattering problems. The idea of these procedures is to split some scattered field into a sum of fields coming from different spatial regions such that this information can be used either for inversion algo- rithms or for active noise control. Splitting algorithms can be based on general boundary layer potential representation or Green＇s representation formula. We will prove the unique decomposition of scattered wave outside the specified reference domain G and the unique decomposition of far-field pattern with respect to different reference domain G. Further, we employ the splitting technique for field reconstruction for a scatterer with two or more separate components, by combining it with the point source method for wave recovery. Us-ing the decomposition of scattered wave as well as its far-field pattern, the wave splitting procedure proposed in this paper gives an efficient way to the computation of scattered wave near the obstacle, from which the multiple obstacles which cause the far-field pattern can be reconstructed separately. This considerably extends the range of the decomposition methods in the area of inverse scattering. Finally, we will provide numerical examples to demonstrate the feasibility of the splitting method.

关键词： Inverse scattering Wave splitting potential theory Near field Regularization.

Theoretical Approximation of Focusing-Wave Induced Load upon A Large-Scale Vertical Cylinder

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China Ocean Engineering 2017年第5期31卷 598-606页

作者： XUE Hong-xiang HU Zhe TANG Wen-yong ZHANG Xiao-ying WANG Kun-peng State Key Laboratory of Ocean Engineering Shanghai Jiao Tong University Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration Key Laboratory of Ships and Ocean Engineering of Fujian Province Jimei University School of Naval Architecture and Ocean Engineering Jiangsu University of Science and Technology

Until now, most researches into the rogue-wave-structure interaction have relied on experimental measurement and numerical simulation. Owing to the complexity of the physical mechanism of rogue waves, theoretical study on the wave-structure issue still makes little progress. In this paper, the rogue wave flow around a vertical cylinder is analytically studied within the scope of the potential theory. The rogue wave is modeled by the Gauss envelope, which is one particular case of the well-known focusing theory. The formulae of the wave-induced horizontal force and bending moment are proposed. For the convenience of engineering application, the derived formulae are simplified appropriately, and verified against numerical results. In addition, the influence of wave parameters, such as the energy focusing degree and the wave focusing position, is thoroughly investigated.

关键词： rogue wave Gauss envelope upright cylinder potential theory analytical approximation

A PENNY-SHAPED CRACK IN A TRANSVERSELY ISOTROPIC PIEZOELECTRIC SOLID:MODES Ⅱ AND Ⅲ PROBLEMS

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Acta Mechanica Sinica 1999年第1期15卷 52-58页

作者：陈伟球丁皓江 Department of Civil Engineering Zhejiang UniversityHangzhou 310027China

An exact analysis of the modes Ⅱ and Ⅲ problems of a penny- shaped crack in a transversely isotropic piezoelectric medium is performed in this *** potential theory method is employed based on the general solution of three-dimensional piezoelasticity and the four harmonics involved are represented by one complex *** results in potential theory are then utilized to obtain the exact solution that is expressed in terms of elementary *** is made between the current results with those published and good agreement is obtained.

关键词： transversely isotropic piezoelectric material general solution potential theory penny-shaped crack modes Ⅱ and Ⅲ

Some recent advances in 3D crack and contact analysis of elastic solids with transverse isotropy and multifield coupling

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Acta Mechanica Sinica 2015年第5期31卷 601-626页

作者： Wei-Qiu Chen Department of Engineering Mechanics Zhejiang University

Significant progress has been made in mixed boundary-value problems associated with three-dimensional（3D） crack and contact analyses of advanced materials featuring more complexities compared to the conventional isotropic elastic *** include material anisotropy and multifield coupling,two typical characteristics of most current multifunctional *** this paper we try to present a state-of-the-art description of 3D exact/analytical solutions derived for crack and contact problems of elastic solids with both transverse isotropy and multifield coupling in the latest decade by the potential theory method in the spirit of *** ingenious breakthrough brings new vigor and vitality to the old research subject of classical potential *** are particularly interested in crack and contact problems with certain nonlinear *** is also placed on the coupling between the temperature field（or the like） and other physical fields（e.g.,elastic,electric,and magnetic fields）.We further highlight the practical significance of 3D contact solutions,in particular in applications related to modern scanning probe microscopes.

关键词： Crack Contact Mixed boundary-value problem Transverse isotropy Multifield coupling potential theory Exact solution Scanning probe microscope

Investigation of Motion of Two Hinged Bodies Moored by Mooring Lines in Waves

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China Ocean Engineering 2002年第2期17卷 193-200页

作者： JI Hengteng(纪亨腾) FAN Ju(范菊) HUANG Xianglu(黄祥鹿) School of Naval Architecture and Ocean Engineering Shanghai Jiao Tong Unitersity Shanghai 200030 China School of Naval Architecture and Ocean Engineering Shanghai Jiao Tong Unitersity Shanghai 200030 China School of Naval Architecture and Ocean Engineering Shanghai Jiao Tong Unitersity Shanghai 200030 China

In this paper, the motions are studied of a multi-body which is composed of two plates hinged together and moored by eight mooring lines in regular waves. The experimental results are compared with computational results. The linear potential theory and the perturbation method are combined to study this complicated system. The former is used to calculate the wave forces acting on the plates and the motion responses of them, while the latter is used to describe the dynamic character of the eight mooring lines coupled with the two hinged plates. Some response results of each plate are presented and comparisons between calculated results and experimental data are given. All the calculations are confined to regular beam waves.

关键词： potential theory motion responses perturbation method hydrodynamics wave force mooring lines

Research on Motion Performance of the Mobile Double-Causeway Pier System

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China Ocean Engineering 2008年第2期22卷 267-276页

作者：余建星田佳徐金利张翼飞杨晓蓉谭振东董文斌杜尊峰 Key Laboratory of Port and Ocean Engineering Tianjin University Jinghai Bureau of Communications Military Transportation Institute

Mobile offshore double-causeway pier system, a type of seashore unloading equipment, consists of two groups of multiple connected semi-submersible modules. This structure has wide application because most of the middle or mini type of vessels and ships can be moored to it. Based on the analysis of computational methods of multi-body motion response, a hydrodynamic model is set up and the three-dimensional potential theory in finite depth is adopted to calculate the three-dimensional motion response of this system. The double P-M spectrum is used to analyze the motion response in irregular waves. Different wave directions are specially taken into consideration, due to their various effects to the motion response. Furthermore, the calculated result is compared with that of the experiment, and it is proved that sway, heave, pitch and yaw motion are greatly constrained by mooring system. The comparison also indicates that the model can forecast the motion performance of the target, and that the calculated result can also be used as reference in connector and mooring system design.

关键词： offshore mobile pier system multi-floating body potential theory double P-M spectrum hydrodynamic analysis