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SURFACE AND INTERFACIAL GRAVITY WAVES INDUCED BY AN IMPULSIVE DISTURBANCE IN A TWO-LAYER INVISCID FluID

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Journal of Hydrodynamics 2009年第1期21卷 26-33页

作者： lu dong-qiang CHEN Ting-ting Shanghai Institute of Applied Mathematics and Mechanics Shanghai University Shanghai 200072 China

The transient gravity waves due to an impulsive source in a two-layer fluid system are investigated analytically. The fluid is assumed to be inviscid and incompressible. The density of each of the two layers is constant. Five different boundary conditions are considered. The depth of each of the two layers is infinite or finite. The upper fluid of finite depth is covered by a rigid lid or a free surface. Based on the assumption of small-amplitude waves, a linear system is established. The integral solutions for the free-surface and interfacial waves are obtained by means of the Fourier-Laplace transform. The corresponding asymptotic representations are derived for large time with a fixed distance-to-time ratio by the Stokes and Scorer methods of stationary phase. The analytical solutions show that there are two different modes, namely the free-surface and interracial wave modes. The wave profiles observed depend on the relation between the distance-to-time ratio and the maximal group velocities and on the limiting values of the second derivatives of the frequencies as well.

关键词： impulsive disturbances imerfacial waves free surface waves stationary-phase methods

FLEXURAL-GRAVITY WAVES DUE TO TRANSIENT DISTURBANCES IN AN INVISCID FluID OF FINITE DEPTH

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Journal of Hydrodynamics 2008年第2期20卷 131-136页

作者： lu dong-qiang LE Jia-chun DAI Shi-qiang Shanghai Institute of Applied Mathematics and Mechanics Shanghai University Shanghai 200072 China Shanghai Key Laboratory of Mechanics in Energy and Environment Engineering Shanghai 200072 China

The dynamic response of an ice-covered fluid to transient disturbances was analytically investigated by means of integral transforms and the generalized method of stationary phase. The initially quiescent fluid of finite depth was assumed to be inviscid, incompressible, and homogenous. The thin ice-cover was modeled as a homogeneous elastic plate. The disturbances were idealized as the fundamental singularities. A linearized initial-boundary-value problem was formulated within the framework of potential flow. The perturbed flow was decomposed into the regular and the singular components. An image system was introduced for the singular part to meet the boundary condition at the fiat bottom. The solutions in integral form for the vertical deflexion at the ice-water interface were obtained by means of a joint Laplace-Fourier transform. The asymptotic representations of the wave motion were explicitly derived for large time with a fixed distance-to-time ratio. The effects of the finite depth of fluid on the resultant wave pattems were discussed in detail. As the depth increases from zero, the critical wave number and the minimal group velocity first increase to their peak values and then decrease to constants.

关键词： waves ice-cover transient disturbances asymptotic group velocity

NUMERICAL SIMULATION OF TWO-DIMENSIONAL DAM-BREAK FLOWS IN CURVED CHANNELS

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Journal of Hydrodynamics 2007年第6期19卷 726-735页

作者： BAI Yu-chuan XU dong lu dong-qiang Institute for Sediment on River and Coast 300072 China Shanghai Institute of Applied Mathematics Engineering School of Civil Engineering Tianjin University Tianjin and Mechanics Shanghai University Shanghai 200072 China

Two-dimensional transient dam-break flows in a river with bends were theoretically studied. The river was modeled as a curved channel with a constant width and a flat bottom. The water was assumed to be an incompressible and homogeneous fluid. A channel-fitted orthogonal curvilinear coordinate system was established and the corresponding two-dimensional shallow-water equations were derived for this system. The governing equations with well-posed initial and boundary conditions were numerically solved in a rectangular domain by use of the Godunov-type finite-difference scheme, which can capture the hydraulic jump of dam-break flows. The comparison between the obtained numerical results and the experimental data of Miller and Chaudry in a semicircle channel shows the validity of the present numerical scheme. The mathematical model and the numerical method were applied to the dam-break flows in channels with various curvatures. Based on the numerical results, the influence of river curvatures on the dam-break flows was analyzed in details.

关键词： dam-break flow shallow-water equations,channel bend curvilinear coordinate Godunov-type finite-difference scheme

Effect of compressive stress on the dispersion relation of the flexural–gravity waves in a two-layer fluid with a uniform current

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Journal of Hydrodynamics 2014年第2期26卷 339-341页

作者：卢东强 Shanghai Institute of Applied Mathematics and Mechanics Shanghai University Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai University Computational Marine Mechanics Laboratory Department of Mechanical Engineering University of California

The explicitly analytical solution is derived for the dispersion relation of the flexural-gravity waves in a two-layer fluid with a uniform current. The upper＇ fluid is covered by a thin plate with the presence of the elastic, compressive and inertial forces. The density of each of the two immiscible layers is constant. The fluids of finite depth are assumed to be inviscid and incompressible and the motion be irrotational. A linear system is established within the framework of potential theory. A new representation for the dispersion relation of flexural-gravity waves in a two-layer fluid is derived. The critical value for the compressive force is analytically determined. The dispersion relation for the capillary-gravity with an inertial surface in a two-layer fluid can he obtained in parallel. Some known dispersion relations can be recovered from the present solution.

关键词： Hydroelasticity compressive force current two-layer fluid

AN OPTIMIZATION OF EIGENFUNCTION EXPANSION METHOD FOR THE INTERACTION OF WATER WAVES WITH AN ELASTIC PLATE

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Journal of Hydrodynamics 2009年第4期21卷 526-530页

作者： XU Feng lu dong-qiang Shanghai Institute of Applied Mathematics and Mechanics Shanghai University Shanghai 200072 China State Key Laboratory of Ocean Engineering Shanghai Jiao Tong University Shanghai 200030 China

The hydroelastic interaction of an incident wave with a semi-infinite horizontal elastic plate floating on a homogenous fluid of finite depth is analyzed using the eigenfunction expansion method. The fluid is assumed to be inviscid and incompressible and the wave amplitudes are assumed to be small. A two-dimensional problem is formulated within the framework of linear potential theory. The fluid domain is divided into two regions, namely an open water region and a plate-covered region. In this paper, the orthogonality property of eigenfunctions in the open water region is used to obtain the set of simultaneous equations for the expansion coefficients of the velocity potentials and the edge conditions are included as a part of the equation system. The results indicate that the thickness and the density of plate have almost no influence on the reflection and transmission coefficients. Numerical analysis shows that the method proposed here is effective and has higher convergence than the previous results.

关键词： wave scattering eigenfunction expansion method orthogonality

OVERVIEW OF THE 9TH INTERNATIONAL CONFERENCE ON HYDRODYNAMICS

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Journal of Hydrodynamics 2010年第5期22卷 742-744页

作者： lu dong-qiang Shanghai Institute of Applied Mathematics and Mechanics Shanghai University Shanghai 200072 China

The 9th International Conference on Hydrodynamics （ICHD）, held in Shanghai, China from 11 to 15 October, 2010, was briefly reviewed. More than 240 delegates from 23 countries and regions attended this Conference, at which three plenary lectures, two keynote lectures and more than 160 papers were delivered. A special symposium on hydrodynamics in honor of Prof. You-sheng He was jointly organized in this ICHD. The printed proceedings, edited by Y. S. Wu, S. Q. Dai, H. Liu et al. and published by China Ocean Press, collect 172 technical papers contributed from 26 countries and regions. The electronic proceedings are distributed by the Elsevier at the ScienceDirect website as ＂Journal of Hydrodynamics, 2010, Vol. 22, No. 5 （Supplement）＂.

关键词： countries International China Shanghai special keynote three Press two

OVERIVEW OF THE 6TH INTERNATIONAL CONFERENCE ON ASIAN AND PACIFIC COASTS

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Journal of Hydrodynamics 2012年第5期24卷 800-800页

作者： lu dong-qiang Shanghai Institute of Applied Mathematics and Mechanics Shanghai UniversityShanghai 200072China

The 6th International Conference on Asian and Pacific Coasts （APAC2011） was held in Hong Kong during December 14-16, 2011. This conference was jointly supported by the Chinese Ocean Engineering Society, the Coastal Engineering Committee of Japan Society of Civil Engineers, and the Korean Society of Coastal and Ocean Engineers, and was organized by Departments of Civil and Mechanical Engineering, The University of Hong Kong. More than 320 dele- gates from over 30 countries/regions, including China, Japan, Korea, Australia, Belgium, Demark, France, India, Indonesia, Italy, Netherlands, Russia, Singapore, UK, USA etc., attended the conference.

关键词： Mechanical Engineering Hong Kong Ocean Engineering

OVERVIEW OF THE 5TH INTERNATIONAL CONFERENCE ON ASIAN AND PACIFIC COASTS

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Journal of Hydrodynamics 2010年第1期22卷 146-146页

作者： lu dong-qiang Shanghai Institute of Applied Mathematics and Mechanics Shanghai University Shanghai 200072 China

The 5th International Conference on Asian and Pacific Coasts （APAC-2009） was held in the Nanyang Technological University （NTU）, Singapore from 13 to 16 October, 2009. This conference was jointly organized by the Chinese Ocean Engineering Society, the Coastal Engineering Committee of Japan Society of Civil Engineers, the Korean Society of Coastal and Ocean Engineers, and the Maritime Research Center at NTU. 227 delegates from 18 countries, including China, Japan, Korea, USA, The Netherlands, India, Indonesia, Singapore, Vietnam, UK, Afghanistan, Iran, etc., attended the conference.

关键词： Society Ocean Engineering International countries Research Chinese Center China

Boron-doped carbon dots:Doping strategies,performance effects,and applications

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Chinese Chemical Letters 2024年第7期35卷 100-106页

作者： qiang Fu Shouhong Sun Kangzhi lu Ning Li Zhanhua dong College of Engineering Qufu Normal UniversityRizhao 276826China

Due to their superior fluorescence,phosphorescence,and catalytic capabilities,carbon dots(CDs),an emerging class of fluorescent carbon nanomaterials,have a wide range of potential *** properties of CDs have recently been controlled extensively by heteroatom *** atoms have been effectively doped into the structure of CDs due to their similar size to carbon atoms and excellent electron-absorbing ability to further improve the performance of *** this review,we summarize the research progress of boron-doped CDs in recent years from the aspects of doping strategies,effects of boron doping on different performances of CDs and *** from the two aspects of single boron doping and boron and other atom co-doping,from different precursor materials to different synthesis methods,the doping strategies of boron-doped CDs are reviewed in ***,the effects of boron doping on the fluorescence,phosphorescence and catalytic performance of CDs and applications of boron-doped CDs in optical sensors,information encryption and anti-counterfeiting are ***,we further provide a prospect towards the future development of boron-doped CDs.

关键词： Carbon dots Boron-doped luminescent material Doping strategies Performance effects