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Acoustic scattering from fluid-filled finite cylindrical shell in water:Ⅱ.Experiment

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Chinese Journal of Acoustics 2011年第3期30卷 301-312页

作者： ZHENG Guoyin FAN Jun TANG Weilin state key Laboratorg of ocean engineering Shanghai Jiao Tong University Shanghai 200240

Acoustic scattering from the submerged fluid-filled finite cylindrical shell insonified by an incident plane wave is studied experimentally and theoretically. A monostic broadband transducer with the sharp directivity is used in the experiment. The broadband LFM signal and the single-frequency narrow pulse are used to measure the backscattering field of the cylindrical shell. The measured results have a good agreement with the theory both in time and frequency domain. The theoretical and experimental results show that the resonances of several additional waves which are caused by the internal fluid are presented in the frequency domain. And a series of ＇whispering gallery＇ waves produced by the waves reflected back and forth in the internal fluid filled in the cylindrical shell are added. The reason for the clustering of the bowl-shape resonance curves in the frequency-angle spectrum is explained as the superposition of the first several modes of ＇whispering gallery＇ waves.

关键词：散射实验圆柱壳液体声散射宽带换能器共振频率入射平面波 LFM信号

Hydroelastic interaction between water waves and a thin elastic plate of arbitrary geometry

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Science China(Physics,Mechanics & Astronomy) 2011年第1期54卷 59-66页

作者： XU Feng LU DongQiang Shanghai Institute of Applied Mathematics and Mechanics Shanghai University Shanghai 200072 China Shanghai key laboratory of Mechanics in Energy engineering Shanghai 200072 China

An analytical method is developed for the hydroelastic interaction between surface incident waves and a thin elastic plate of arbitrary geometry floating on an inviscid fluid of finite depth in the framework of linear potential *** kinds of edge conditions are considered and the corresponding analytical representations are derived in the polar coordinate *** to the surface boundary conditions,the fluid domain is divided into two regions,namely,an open water region and a plate-covered *** the assumption that all the motion is time-harmonic,the series solutions for the spatial velocity potentials are derived by the method of eigenfunction *** matching conditions for the continuities of the velocity and pressure are transformed by taking the inner products successively with respect to the vertical eigenfunction for the free surface and the angular eigenfunction.A system of simultaneous equations,including two edge conditions and two matching conditions,is set up for deriving the expansion *** an example,numerical computation for the expansion coefficients of truncated series is performed for an elliptic *** results show that the method suggested here is useful to revealing the physical features of the gravity wave scattering in the open water and the hydroelastic response in the plate.

关键词： wave scattering method of matched eigenfunction expansions elastic plate arbitrary geometry hydroelastic response

Global buckling behavior of submarine unburied pipelines under thermal stress

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Journal of Central South University 2013年第7期20卷 2054-2065页

作者：郭林坪刘润闫澍旺 state key laboratory of Hydraulic engineering Simulation and Safety (Tianjin University)

Buckling of submarine pipelines under thermal stress is one of the most important problems to be considered in pipeline design. And pipeline with initial imperfections will easily undergo failure due to global buckling under thermal stress and internal pressure. Therefore, it is vitally important to study the global buckling of the submarine pipeline with initial imperfections. On the basis of the characteristics of the initial imperfections, the global lateral buckling of submarine pipelines was analyzed. Based on the deduced analytical solutions for the global lateral buckling, effects of temperature difference and properties of foundation soil on pipeline buckling were analyzed. The results show that the snap buckling is predominantly governed by the amplitude value of initial imperfection; the triggering temperature difference of Mode I for pipelines with initial imperfections is higher than that of Mode I1; a pipeline with a larger friction coefficient is safer than that with a smaller one; pipelines with larger initial imperfections are safer than those with smaller ones.

关键词： submarine pipeline lateral buckling analytical solution initial imperfection subsoil friction resistance

Distribution of polybrominated diphenyl ethers in the surface sediment of the East China Sea

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Chinese Science Bulletin 2014年第4期59卷 379-387页

作者： Huijuan Li Jing Lan Guoliang Li Zongshan Zhao Guibin Jiang key laboratory of Marine Chemistry Theory and Technology Ministry of Education Ocean University of China College of Chemistry and Pharmaceutical Sciences Qingdao Agricultural University state key laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental Sciences Chinese Academy of Sciences

The concentrations of polybrominated diphenyl ethers(PBDEs)were determined in the surface sediments of 20 locations in the East China Sea(ECS).The P PBDEs(sum of 13 PBDE congeners,without brominated diphenyl ether 209(BDE209)ranged from 2.6 to 49 pg g-1(dry weight)with an average of 21 pg g-1,which fell at the low end of the global *** spatial distribution presented an offshore decreasing trend towards the outer shelf and along the coastline,suggesting a direct influence of the inputs by the Yangtze *** P PBDE concentrations were influenced by the total organic carbon of the sediment,as demonstrated by their similar spatial *** P C27?C29?C31n-alkanes concentrations and sand%reported in the literature for sediments in the ECS presented similar spatial distributions as P PBDEs,which suggests that a considerable part of P PBDEs may come from the Yangtze River and that grain size plays an important role in PBDE *** three dominant congeners were BDE28(19.8%),BDE47(26.4%),and BDE99(16.8%).The present study compared the congener patterns of the sedimentary PBDEs with those of commercial *** results indicated the possible use of penta-BDE in the Yangtze River Basin in a wide range or the fractionation and transformation of PBDE congeners during their long-range transport.

关键词：多溴联苯醚沉积物分布表层沉积物东中国海多溴二苯醚空间分布长江流域 PBDEs

Flexural-gravity wave resistances due to a surface-moving line source on a fluid covered by a thin elastic plate

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Theoretical & Applied Mechanics Letters 2013年第2期3卷 68-71页

作者： D.Q.Lu H.Zhang Shanghai Institute of Applied Mathematics and Mechanics Shanghai University Shanghai key laboratory of Mechanics in Energy engineering Shanghai University

Analytical solutions for the flexural-gravity wave resistances due to a line source steadily moving on the surface of an infinitely deep fluid are investigated within the framework of the linear po- tential theory. The homogenous fluid, covered by a thin elastic plate, is assumed to be incompressible and inviscid, and the motion to be irrotational. The solution in integral form for the wave resistance is obtained by means of the Fourier transform and the explicitly analytical solutions are derived with the aid of the residue theorem. The dispersion relation shows that there is a minimal phase speed cmin, a threshold for the existence of the wave resistance. No wave is generated when the moving speed of the source V is less than emin while the wave resistances firstly increase to their peak values and then decrease when V ~〉 Crnin. The effects of the flexural rigidity and the inertia of the plate are studied. @ 2013 The Chinese Society of Theoretical and Applied Mechanics. [doi：10.1063/2.1302202]

关键词： wave resistance hydroelasticity flexural rigidity inertia

Acoustic scattering from a fluid-filled finite cylindrical shell in water:Ⅰ.Theory

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Chinese Journal of Acoustics 2011年第3期30卷 288-300页

作者： ZHENG Guoyin FAN Jun TANG Weilin state key laboratory of ocean engineering Shanghai Jiao Tong University Shanghai 200240

Acoustic scattering from a submerged fluid-filled finite cylindrical shell insonified by an incident plane wave was studied. The analytic solutions of the scattering field are derived using the elastic thin shell theory with the boundary conditions. The fluid-filled impedance, due to the effect of internal fluid, must add to the impedance of the system. The results show that in the backscattering field, rigid scattering has a large contribution only on the broadside and elastic scattering play a major role when oblique incidence. The dispersion curves of the phase velocity show that comparing with the internal vacuum condition, except the contribution by longitudinal wave and shear wave near the broadside a series of the additional waves caused by the internal fluid is added which have great contribution to the scattering field. Bowl- shape resonance curves are presented in the frequency-angle spectrum as the contribution of the internal fluid waves.

关键词：声散射圆柱壳液体水下弹性薄壳理论入射平面波散射场边界条件

Finite element analysis on thermal upheaval buckling of submarine burial pipelines with initial imperfection

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Journal of Central South University 2013年第1期20卷 236-245页

作者：刘润王武刚闫澍旺 state key laboratory of Hydraulic engineering Simulation and Safety (Tianjin University)

In-service hydrocarbons must be transported at high temperature and high pressure to ease the flow and prevent the solidification of the wax fraction. The pipeline containing hot oil will expand longitudinally due to the rise in temperature. If such expansion is resisted, for example by frictional effects over a kilometer or so of pipeline, compressive axial stress will be built up in the pipe-wall. The compressive forces are often so large that they induce vertical buckling of buffed pipelines, which can jeopardize the structural integrity of the pipeline. A typical initial imperfection named continuous support mode of submarine pipeline was studied. Based on this type of initial imperfection, the analytical solution of vertical thermal buckling was introduced and an elastic-plasticity finite element analysis （FEA） was developed. Both the analytical and the finite element methodology were applied to analyze a practice in Bohai Gulf, China. The analyzing results show that upheaval buckling is most likely to build up from the initial imperfection of the pipeline and the buckling temperature depends on the amplitude of initial imperfection. With the same amplitude of initial imperfection, the triggering temperature difference of upheaval buckling increases with covered depth of the pipeline, the soil strength and the friction between the pipeline and subsoil.

关键词： submarine buried pipeline thermal stress upheaval buckling finite element method

Global lateral buckling analysis of idealized subsea pipelines

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Journal of Central South University 2014年第1期21卷 416-427页

作者：刘润刘文彬吴新利闫澍旺 state key laboratory of Hydraulic engineering Simulation and Safety(Tianjin University) School of engineering Design Pennsylvania State UniversityUniversity Park

In order to avoid the curing effects of paraffin on the transport process and reduce the transport difficulty,usually high temperature and high pressure are used in the transportation of oil and *** differences of temperature and pressure cause additional stress along the pipeline,due to the constraint of the foundation soil,the additional stress can not release freely,when the additional stress is large enough to motivate the submarine pipelines *** this work,the energy method is introduced to deduce the analytical solution which is suitable for the global buckling modes of idealized subsea pipeline and analyze the relationship between the critical buckling temperature,buckling length and amplitude under different high-order global lateral buckling *** obtain a consistent formulation of the problem,the principles of virtual displacements and the variation calculus for variable matching points are *** finite element method based on elasto-plastic theory is used to simulate the lateral global buckling of the pipelines under high temperature and *** factors influencing the lateral buckling of pipelines are further *** upon some actual engineering projects,the finite element results are compared with the analytical ones,and then the influence of thermal stress,the section rigidity of pipeline,the soil properties and the trigging force to the high order lateral buckling are *** method of applying the small trigging force on pipeline is reliable in global buckling numerical *** practice,increasing the section rigidity of a pipeline is an effective measure to improve the ability to resist the global buckling.

关键词： pipeline high order lateral buckling analytical solution finite element analysis influence factors

嵌入粘弹性包覆层的吸声覆盖层低频性能研究(英文)

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船舶力学 2009年第6期13卷 1022-1032页

作者：陶猛汤渭霖范军上海交通大学机械系统与振动国家重点实验室上海200240 上海交通大学船舶海洋与建筑工程学院上海200240

在单层粘弹性圆柱管吸声覆盖层的基础上,发展了嵌入低剪切波波速包覆层即双层粘弹性圆柱管的吸声结构的理论模型。推导了轴对称波特征方程的低频近似解,并根据牛顿迭代法进一步计算精确解,为吸声覆盖层的低频性能快速预报提供基础。数... 详细信息

在单层粘弹性圆柱管吸声覆盖层的基础上,发展了嵌入低剪切波波速包覆层即双层粘弹性圆柱管的吸声结构的理论模型。推导了轴对称波特征方程的低频近似解,并根据牛顿迭代法进一步计算精确解,为吸声覆盖层的低频性能快速预报提供基础。数值分析表明包覆层嵌入比例的增加、或者包覆材料剪切波速的减小能有效地改善低频吸声性能。

关键词：粘弹性包覆层低频近似牛顿迭代法吸声系数