基于SPH-FE方法的波浪中结构物动力特性模拟研究

海工结构物在波浪荷载作用下产生动力响应,本文基于光滑粒子流体动力学-有限元(SPH-FE)耦合方法对结构物受孤立波冲击过程中表面压力分布和动力响应特性进行研究.通过溃坝模型模拟了水柱倒塌冲击结构物的过程,分析SPH模型中粒子间距对数值结果的影响,并通过与文献结果对比验证了本文数值方法的可行性.在此基础上研究水柱高度、水柱与结构物间距及结构物刚度对波浪到达时间、结构动力响应和波浪冲击荷载特性的影响.研究结果表明:在本文计算条件下,波浪到达结构物的时间与溃坝初始水柱高度关系不明显,但随水柱与结构物间距的增大而线性增加;结构物顶端位移响应幅值随水柱高度、水柱与结构物间距及结构物刚度的变化较明显;结构物所受波浪冲击荷载与水动力作用呈正相关关系;当水动力作用相同,结构刚度增大时,结构物底端所受波浪力会增大.     

三维数值波浪水池技术与应用

建立了用于波浪-结构物相互作用数值模拟的三维数值波浪水池．应用VOF方法对粘性流动的基本方程进行数值求解并描述其自由表面，水池计算域的一侧使用数值造波机条件产生斜入射波浪，其下游开边界联合使用辐射条件和局部强迫衰减，侧向边界使用周期性条件使斜向波浪透过．数值试验表明，所建立的三维数值波浪水池产生和传播波浪具有良好的重复性和稳定性，应用于海洋结构物波浪荷载的确定也是可靠的．     

二层海洋中波浪对透空双圆柱的绕射作用分析

结构表面布孔可以减弱波浪载荷,而海水的层化将导致表面波和内波的二重绕射作用机制。对此,本文分析并计算了在二层海洋条件下大直径透空双圆柱的水波绕射作用,并分别与均匀海中透空和非透空双柱的相应结果加以比较。计算结果表明,在层化海洋中结构物的透孔性对减弱波浪力有一定影响,密度比变化对内波波浪力影响显著。     

波浪中浮体运动与遭遇荷载计算研究

给出随机波浪运动要素及其作用下流场的分析方法和海洋结构物的运动与遭遇荷载的计算方法．关于我国沿海设计波参数的预报、非线性波流场的计算、修正的切片法和三维浮体运动与荷载的面元计算法的研究成果及其相应的计算机程序,已经部分地得到了试验和相关研究成果的验证,并获得了船舶与海洋结构物设计工程的应用．     

畸形波作用下海洋平台小尺度杆件波浪荷载分析

为准确计算复合结构中小尺度杆件上的波浪荷载,不仅要考虑入射波浪作用,还应该考虑大尺度结构物对波浪的绕射以及辐射影响.以畸形波对固定圆柱作用产生的绕射场为例,用Morison公式计算绕射场作用下细小杆件的波浪荷载.用高阶边界元法建立波浪对结构物作用的时域计算程序,利用积分方程求域内水质点由绕射势产生的速度和加速度.结果显示,在一定波浪条件下,杆件上的总波浪力为入射波浪力的1.2倍.因此,在工程中应充分考虑复合结构中由于大尺度结构物存在产生的绕射和辐射作用对细小杆件的波浪力.     

大尺度结构物附近小尺度杆件上波浪力的时域分析

为准确计算复合结构中小尺度杆件上的波浪荷载,不仅需考虑入射波浪的作用,还应该考虑大尺度结构物对波浪的绕射以及辐射的影响.本文以波浪对固定圆柱作用产生的绕射场为例,用Morison公式计算绕射场作用下细小杆件的波浪荷载.用高阶边界元法建立波浪对结构物作用的时域计算程序,利用积分方程求解域内水质点由绕射势产生的速度和加速度.结果显示,在一定的波浪条件下,考虑绕射波浪力得到的总力可达到入射波浪力的2倍.因此,在工程中应充分考虑复合结构中由于大尺度结构物存在而产生的绕射和辐射作用于细小杆件的波浪力.     

波浪作用下结构的动力响应研究

波浪力是作用在港口工程结构物上的主要荷载之一,由于波浪的特性,结构物在波浪作用下会产生振动、疲劳等危害。利用有限元软件ANSYS模拟墩台结构,计算分析了该结构在波浪荷载作用下的内力、位移和振动等动力响应问题。计算由四个部分组成:重力作用下的结构静力响应、结构模态分析、结构谐响应分析和波浪作用下结构瞬态动力分析。     

不规则波对透空式建筑物上部结构冲击作用时域分析

对透空式建筑物上部结构的不规则波冲击作用进行了试验研究．试验靶谱是JONSWAP谱，试验中选取的入射波波高H1/3的范围为0．10～0．25m，谱峰周期Tp的范围为1．0～2．0s，结构物底面距静水面的高度s与入射波高H1/3之比的范围为-0．1～0．4．给出了不同试验组次的结构物底面所受波浪冲击压力的统计分析结果，得出结构物底面所受波浪冲击压力的特征值沿结构物底面分布特性．s／H1/3对作用于结构物底面的冲击压力峰值有很大影响，冲击压力峰值最大值出现在s／H1/3=0．1～0．2．     

作用于二层海洋中大直径透空圆环墩柱上的波浪渗流力*

基于Biot渗流固结理论与层化海绕射波理论,应用特征函数展开法,研究了二层海洋中立于可渗弹性海床上透空圆环墩柱的波浪渗流力问题,给出了表面波和内波所致波浪渗流压力场的解析解式,由此计算了作用于固立透空圆环墩柱底部上由波浪渗流压力所导致的浮托力和倾覆力矩。计算结果表明圆环柱外表面的透空性对表面波和内波的波浪直接作用具有明显的减弱效应,而对波浪渗流倾覆力矩也具有一定的减弱效应。内波所致波浪渗流倾覆力矩可能超过表面波对应的作用。圆环墩柱内外柱半径比减小对波浪力矩的减弱效应较渗流倾覆力矩更为明显。     

波浪对弹性支撑结构物冲击作用试验研究

位于浪溅区的弹性结构物的上部结构可能会受到幅值很大、历时较短的波浪冲击荷载.高强度的瞬时冲击荷载作用以及由它引起的结构振动响应往往是导致结构损坏的主要原因.通过物理模型试验,研究了波浪对弹性支撑平板结构的冲击作用.试验中设计了3种不同支撑刚度的结构物模型,对结构物底面所受的波浪冲击压力和结构物振动加速度响应进行了同步观测.分析了支撑刚度对冲击压力和结构振动的影响,以及结构物所受的波浪冲击压力与对应时段振动加速度之间的关系.试验结果表明,结构物支撑刚度越大,其所受的冲击压力也越大,对应时段的振动加速度幅值也越大.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that