水文土壤学理论及其应用研究进展

围绕水文土壤学的基本理论和核心科学问题,从地球关键区理论出发,介绍了水文土壤学的基本理论框架、水文土壤学所能填补的知识鸿沟,并回顾了水文土壤学在农业、流域管理、面源污染、湿地保护和环境政策制定以及土壤传递函数等方面的应用,最后对水文土壤学的发展和应用做了展望。     

波浪在水流作用下的变形

本文通过实验研究，分别观测了规则、波单向不规则波和多向不规则波在不同流速条件下的情况，同进利用静水中的实测波浪资料通过理论计算，分析了在水流中的波浪，并将计算值与实测值做了对比。比较表明，当波浪主方向与水流、法线方向的夹角不过大时，计算与实验吻合较好，表明所推荐的理论方法是可行的。     

FIVE MODE INTERACTIONS IN A FREE SHEAR LAYER

This study condiders spatially developing free shear layers at moderateReynolds numbers that are formed by the merging of two free streams initially separatedby a splitter plate.To study the nonlinear interactions between the two-and three-dimen-sional fundamental and subharmonic modes in the spatially developing shear layer,the se-lected five modes represent the minimum number that needs to be considered.The objec-tive of this study is to investigate the nonlinear effects arising from the interactions be-tween two-and three-dimensional large-scale coherent structures in a free shear layer.Our attention is focused on the energy exchange mechanisms between the various modes,and the effects of the nonlinear evolution of the phases of the interacting modes.It isshown that depending on the initial modal phase angles the downstream growth of theshear layer and the associated local entrainment can be strongly affected by the presence ofthese nonlinear interactions.This high sensitivity of the shear layer growt     

NONLINEAR DIFFRACTION FORCES ON LARGE MULTICYLINDRICAL OFFSHORE STRUCTURES

ＮＯＮＬＩＮＥＡＲ　ＤＩＦＦＲＡＣＴＩＯＮ　ＦＯＲＣＥＳ　ＯＮ　ＬＡＲＧＥ　ＭＵＬＴＩＣＹＬＩＮＤＲＩＣＡＬ　ＯＦＦＳＨＯＲＥ　ＳＴＲＵＣＴＵＲＥＳＮＯＮＬＩＮＥＡＲＤＩＦＦＲＡＣＴＩＯＮＦＯＲＣＥＳＯＮＬＡＲＧＥＭＵＬＴＩＣＹＬＩＮＤＲＩＣＡＬＯＦ...     

Optimising a Probabilistic Model of the Development of Play in Soccer

We present a probabilistic model based on the one developed by Hernández Mendo and Anguera (Revista de Psicologíca Social, 16(1), 71–93, 2001). Here we have tried to break down the interaction contexts that the opposing teams are able to generate and transform during the game. We are aware that a given player or team does not produce consistent behaviour in similar situations. However, a degree of uncertainty is assumed to exist regarding whether the results obtained are a specific function of the analysis used. In order to carry out this research a category system which optimized that used in the previous model was developed. This system should enable the interaction between teams to be observed within the actual play of a soccer game. A lag sequential analysis was performed on the basis of a coding of the behavioural flow. After describing the behavioural patterns obtained a probabilistic model of the development of play in soccer is proposed.     

振动边界耦合作用下基于微分求积法的三维不可压缩粘性流体的数值模拟

本文采用微分求积(DQ)法基于非交错网格建立在考虑流体-结构相互作用下求解三维不可压缩流体NavierStokes方程的数值方法。弹性振动边界为矩形薄板,诱发板振动的因素为作用在板上的脉动压力场,边界板的振动与流动形成耦合作用。数值结果给出了一箱形流道内雷诺数分别为100,1000和10000时的流场。大量分析表明．用本文方法模拟考虑流体一结构相互作用下的流动问题是可行的。     

南水北调中线北京段输水系统数字三维视景仿真

为直观形象的展示南水北调中线北京段输水系统，运用视景仿真技术，建立了包括北京段管涵、水工建筑物和周围景观在内的数字三维虚拟场景，并实现了整个系统的虚拟漫游。     

水能资源系统与生态系统互动关系的理论分析

在对水能资源系统与生态系统相互关系分析的基础上,分别从生态系统角度、水能资源系统角度提出了水能资源系统与生态系统互动关系的表现层面。从生态系统角度来看,生态系统对水能资源系统起到要素限定、功能保障、价值引导、生态约束等效应;从水能资源系统来看,水能资源的开发对生态系统起到景观改造、空间阻隔、效应干扰效应。以这些功能和效应为基础,水能资源与生态系统的协调应从要素层面、功能层面、效应层面及价值层面进行,综合协调体系的构建是提高二者协调度的重要保障。     

A semi-analytical solution for characteristics of a dam-reservoir system with absorptive reservoir bottom

In this study, a semi-analytical formulation based on the Scaled Boundary Finite Element Method （SBFEM） was proposed and used to obtain the solution for the characteristics of a two-dimensional dam-reservoir system with absorptive reservoir bottom in the frequency domain. For simplicity, the dam with arbitrary upstream faces was assumed to be rigid and was subjected to a horizontal ground acceleration, while the reservoir with absorptive bottom was assumed to be semi-infinite. The reservoir was divided into two sub-domains： a near-field sub-domain and a far-field sub-domain. The near-field sub-domain with arbitrary geometry was modelled by the Finite Element Method （FEM）, while the effects of the far-field sub-domain which was assumed to be horizontal were described by a semi-analytical formation. The semi-analytical formulation involved the effect of absorptive reservoir bottom, as well as the radiation damping effect of a semi-infinite reservoir. A FEM/SBFEM coupling formulation was presented to solve dam-reservoir coupled problems. The accuracy and efficiency of the coupling formulation were demonstrated by computing some benchmark examples. Highly accurate results are produced even if the near-field sub-domain is very small.     

FINITE ELEMENT ANALYSIS OF A VERTICAL RECTANGULAR PLATE COUPLED WITH AN UNBOUNDED FLUID DOMAIN ON ONE SIDE USING A TRUNCATED FAR BOUNDARY

The dynamic pressure distribution on a rectangular plate attached to a rigid wall and supporting an infinitely large extent of fluid subjected to a harmonic ground excitation is evaluated in the time domain. Governing equations for the fluid domain are set considering the compressibility of the fluid with negligibly small change in density and a linearized free surface. A far boundary condition for the three-dimensional fluid domain is developed so that the far boundary is truncated at a closer proximity to the structure. The coupled problem is solved independently for the structure and the fluid domain by transferring the acceleration of the plate to the fluid and pressure of the fluid to the plate in sequence. Helmholtz equation for the three-dimensional fluid domain and Mindlin's theory for the two-dimensional plate are used for the solution of the interacting domains. Finite element technique is adopted for the solution of this problem with pressure as nodal variable for the fluid domain and displacement for the plate. The time dependent equations are solved in each of the interacting domain using Newmark-b method. The effectiveness of the technique is demonstrated and the influences of surface wave, exciting frequency and flexibility of the plate on dynamic pressure are investigated.