三体船在斜浪规则波中运动响应预报方法研究

对于三体船在波浪中的水动力预报,航速效应和主体与片体间水动力干扰效应是水动力载荷合理预报的关键之处,需合理考虑.二维半势流理论可较为准确反映上述效应,已在三体船顶浪中垂向运动响应理论预报上获得了较为满意的结果.在此基础上,该文探讨了该方法在三体船斜浪中运动特别是横摇预报上的应用.为较准确获得三体船横摇运动时粘性阻尼贡献,采用三体船模静水中自由横摇衰减试验获得了自由横摇运动衰减曲线,并经能量法处理获得了船舶横摇阻尼系数.然后,结合二维半理论,获得了三体船运动数值解.数值解与斜浪规则波中运动响应模型试验结果符合较好,反映本文所采用的数值方法可较好地预测三体船斜浪中水动力载荷和运动,可用于三体船在波浪中耐波性评估.     

金沙江乌东德水库诱发地震统计预测研究

为了研究乌东德水库诱发地震的可能性,在选用国内外377座已建水库统计资料的基础上,对乌东德水库诱发地震进行预测分析。针对具体地质条件,共选出了10个影响因子,并将影响因子细化为3种不同状态,在此基础上建立了水库诱发地震预测统计模型。模型将诱震的10个概率因子表述为几个相应的地理位置可以完全叠加的矢量图层,然后进行GIS图层计算,实现了水库诱发地震的统计预测。研究结果表明,乌东德水库具备诱发地震的可能性。     

高清数字钻孔电视技术研发及其在水电工程中的应用

 钻孔电视是能直观获得钻孔孔壁原状图像的地球物理方法,高清数字钻孔电视技术采用了先进的时间定时器,改进了光学工艺,加入了人-机互动调色功能的高分辨率摄像头,应用了消除电磁场对图像影响的处理技术,使其具有高精度、高分辨率和高保真度等特点。在某水电站坝址和围堰深厚覆盖层可视化研究中,利用高清数字钻孔电视技术,可清晰地获得钻孔孔壁原状图像,从而有效地查明工区的地质情况,为顺利施工提供技术保障,并为建立“数字化电子岩芯库”奠定了坚实的基础。     

NUMERICAL STUDY OF NON-AQUEOUS PHASE LIQUID TRANSPORT IN A SINGLE FILLED FRACTURE BY LATTICE BOLTZMANN METHOD

In this article,the Non-Aqueous Phase Liquid(NAPL)transport in the single filled fracture was studied with the Shan-Chen multi-component multiphase Lattice Boltzmann Method(LBM)with special consideration of wettability effects.With the help of the model,the contact angle of the non-wetting phase and wetting phase interface at a solid wall could be adjusted.By considering a set of appropriate boundary conditions,the fractured conductivity was investigated in condition that the NAPL blocks the channels in the single filled fracture.In order to study the wettability effects on the NAPL transport,a constant driving force was introduced in the Shan-Chen multi-component multiphase LBM.Flow regimes with different wettabilities were discussed.Simulated results show that the LBM is a very instrumental method for simulating and studying the immiscible multiphase flow problems in single filled fracture.     

基于RBF多变量时间序列的滑坡位移预测研究

斜坡是一个受到多种因素影响的混沌动力系统,斜坡位移是其内部力学现象的宏观表现,具有很强的不确定性,从而导致难以建立斜坡位移的确定性方程。滑坡是斜坡的一种成因类型,具有相同的系统特性。滑坡经过防治后,其位移的主要外在动力因素除地下水外同时还受到防治设施的控制。滑坡位移及其影响因素所构成的混沌时间序列能够反映滑坡位移动力系统的历史行为。根据观测获得的多变量时间序列重构原滑坡位移动力系统,采用RBF神经网络实现变量间的映射关系,对滑坡位移进行了预测。预测结果对比分析表明:采用多变量时间序列预测模型能对滑坡位移进行有效预测,取得比单变量时间序列预测模型更好的预测效果;多变量时间序列预测模型具有更明确的物理力学意义,更能反映滑坡演化变形的实质特征。     

利用GM（1,1）模型对地下水恢复进行预测分析

沧州市区关停深层自备井后,深层地下水恢复取得了明显的效果。本文采用色系统中GM（1,1）模型对第Ⅴ含水组地下水埋深进行预测。     

基于自由搜索的水库入库含沙量预测模型

水库泥沙淤积问题直接关系到水库的规模、寿命以及综合经济效益的发挥。入库水流含沙量是影响水库调度运行以及水库泥沙淤积的主要因素,目前国内结构简单、实用性较强的含沙量预测模型不多。以水库的入库站流量及上游站至入库站的区间流量为研究对象,提出了基于两个水文站流量的水库入库含沙量的预测模型,采用改进的自由搜索算法率定模型参数,并将模型应用于龚嘴水库的入库含沙量的预测。研究结果表明,构建的模型结构简单,参数率定便捷,预测含沙量的精度较高,为水库入库含沙量预测提供了一种简便适用的方法。     

气象集合预报的研究进展

集合预报是数值预报发展的一个重要方向,相对于单一的确定性预报,它考虑了初值及模式的不确定性,其结果反映了未来天气的多种状况,能为用户提供确定性预报所不能提供的信息(如预报结果的可信度等)。降水信息是水文预报系统的核心输入,单一的降水预报存在着不确定性,从而使得水文预报也存在不确定性。这种不确定性制约了水利工程调度的科学性。集合预报在一定程度上能解决这种不确定性。从而在水文领域,气象集合预报具有较高的应用价值。为了水文工作者能够更好地应用集合预报,本文首先基于系统的角度,对集合预报系统中的初值扰动、模式扰动和集合预报产品等研究现状及成果进行了评述,然后分析了降水集合预报产品在水文预报领域中的应用情况,最后对集合预报在水文领域中的应用进行了展望。     

Development and validation of a biodynamic model for predicting multi-finger movements in cylinder-grasping tasks †

This article describes the development and validation of a model for predicting multi-finger movements in grasping activities. The model builds upon a newly proposed approach that incorporates forward dynamics and a system identification procedure, and is amenable to empirical tests. A database of multi-fingered grasping movements performed by 28 subjects was established and divided into four sets, one for model development and three for model validation. In the development phase, model parameter values were estimated by the iterative system identification procedure through a physics-based heuristic algorithm. The estimated parameter values were then statistically synthesised and integrated into the prediction model. In the validation phase, the model was applied to three novel datasets containing different grasping movements involving objects of varied sizes and different subjects. The results demonstrated the model's ability to predict hand prehensile movements with error magnitudes comparable to the inter-person variability in performing such movements. New insights into the control of multi-fingered hand prehensile movements at the systems and joint levels emerged from the model development and validation process. The current study contributes to building a foundation for long-term development of realistic biodynamic simulation of multi-finger hand movements. Such simulation capabilities will aid in design of hand-operated tools, devices or hand-intensive work for proactive ergonomics and in evaluation as well as treatment of functional impairment of the hand.     

A novel method for predicting breakthrough time of horizontal wells in bottom water reservoirs

Dimensional analysis and numerical simulations were carried out to research prediction method of breakthrough time of horizontal wells in bottom water reservoir. Four dimensionless independent variables and dimensionless time were derived from 10 influencing factors of the problem by using dimensional analysis. Simulations of horizontal well in reservoir with bottom water were run to find the prediction correlation. A general and concise functional relationship for predicting breakthrough time was established based on simulation results and theoretical analysis. The breakthrough time of one conceptual model predicted by the correlation is very close to the result by Eclipse with less than 2% error. The practical breakthrough time of one well in Helder oilfield is 10 d, and the predicted results by the method is 11.2 d, which is more accurate than the analytical result. Case study indicates that the method could predict breakthrough time of horizontal well under different reservoir conditions accurately. For its university and ease of use, the method is suitable for quick prediction of breakthrough time.