基于Aquifer Test的水文地质参数计算方法研究

根据抽水试验结果,常用人工求参的方法确定水文地质参数。人工求参方法计算结果较为可靠,但计算过程繁琐,并且结果因人而异,具有人为随意性。利用AquiferTest软件求参,计算方便快捷,与人工求参方法对比,具有计算精度较高,规范性好等优点。     

WATER TUNNEL EXPERIMENTAL INVESTIGATION ON THE DRAG REDUCTION CHARACTERISTICS OF THE TRAVELING WAVY WALL

Drag reduction experiment of the traveling wavy wall at high Reynolds number is conducted.A suit of traveling wavy wall device is developed.The drag forces of the traveling wavy wall with various wave speeds(c)are measured under different water speeds(U)in the K15 cavitation water tunnel and are compared with that of the flat plate.The results show that the mean drag force of the traveling wavy wall have decreased and then increased with oscillation frequency increasing at the same flow speed.Under different flow speeds,when traveling wave wall reached to the minimum of drag force,the corresponding the ratio of the wall motion phase speed c to flow speed U,c /U is slightly different.Within the parameters of the experiment,whenc /U reaches a certain value,the drag force of the traveling wavy wall can be less than that of the flat plate.The drag reduction can be up to 42%.Furthermore,as the value ofc /U increases,the traveling wavy wall can restrain the separation and improve the quality of flow field.     

Extreme value analysis of streamflow time series in Poyang Lake Basin, China

Extreme meteorological and hydrological events may cause major disasters and heavy social and economic losses.Therefore,more and more studies have focused on extreme hydro-meteorological events in various climates and geographic regions.Based on nearly 50 years of observed records of the Poyang Lake Basin,the occurrence and changing trends of extreme streamflow indices,including the annual maximum flow,annual peak-over-threshold flows,and low flows,were analyzed for ten hydrological stations.The results indicate that most annual maximum flows occurred from April to July,highly attributed to the Southeast Asian summer monsoons,whereas the annual minimum flows were concentrated between January and February.As for the low flow indices (the annual minimum flow,annual minimum 7-d flow,and annual minimum 30-d flow),a significant increasing trend was detected in most parts of the Poyang Lake Basin.The trends illustrate the potential effects of climate change and human activities on the hydrological cycle over the Poyang Lake Basin.     

大型抽水蓄能电站首机首次启动试验方式选择研究——水泵工况启动试验方式关注的主要技术问题

对大型抽水蓄能电站首机首次水泵工况启动试验方式关注的主要技术问题,重点研究了9个技术难点和特点问题,提出分析意见和风险性评估。     

基于概率模型的随机裂隙优势产状取值

随机裂隙是广泛存在于岩体中的一种规模较小的结构面,由于其发育的随机性,故其产状、规模等结构面性质难于确定。但是,大量研究表明,同一地区相同地质环境下发育的随机裂隙,其结构面性质存在一定的统计规律。利用建立概率模型的方法,对某花岗岩地区水电站左岸坝基随机裂隙组的优势产状取值进行了探讨。通过建立概率模型所绘制出的概率曲线进行研究发现,相对于简单的求样本的算数平均值,取概率曲线峰值点所对应的数值为一组裂隙最佳产状更为合理。     

浅谈水产品检测样品的质量控制

对于水产品检测机构而言,对于检测样品进行质量控制的重要意义不言而喻。本文就水产品检测样品质量控制的各个环节进行了综述,可作为机构之间交流的基础。     

流溪河水电厂1号机组上机架振动增大问题分析与处理

介绍了流溪河水电厂1号机组的历次处理情况。从机组轴线变化、下导瓦背抗顶块抗压强度、发电机转子动平衡试验等方面着手,通过机组大修和变转速实验,综合分析了1号机组上机架振动增大的原因。通过严格执行检修工艺和检修质量标准,彻底解决了1号机组上机架振动增大的问题。     

改进的灰色灾变模型在干旱预测中的应用

为提高传统的GM(1,1)模型精度,分别从原始数据序列检验和建立残差修正模型两方面进行了改进,并将改进的灰色灾变模型与不进行原始序列检验的GM(1,1)1模型和对原始数据序列进行检验的GM(1,1)2模型进行了比较。结果表明:改进的灰色灾变模型精度最高;运用该模型预测榆林市未来可能发生干旱的年份分别为2012年、2015年和2019年。     

设计洪水估计值的抽样误差分析与应用

在设计洪水估计值的抽样误差分析中,采用B值诺模图方法估计均方误差简单易用。文章对在水电工程中经常采用的P-Ⅲ型经验适线法估计的设计洪水成果如何借助优化适线法参数来估算设计洪水值的抽样误差进行了分析说明。不同的优化适线法会得到不同的诺模系数B,估算设计洪水估计值的抽样误差时,选用某一准则的优化适线要使用相应的诺模系数B值。并分别对实测洪水的连序系列及含历史洪水的不连序系列资料进行了应用分析。     

THE NATURAL CONVECTION OF AQUIFERS WITH CONSTANT HEAT SOURCES AND ITS INFLUENCE ON TEMPERATURE FIELDS

By combining sand tank tests with numerical simulations, this paper studies the temperature fields around constant heat sources to reveal the mechanism of the natural convection and its influence on the temperature fields in the process of energy storage. Using the "24-channel temperature auto acquisition system" developed by our research group in the tests, the temperatures are recorded at measuring points within the research area in the tests, the revised Brinkman equation and a transfer-convection balance model are used for solving the aquifer water-thermal coupling problems, and through comparison of the test results with the calcula- tion results, it is discovered that the influence ranges and the variations of the two temperature fields are consistent, which validates the mathematical model. On the basis of this, we also study the influences of the heat source positions and the boundary conditions on the temperature fields, and the results show that, under the natural convection, the heat source positions may influence the distri- bution of the temperature fields, thus affect the energy storage. For the same energy storage layer, the temperature field for the top energy storage is characterized by a smaller heat influence range and a relatively concentrated temperature distribution. However, when the heat source is at the bottom, the range of a temperature field, and the temperature is relatively dispersed, which is not favorable to heat recycle, with the same heat source position, the boundary conditions determine the size of the critical Rayleigh number, and thus have an influence on the occurrence and the strength of the natural convection, and accordingly, on the temperature fields.