共查询到20条相似文献，搜索用时 625 毫秒
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深入分析横断面流速分布特性,提出横断面垂线平均流速分布模型及计算公式。该模型利用大断面、河道水位及断面上一条垂线的平均流速,即可较准确地计算出断面上任意一条垂线的平均流速,从而计算出断面流量。这种方法缩短了测流历时,在保证测流精度的同时,为防汛调度决策延长了预见期。讨论了该方法的应用条件、误差来源和误差控制方法。为明渠实时在线监测提供了一种新的方法,为明渠流量计研发奠定了理论基础。 相似文献
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H-ADCP流量在线监测指标流速法定线软件"定线通"介绍与应用 总被引：2，自引：0，他引：2
为适应H-ADCP应用于大江大河流量在线监测的需要,专门开发了指标流速法定线软件"定线通"."定线通"内置五种形式的回归方程(即断面平均流速与指标流速之间的函数关系).只需输入实测流量、H-ADCP指标流速、水位、及大断面数据,"定线通"便可以对五种回归方程进行回归分析,即刻给出回归系数、定线评估参数和图形、及定线报告."定线通"界面友好、使用方便.为应用H-ADCP进行流量在线监测提供了有效的定线工具. 相似文献
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主流平均流速法是通过实测主槽部分断面面积的主流区内3－5条垂线流速，计算出断面流量的一种测验方法，该方法的实施可有效缩短测流历时，能够完全整地控制洪水过程呼水位流量关系的转折变化。以具有代表性的范围口水文站为例，探讨了主流平均流速法在黄河下游宽浅河道断面洪水测验中应用的可行性。 相似文献
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对声学多普勒流速剖面仪在实际应用中进行了分析.通过在白山水库采用走航式及定点测流(垂向代表线法)两种方式,对白山水库测流断面进行了流量测验、流速分布及流向测量.声学多普勒流速剖面仪既适用于自由水面又适用于封冻期测量,最后对声学多普勒流速剖面仪进行了讨论. 相似文献
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内陆河流域河流水面流速系数比测试验研究 总被引：1，自引：0，他引：1
水面流速系数是流量测验中经常使用的参数.目前,大部分水文站使用水面流速系数均选用经验值,为提高流量洲验精度,2003-2007年间.在内陆河流域代表站莺落峡、高崖、正义峡、祁连、肃南水文站开展了对水面流速系数的比测试验工作,取得大量比测试验资料.通过分析得出试验分析成果,并对试验分析计算方法和比测试验方法进行了探讨.水面流速系数分析计算方法采用算术平均法、回归分析法.两种分析方法得出的结论基本一致.算术平均法是对回归分析成果的校核.因此均采用回归分析法比测试验分析成果.以莺落峡站为例对垂线比测法和断面流量比测法两种不同比测试验方法进行对比分析和比测试验方法优选.垂线比测法和断面流量比测法均能得到比较满意的结果,相关系数均达O.95以上,分析成果比较接近.断面流量比测法理论比较严密,得到的水面流速系数适合全断面应用.这些试验分析成果为提高流量测验精度提供理论依据. 相似文献
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一、水电站泄流与非恒定流1.水电站机组起动与停机都很迅速,因而其泄流过程变化很大,并导致尾水河道的水位、过水断面和流速等在瞬时内速变,这种水力要素随时间变化的河渠水流属明渠非恒定流。当水电站机组开机时,闸门突然开启,流量骤增,在尾水河道引起的波体,其传播方向与水流方向相同,且水位上升,这种波称为顺涨波;当水电站机组停机时,闸门突然关闭, 相似文献
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目前,测流不确定度通过误差试验或通过经验数值来确定,但这些方式存在着工作量大或不确定估计不足等局限性。为解决此问题,对基于实测数据和统计理论的插值方差估计法在不同测流条件下进行了验证,选取白河、襄阳和沙洋3个流量站进行了实测数据的不确定度分析,同时对白河站进行了Monte Carlo试验,比较插值方差估计法得到的不确定度与真实误差的差异。结果表明,插值方差估计法能较好地反映水位变化的影响,插值方差估计法所得到的不确定度与真实测流误差的相关系数达0.64,与断面水位变化的Spearman相关系数达0.79,高、中水位情况下插值方差估计法的不确定度估计结果较为合理,低水位情况下偏高。 相似文献
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Tai Ho Choo Soo Kwon Chae Hyeon Cheol Yoon Yeon Moon Choo 《Environmental Earth Sciences》2014,71(2):675-683
Discharge is an important factor in river design for water utilization, water control and hydraulic structures; therefore, an accurate estimation of the discharge is required. At present, a rating curve depicting the relationship between a stage and discharge is used to calculate the discharge from river systems. Although the rating curve has an advantage in that it can predict and use the discharge during the flood season in which the measurement is difficult, there is room for improvement as it does not reflect the hydraulic characteristics of rivers. Therefore, in this study, discharge was predicted using the convenient calculation method with empirical mediating variables of the Manning and Chezy equations which were proposed by the author’s previous research as a new methodology for estimating discharge in an open channel. This was proven, based on the data measured in a meandering open channel system in a lab at the Mississippi River in the US and at the Columbia Del Dique Canal, and an accuracy level at a coefficient of 0.8 was demonstrated. Thus, this method, which reflects the hydraulic characteristics and predicts the discharge in a simple manner, is expected to be convenient in practice. 相似文献
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In this paper, a new type of large soil triaxial machine in detailed. The instrument which is composed of machine measurement and electrical measurement and automatic measurement with microcomputer, has the following functions: automatic monitor, control, analysis, printing and plotting. This paper also principally introduces the design method of software and hardware, working principle and its application example, that Fushung Branch of Coal Academia Sinica used this instrument to study stability of slope of an open pit, and bad gained satisfactory results. 相似文献
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In this paper, we present a method for attenuating background random noise and enhancing resolution of seismic data, which takes advantage of semi-automatic training of feed forward back propagation (FFBP) artificial neural network (ANN) in a multiscale domain obtained from wavelet packet analysis (WPA). The images of approximations and details of the input seismic sections are calculated and utilized to train neural network to model coherent events by an automatic algorithm. After the modeling of coherent events, the remainder data are assumed to be related to background random noise. The proposed method is applied on both synthetic and real seismic data. The results are compared with that of the adaptive Wiener filter (AWF) in synthetic shot gather and real common midpoint gather and also with that of band-pass filtering on real common offset gather. The comparison indicates substantially higher efficiency of the proposed method in attenuating random noise and enhancing seismic signals. 相似文献
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An estimation of discharge using mean velocity derived through Chiu’s velocity equation 总被引：1，自引：1，他引：0
To estimate discharge through the year (dry season and flood season), a stage–discharge curve derived through monitoring discharge in about 20 rivers or channels every year has been generally used. As revealed in many studies, however, the stage–discharge curve is inevitably affected by their hydraulic characteristics. This suggests that the use of a stage–discharge curve derived without considering hydraulic characteristics unique to a river or channel may produce significant errors in estimating discharge at not only low stage (during dry seasons) but also high stage (during flood seasons). In this study, the authors proposed a method to calculate the mean velocity and to estimate the discharge considering the hydraulic characteristics of a river or channel (e.g. the bed slope, wetted perimeter, width, kinematic viscosity, etc.); the method was developed using Chiu’s velocity equation. With the proposed method, it is possible to calculate a maximum velocity that is difficult to measure in an open channel, derive an entropy function representing the equilibrium of the channel, and thereby, estimate reliable discharge even in a flood season. To comparatively verify the utility of the proposed method, relations between the results of analysis using Manning’s and Chezy’s mean velocity equations and the values of measured discharge were addressed together. The results of analysis using lab data sets and measured data sets revealed that the proposed method was significantly more accurate in estimating discharge, even in flood seasons, when compared with the conventional method. 相似文献
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The present study focuses on the emergency response measures for landslide dams. This work presents a series of centrifuge model tests conducted on the draining processes of barrier dams that are based on the grain composition of the Tangjiashan landslide dam. The effects of diversion channels with trapezoid, triangular, and compound sections on the discharge, process, and size of the residual dam are discussed. The characteristics of the flow erosion during the process of discharge in the different channels are analyzed based on hydrodynamics. The results suggest that a diversion channel with a compound section has a higher initial discharge efficiency and lower peak flow, and the flow process curve corresponds to a “chunky-type.” The draining from this type of a diversion channel could clearly reduce the flood pressure of the river downstream and make the entire process smoother. Thus, the excavation of a diversion channel with a compound section is an efficient and safe method for landslide dam emergency mitigation. 相似文献
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针对缺乏地形条件和工程处置措施对堰塞坝溃决过程影响研究的现状,采用4种河床坡度（0°、1°、2°、3°）和3种泄流槽横断面型式（三角形、梯形、复合型）,开展了堰塞坝溃决的模型试验。通过分析堰塞坝的溃决流量、溃决历时、溃口发展和坝体纵截面演变过程,研究了不同河床坡度和泄流槽横断面对堰塞坝溃决过程的影响规律。试验结果表明：... 相似文献