共查询到18条相似文献，搜索用时 281 毫秒
1.
采用流量权重系数法推求断面平均含沙量法在长江干流水文站已应用,其原理源于部分流量加权法。通过对测站历年实测资料的分析计算,得到各取样垂线间的部分流量权重系数,如能满足规范的精度要求,则无须在悬移质输沙率测验中同步测流。利用垂线平均含沙量与垂线间部分流量权重系数的计算即可得到断面平均含沙量。运用此法能快速完成悬移质输沙率测验,减少流量测次,大幅降低生产成本,更能完整地掌握好含沙量测验过程,提高沙峰测验能力。 相似文献
2.
纪彭 《长江工程职业技术学院学报》2015,(2)
悬移质输沙率和流量异步施测,即进行悬移质输沙率测验不同时测流,根据测沙垂线的平均含沙量和部分流量权重系数计算断面平均含沙量。目前汉口站流量测验已实行水位流量关系单值化,该法可以大大减少流量测次,缩短测验历时,降低外业测验工作强度。 相似文献
3.
由垂线含沙量分布公式与流速指数分布公式的乘积得到垂线输沙率分布公式,据此对12种垂线平均输沙率计算方法进行了分析比较,并提出了改进意见。建议用辛普生九点法与高斯—勒让德四点法作为计算垂线平均输沙率近似真值的方法,其中后者不仅工作量小,精度高,还避免了施测底速底沙的难题。 相似文献
4.
积时式采样器较好地解决了以水文缆道为测验载体的悬移质输沙率测验问题.本文以汉江下游某站使用调压积时式采样器进行悬移质泥沙采样的方法为例,分析了该站现行取样方法存在的缺陷,对改进其取样方法进行了初步探讨.采用本研究方案,可以使悬移质含沙量测验精度得到一定的提高. 相似文献
5.
河流泥沙测验是各大流域主要测验项目之一。在确保河流泥沙测验资料精度的同时,对河流悬移质输沙率与流量测验进行异步分析,探讨其可行性,优化流量测次,节约生产成本,具有十分重要意义。 相似文献
6.
探讨ADCP测流条件下断面平均含沙量计算 总被引：2，自引：0，他引：2
崔效松 《长江工程职业技术学院学报》2007,24(1):20-21
水文测验技术的发展,对水文整编计算提出了新的问题,本文就如何利用ADCP测流设备的测验成果计算断面平均含沙量进行分析探讨,并通过多年实测资料的分析验证表明,在湖口水文站利用全断面混合法处理计算断面平均含沙量,能很好地解决ADCP测流中存在的问题. 相似文献
7.
以缆道为测验载体的水文站进行悬移质输沙率测验时,流速仪测流与调压积时式采样器取样分步进行,受流速脉动影响,悬移质取样容积不准确而影响测验成果精度。本文通过对控制悬移质取样的因素进行分析研究,提出了采用流速仪信号作为控制悬移质取样信息的取样方法,既解决了实现流速仪测流与调压积时式采样器取样同步进行的问题,又消除了流速脉动对积时式取样器取样容积精度的影响,完善了悬移质输沙率测验方案。 相似文献
8.
城陵矶水文断面位于洞庭湖出口水道上的城陵矶（七里山）。由于受下游约4km长江回水顶托影响,在高水位期经常出现断面流向紊乱、同垂线测点流向顺逆不定现象,给常规流量测验工作带来不便且引起较大的流量测验误差。本文着重阐述该断面出现流向紊乱的机制及为保证流量测验精度等需采取的对策。 相似文献
9.
王宝文 《杨凌职业技术学院学报》2011,10(1):60-61,65
为了解决魏家堡水文站高水流量测验问题,提高测验精度,探索电波流速仪在北方多泥沙河流的适用条件和适用范围。本文以渭河干流魏家堡水文站手持式电波流速仪与转子流速仪同步观测水面流速数据为依据,按照水文统计学原理进行计算、检查、分析两者之间的相关关系,率定电波流速仪测速应用系数,进而推求断面流量,解决电波流速仪用于渭河魏家堡站高水测验时的流量计算问题。 相似文献
10.
王武成 《延安教育学院学报》2011,25(4):100-101,112
通过对现有历史资料的分析,简化测验手段,提高工作效率,以腾出更多的人力和仪器设备等,更多更好地开展新站的水文测验和试验研究等各项工作。该文通过对神木水文站悬移质输沙率间测分析,为该站实行巡测提供技术支撑。以供相类似测站特性的水文站分析泥沙间测作参考。 相似文献
11.
Vertical distribution of sediment concentration 总被引：1，自引：0，他引：1
A simple formula is proposed to predict the vertical distribution of a suspended load concentration in a 2D steady turbulent flow. The proposed formula significantly improves the well-known Rouse formula where sediment concentration has an infinitely large value at the channel bottom and a zero value at the water surface. Based on this formula and the logarithmic velocity profile, a theoretical elementary function for the transport rate of a suspended load is developed. This equation improves the Einstein equation in which the unit-width suspended sediment discharge must be solved by numerical integration and a contradiction between the lower limit of the integral and that of velocity distribution exists. 相似文献
12.
激光粒度仪是施测泥沙颗粒级配分布的设备,在施测过程中以测试水体中悬浮物来确定泥沙颗粒级配的分布,并通过体积转换常数来计算含沙量。本文就LISST-100x现场激光粒度分析仪“泥沙体积转换常数”的计算方法进行分析探讨,以确定最优值的选择方法。 相似文献
13.
实验采用四步混凝法探讨油田回注水处理剂及其工艺流程。结果表明该水处理工艺简单,水处理剂成本低,流程改动少。处理后水中的悬浮固体、总铁和含油量分别达到2.0mg/L、0.43mg/L和1.4mg/L;硫酸盐还原菌和腐生菌均为102个/mL;浊度降到0.2Ntu;平均腐蚀率降到0.037mm/a;处理后水符合油田回注水水质标准,并且水质稳定。 相似文献
14.
Knowledge of the equilibrium bed-concentration is vital to mathematical modeling of the river-bed deformation associated with
suspended load but previous investigations only dealt with the reference concentration of uniform sediment because of difficulties
in observation of the bed-concentration. This work is a first attempt to develop a theoretical formula for the equilibrium
bed-concentration of any fraction of nonuniform sediment defined at the bed-surface. The formula is based on a stochastic-mechanistic
model for the exchange of nonuniform sediment near the bed, and described as a function of incipient motion probability, non-ceasing
probability, pickup probability, and the ratio of the average single-step continuous motion time to static time. Comparison
of bed-concentration calculated from the proposed formula with the measured data showed satisfactory agreement, indicating
the present formula can be used for solving the differential equation goverming the motion of suspended load.
Project supported by the National Natural Science Foundation of China (Nos. 59779010 and 50079025) 相似文献
15.
Wan Hanna Melini Wan Mohtar 《浙江大学学报(A卷英文版)》2017,18(11):882-894
Sediment dynamics are usually described in terms of the studies developed under a steady uniform flow, where the hydrodynamic forces are taken those pertaining to the mean time-averaged flow speed. However, the inherent turbulence plays an important role and should be considered implicitly in describing the complexity of turbulence effects in geophysical phenomena. This paper reviews the implementation of isolated turbulence, generated by oscillating grid on two important sediment transport phenomena, i.e., incipient sediment motion and suspension. The generated quasi-isotropic, laterally homogenous turbulence (that is, at a distance further away from the grid) permits an in-depth investigation of the effect of turbulent fluctuations and brings new insights in understanding both phenomena. The critical Shields profile for the incipient sediment motion characterized using the second order of turbulence statistics is qualitatively similar to the Shields curve obtained under a steady uniform flow. In the suspension of particles, there is a two-way interaction between sediment and turbulence. High concentration of suspended particles changes the turbulence structure and the presence of coherent vortices changes the particle settling velocity, which subsequently alters the concentration within the suspension layer. The studies of turbulence on incipient sediment motion and particle suspension provide a better understanding of the underlying physics of sediment behavior at the near-bed region. 相似文献
16.
介绍了声学多普勒流速剖面仪（ADCP）的原理。以重庆涪陵核电厂为例,论证了该仪器在内陆核电厂址水文观测中的适用性;根据河流水流状况选择对应的硬件配置,可快速高效对流速、流向进行观测。总结了应用中的成功经验,提出需要注意的问题,并对利用该仪器输出数据分析计算悬沙浓度分布剖面的可行性进行了探讨。 相似文献
17.
Numerous experiments have shown that the water flow in fine-grained soils can obey an exponential relationship at small gradients and a linear relationship when the hydraulic gradient exceeds a certain limit. Based on the non-Darcian flow described by exponent and threshold gradient, the theory of 1D consolidation is modified in this paper to consider a linear variation in the vertical total stress with depth and the effect of ramp loading. The numerical solutions were derived in detail by the finite difference method for excess pore water pressure and the average degree of consolidation. Finally, the influence of various parameters on consolidation behavior was investigated. The results show that the rate of consolidation is reduced when non-Darcian flow described by exponent and threshold gradient is adopted in the theory of 1D consolidation. As well the distribution of vertical total stress has a great influence on the dissipation of excess pore water pressure, either for pervious top and pervious bottom （PTPB） or for pervious top and impervious bottom （PTIB）. For the case of PTIB, the distribution of vertical total stress in a foundation has a great influence on the rate of consolidation; however, for the case of PTPB, the rate of consolidation is independent of the distribution of vertical total stress. The rate of consolidation is dependent on the ratio of the thickness of a soil layer to the equivalent head of the final average vertical total stress; the greater the value of this ratio, the slower the rate of consolidation. Finally, an increase in construction time reduces the consolidation rate of a foundation. Thus, consolidation behavior of 1D consolidation with non-Darcian flow has been thoroughly acquainted in this paper. 相似文献
18.
After the linear analytical method of unsteady flow theory is further improved, an innovative and faster algorithm is introduced. The water storage in a confined aquifer is derived from the water transmissivity coefficient and the water-pressure conductivity coefficient. The water transmissivity coefficient is approximated by a Taylorseries expansion of drawdown, and the water-pressure conductivity coefficient is obtained by the average drawdown. In this algorithm, the distance of the observation points from the pumping well must be short. When the distance is as short as the radius of the main pumping well, the data of the drawdown difference between the sidewall and the center of pumping well are difficult to measure, but the same results can be achieved based on the assumption that the drawdown difference approximates to the drawdown of the observation wells at a radial distance from the pumping well according to the algorithm. Without the help of charts, this algorithm is more concise and efficient, which has been verified by the test of water pumping project in Tianjin Binhai International Airport. 相似文献