...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Water resources research >Characterization of the hydraulics at natural step crests in step-pool streams via weir flow concepts
【24h】

Characterization of the hydraulics at natural step crests in step-pool streams via weir flow concepts

机译：通过堰流概念表征阶梯池流中自然阶梯波峰的水力学

获取原文
获取原文并翻译 | 示例
   

获取外文期刊封面封底 >>

       
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The hydraulics of step-pool streams are characterized by rapidly varied flow at the step crest, a hydraulic jump, and gradually varied flow in the pool unit of the step-pool sequence. The flow characteristics at the step crests act as the hydraulic control for the water surface profile within the upstream pool unit. Using both field and flume investigations, we demonstrate the use of weir flow concepts for assessing and categorizing the hydraulic characteristics of natural step-crests in step-pool streams. We categorize the results of our investigations in terms of the crest-clast, planform, longitudinal, and instream wood geometries of the step crests. The broad-crested weir equation can be expressed as Q = C~* g~(0.5)Wh~(3/2), where Q is the flowrate, C~* is a dimensionless discharge coefficient, W is the crest width, g is the acceleration of gravity, and h is the upstream flow depth above the step crest. Although the flow over a natural step is generally more complex than for an engineered weir, the results of our investigations indicate that the C~* -value for simulated and natural steps increases linearly as a function of the upstream head (h), with C~* values ranging from 0.15 to 0.97. As a result, the application of weir flow concepts to natural steps provides means for (1) indirectly estimating flow rates; (2) characterizing the hydraulics for individual steps; (3) defining external and/or internal boundary conditions at step crests for hydraulic model simulations of natural or restored step-pool streams; and (4) estimating the upstream pressure force acting on step-crest clasts.
机译：阶梯池水流的液压系统的特征在于，在阶梯波峰处的流量快速变化，水力跃变以及在阶梯池序列的池单元中流量逐渐变化。阶梯形波峰处的流动特性可作为上游池单元内水面轮廓的液压控制。通过现场和水槽调查，我们演示了堰流概念的使用，以对阶梯池流中天然阶梯波峰的水力特性进行评估和分类。我们根据阶梯波峰的波峰-碎屑，平面形状，纵向和入流木材几何形状对研究结果进行分类。宽顶堰方程可表示为Q = C〜* g〜（0.5）Wh〜（3/2），其中Q为流量，C〜*为无因次排放系数，W为波峰宽度，g是重力加速度，h是台阶顶部上方的上游流动深度。尽管自然步长的流量通常比工程堰的流量复杂，但我们的研究结果表明，模拟步长和自然步长的C〜*值随上游水头（h）线性增加，C 〜*值介于0.15到0.97之间。结果，将堰流概念应用于自然阶跃为（1）间接估算流速提供了手段。 （2）描述各个步骤的液压特性； （3）定义台阶顶的外部和/或内部边界条件，以对天然或恢复的台阶池水流进行水力模型模拟； （4）估算作用于阶梯波峰的上游压力。

著录项

  • 来源
    《Water resources research》 |2012年第9期|W09542.1-W09542.14|共14页
  • 作者

    David Dust; Ellen Wohl;

  • 作者单位

    Department of Geosciences, Colorado State University, Fort Collins,Colorado, USA;

    Department of Geosciences, Colorado State University, Fort Collins, CO 80523-1482, USA;

  • 收录信息
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号