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On the Total Flow Control Equations and Characteristics of Unsteady Gradually Varied Flow in Open Channels

  • Shi-he Liu (刘士和)Email author
  • Qian-yi Zhao (赵潜宜)
  • Qiu-shi Luo (罗秋实)
Article
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Abstract

Most unsteady channel flows in nature and practical engineering appear as gradually varied wherein the free surface deformation conforms to the long wave hypothesis. Currently one-dimensional total flow models are used to conduct numerical simulation of long-term and long-distance reaches to describe water movements, however, the models are insufficient to connect descriptions of flow field and total flow. Moreover, few studies of the variations of roughness coefficient change with time in unsteady flows have been conducted. The following results were obtained through theoretical analysis and numerical simulations in this paper. (1) One-dimensional total flow control equations of unsteady gradually varied flow in open channels were obtained directly from the mathematical model of viscous fluid motion, and can both reflect the influence of turbulence and provide an explicit expression of the energy slope item. These equations establish a direct connection between the descriptions of three-dimensional flow fields and one-dimensional total flows. (2) Synchronous prototype observation data and planar two-dimensional numerical simulation results were used to extract the one-dimensional total flow information and discuss the total flow characteristics. (3)The magnitude orders of items in the total flow motion equation were compared, and the change of the roughness coefficient with time was analyzed.

Key words

Open channel unsteady flow total flow characteristics control equations 

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Copyright information

© China Ship Scientific Research Center 2018

Authors and Affiliations

  • Shi-he Liu (刘士和)
    • 1
    Email author
  • Qian-yi Zhao (赵潜宜)
    • 1
  • Qiu-shi Luo (罗秋实)
    • 2
  1. 1.Key Laboratory of Water Resources and Hydropower Engineering ScienceWuhan UniversityWuhanChina
  2. 2.Yellow River Engineering Consulting Co., LtdZhengzhouChina

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