A Calculation Method for Manning Roughness of Channels Containing Aquatic Plants

An aquatic plant, Manning roughness technology, applied in the direction of calculation, special data processing applications, instruments, etc., can solve problems such as many parameters, emphasis on mechanistic research, difficult application, etc., to achieve clear physical meaning, high engineering practical value, easy-to-get effects

Active Publication Date: 2018-09-14
CHINA INST OF WATER RESOURCES & HYDROPOWER RES
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Problems solved by technology

[0003] Although many scholars have conducted in-depth research on the water flow resistance of rivers containing aquatic plants, due to the complexity of the species, growth density and distribution of aquatic plants, most of the water flow resistance problems of rivers containing aquatic plants focus on mechanism research. , the Manning roughness formula proposed by different scholars from different angles still has certain limitations in engineering application, and there are many parameters to be calibrated, which are difficult to apply in actual engineering

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  • A Calculation Method for Manning Roughness of Channels Containing Aquatic Plants
  • A Calculation Method for Manning Roughness of Channels Containing Aquatic Plants
  • A Calculation Method for Manning Roughness of Channels Containing Aquatic Plants

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Embodiment 1

[0022] This embodiment is a method for calculating the Manning roughness of a water-bearing plant. The process of the method is as follows figure 1 Shown. This embodiment is mainly used in actual ecological river restoration projects or newly designed ecological channel projects. The steps of the method described in this embodiment are as follows:

[0023] (1) Steps to determine the basic Manning roughness coefficient of the river channel: used to find it from the hydraulic calculation manual or engineering design manual, or determine the basic Manning roughness coefficient of the river channel n 0 . In this embodiment, the existing Manning roughness coefficient is further refined, and more influencing factors are added to make it more able to reflect the real channel conditions. Therefore, first find out the basic Manning roughness coefficient of the river channel according to the material of the river bed from the manual (that is, the Manning roughness coefficient of the chan...

Embodiment 2

[0063] This embodiment is an improvement of the first embodiment, and is the calculation of the strength of the aquatic plants in the first embodiment. The calculation formula for the erection of aquatic plants in this embodiment is:

[0064] δ i =γ i Fr ωi .

[0065] The uprightness δ of aquatic plants is mainly determined by the Froude number of water flow, where γ is a coefficient that characterizes the resistance of plants to water flow impact, ω is an index that characterizes the resistance of plants to water flow impact, and γ and ω are dimensionless numbers, which are related to the types of plants. , It is a calibratable constant for fixed plant species. The subscript i of each letter represents the uprightness of various plants and aquatic plants.

Embodiment 3

[0067] This embodiment is an improvement of the second embodiment, and is the calculation of the strength of aquatic plants in the second embodiment. The calculation formula for the erection of aquatic plants in this embodiment is:

[0068] δ=0.33Fr -0.37 .

[0069] In some cases, the erection of aquatic plants cannot be observed on-site, so it can be obtained through the empirical formula of this embodiment.

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Abstract

The invention relates to a method for measuring a manning roughness coefficient of a river channel based on constant and non-uniform flows. The method comprises the following steps of setting a constraint condition; calculating a weight component of a control body along a flow direction; calculating dynamic water pressures withstood by river cross sections of an upstream and a downstream of the control body; calculating wetted perimeters of the river cross sections; calculating a comprehensive resistance value; establishing a momentum equation; and solving a comprehensive manning roughness coefficient. According to the method for measuring the comprehensive manning roughness coefficient of a natural river channel under the condition of the constant and non-uniform flows provided through theoretical analysis, various resistance values, such as a boundary resistance value of a river channel bed surface and an additional resistance value of plants, which are withstood by a water flow are comprehensively considered, the characteristics of the non-uniform flows of the water flow of the natural river channel are fully considered so that a measurement result accords with a real situation, and the manning roughness coefficient calculated according to the theory is accurate and meets the demand of practical design.

Description

Technical field [0001] The invention relates to a method for calculating the Manning roughness of a water-bearing plant in a river course, which is a hydraulic calculation method and a hydraulic method used for river course design. Background technique [0002] In recent years, with the enhancement of environmental protection awareness, river ecological protection and restoration technologies have developed rapidly around the world, and more and more ecological river construction projects have been implemented. As an important part of the river ecosystem, aquatic plants have become an important part of the construction of ecological rivers. Aquatic plants can provide habitats and food sources for organisms, inhibit the resuspension of sediment, and effectively improve water quality. At the same time, shore plants can prevent water from eroding the river bank, maintain the stability of the river bed and the meandering of the river. Compared with traditional river-type rivers, the...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G06F19/00
Inventor 穆祥鹏郑爽吴一红谢省宗白音包力皋许凤冉刘慧黄子一李想郭晓晨崔巍
Owner CHINA INST OF WATER RESOURCES & HYDROPOWER RES
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