Method for quantitatively defining a non-viscous bottom sand starting critical index

Abstract

The invention relates to a method for quantitatively defining a non-viscous bottom sand starting critical index. under the conditions of certain bed surface bottom sand and variable water flow, a high-speed camera is used for continuously shooting bed surface sediment images; color images continuously shot by the high-speed camera are preprocessed; obtaining the motion state of the sediment particles in each subdomain in the camera shooting area; identifying a moving subdomain in the camera shooting area; defining distribution characteristics of movement of silt in a camera shooting area, counting the sum of areas of all subdomains in which silt movement occurs, calculating the percentage of the subdomains in which silt is started in the camera shooting area, and taking water flow intensity when the percentage of the subdomains in which silt is started in the camera shooting area is 0 as a critical hydraulic index for defining bottom sand starting; According to the method, the bed surface sediment starting critical index can be accurately and quantitatively defined, the problem that the bottom sediment critical starting index is difficult to quantitatively define is solved, and thecritical index determined through the method can be conveniently expanded and applied to bed sediment starting observation under different water and sediment conditions.

Description

technical field [0001] The invention relates to a method for quantitatively defining the start-up critical index of non-cohesive bottom sand, which belongs to the technical field of water conservancy engineering. Background technique [0002] The critical hydraulic index condition of bottom sediment starting is an important part of the research on water and sediment movement in estuaries and coasts, and it is a hot spot of scientific research at the present stage. There are various ways to define the critical hydraulic index for conventional bottom sediment start-up. There are methods of reverse calculation by using the bottom sediment transport rate, and there is also a method of direct monitoring by high-speed camera technology. On the one hand, the measurement of mass and sediment load is difficult, and on the other hand, the accuracy is poor, so higher measurement accuracy can be obtained. However, in field monitoring, on the one hand, due to the complexity of the on-sit...

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Problems solved by technology

[0006] The invention provides a method for quantitatively defining the critical index of non-cohesive bottom sand start-up, which is suitable for most water flow conditions, including field surveys or indoor test backgrounds, and solves the difficulty of quantitatively defining non-cohesive sand start-up in complex water flow environments. The problem of critical hydraulic index

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