Method for estimating shear stress of rectangular canal wall surface and bed surface

Abstract

The invention relates to a method for estimating shear stress of a rectangular canal wall surface and a bed surface. The method comprises the following steps: calculating the average shear stress of the bed surface; calculating the average shear stress of the wall surface; and calculating the ratio of a dragging force on the two side walls to a bed surface dragging force. According to the method disclosed by the invention, the average shear stress of the side wall and the bed surface is calculated by utilizing the section size, the hydraulic gradient and the width-depth ratio correction coefficient of the smooth rectangular canal, and the drag force of the water flow acting on the wall surface and the bed surface under the constant uniform flow condition can be accurately calculated. According to the method, the calculation precision of the average shear stress of the wall surface is improved to be within 7.5%, and the calculation precision is greatly improved. Compared with a traditional bed surface shear stress calculation method, the method has the advantages that the side wall effect is comprehensively considered, and the canal resistance coefficient and the riverbed erosion and deposition change can be analyzed more accurately. The method is convenient and simple, can be suitable for canals with different width-depth ratios, unifies wall surface shear stress calculation ofthe wide and shallow canals and the narrow and deep canals, and is wider in application range.

Description

technical field [0001] The invention relates to a method for estimating the shear stress of the wall surface and bed surface of a rectangular channel, which is a hydraulic calculation method and a method for analyzing the resistance of experimental water tanks and channels and studying sediment. Background technique [0002] The wall resistance and bed resistance of a rectangular channel are the basic elements of flume experiments and channel hydraulics research, the basis of channel resistance coefficient research, and the premise of sediment settlement and transport calculations. The shear stress distribution of the side wall and river bed of a rectangular channel is closely related to the flow velocity distribution of the section, the roughness of the side wall, the shape of the cross-section, and the secondary circulation. On-site measurement of the non-uniformity, side wall roughness, flow velocity and secondary circulation distribution of different sections of the cana...

AI Technical Summary

Problems solved by technology

The main disadvantages of this calculation method are: the artificial channel or the rectangular channel under the experimental conditions do not meet the assumption of wide and shallow channels, and the calculation error of the method ignoring the shear stress of the side wall is large, which cannot meet the needs of engineering design

However, the correlation between the corresponding coefficient revision method and the experimental data is poor, and it is impossible to use a unified equation to calculate the shear stress of the canal side wall and bed surface with different width-to-depth ratios.

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