Method of generalizing around-pier flow drag equivalent roughness based on upstream and downstream bridge level differences

Abstract

A method of generalizing around-pier flow drag equivalent roughness based on upstream and downstream bridge level differences comprises: establishing first to third view sections at the upstream of apier, the pier and the downstream of the pier according to levels Z1, Z2 and Z3 of the first to third view sections, cross-sectional areas A1, A2 and A3, natural riverway roughness n and flow quantityQ, calculating local head loss coefficient Zeta s caused by bridge-front flow contraction and under-bridge flow narrowing, local head loss Zeta e caused by bridge-rear flow diffusion and the like, and frictional head loss hf, calculating local head loss hjF caused by around-pier flow drag, and reversely deducting around-pier flow drag equivalent roughness nt. Starting with the analysis of local head loss and frictional head loss, the method of inverting around-pier flow drag equivalent roughness is constructed; the equivalent roughness that is generalized is applicable to the empirical calculation, numerical simulation and physical model test for superposed backwater after bridge clustering, and verification data can be provided for the pier drag generalizing method.

Description

technical field [0001] The invention relates to a generalization method for equivalent roughness, in particular to a generalization method for equivalent roughness of flow resistance around piers based on the water level difference between upstream and downstream of bridges. Background technique [0002] "Equivalent" generally means that different physical phenomena, models, processes, etc. have the same physical meaning, effect or physical law. For the research in the field of hydraulic engineering, "equivalent" is a commonly used research method, which is to change the research angle of the problem under the premise that the physical effects are similar or the same, and replace the more complex factors with simpler factors, so that Unfamiliar and complex problems are converted into familiar and easy-to-handle problems, and the simplified solutions to difficult water conservancy problems are promoted. As far as problems related to river channel roughness are concerned, the...

AI Technical Summary

Problems solved by technology

However, there is a huge difference between the bridge pier scale and the river channel scale, and the layout of the calculation grid is very difficult. Although there is an equivalent generalization method proposed by the above-mentioned scholars, further data support is still needed to ensure the consistency before and after the generalization

Therefore, there is an urgent need for a new technology solution based on prototype observation technology to provide practical problems such as lack of verification data faced by existing technologies.

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