An empirical generalization method for multi-parameter equivalent roughness of flow resistance around piers

Abstract

A multi-parameter empirical generalization method for the equivalent roughness of the flow resistance around piers, based on the basic flow resistance characteristics of bridge pier columns, through the measured flow velocity data of the cross-section of the river, the shadowing and interference between the columns of the turbulent mathematical model, the analysis, Introduce several parameters such as single-column flow resistance coefficient, single-column longitudinal shielding influence multiple, lateral interference influence multiple, flow velocity proportional coefficient, water-blocking area reduction coefficient, and water flow and bridge pier oblique coefficient to calculate the total flow resistance around the pier group and the corresponding The total resistance coefficient converts the total flow resistance of the pier group into the shear stress of the riverbed, and derives the equivalent roughness of the corresponding flow resistance of the pier. This simplifies the analysis of the impact of flood discharge on bridge groups in the overall one-dimensional hydrodynamic mathematical model of dense bridges and rivers, providing a basis for the establishment of bridge group backwater empirical formulas in the future, and making up for the lack of a dedicated analysis method for the total flow resistance of bridge pier groups.

Description

technical field [0001] The invention relates to a generalization method, in particular to an empirical generalization method for multi-parameter bridge pier flow resistance equivalent roughness. Background technique [0002] In the river section with dense bridges, when the upstream bridge is within the backwater range of the downstream bridge, its backwater height will increase due to the influence of the downstream bridge, especially for rivers with gentle slopes, the length of backwater influence is generally large, As a result, the backwater impact values ​​of multiple bridges will be superimposed, forming an iterative impact on river flood discharge. Therefore, changes in bridge spacing and river flood discharge in densely bridged river sections have received extensive attention from water administrative departments. However, the causes of water blocking in bridges fording river sections may be complex and changeable. The existing calculation formulas for backwater calc...

AI Technical Summary

Problems solved by technology

Finally, depending on the position of the pier, such as in a river channel or beach, the velocity of the water flow is different, and the submerged water depth is also different. Therefore, the flow resistance formed by each pier must be different, and it is difficult to use the ∑C in the formula d Directly calculate the total flow resistance coefficient around the pier, so a new technical solution is urgently needed to solve the problems faced by the existing technology

Images