A alluvial reach flow resistance calculation model for the mainstream of the Yellow River based on energy slope partitioning method

Abstract

[Objective] Flow resistance characteristics are a core scientific issue in the field of river dynamics, with dual value in linking theoretical innovation and engineering practice. They not only provide theoretical support for revealing the mechanisms of water-sediment transport, but also serve as an important foundation for riverbed evolution simulation and flood control. The core objective is to clarify the applicability limitations of existing flow resistance formulas in the special water-sediment environment of the Yellow River, establish a resistance calculation method suitable for the condition of strong scouring and silting of fine particles, and provide technical support for the accurate simulation of riverbed evolution in the Yellow River. [Methods] Firstly, existing flow resistance formulas were systematically reviewed, and relevant formulas based on resistance partitioning were verified. Aiming at the significant deviation problem of verified formulas under the condition of strong scouring and silting of fine particles, the idea of energy slope partitioning was adopted, and a formula framework with the superposition of sand grain resistance and sand wave resistance as the core was constructed. Coefficients in the calculation formulas of sand wave length and height were calibrated through measured data, and a flow resistance formula for the Yellow River based on the energy slope partitioning method was established. The relationship between coefficients and Froude number(Fr) was calibrated using observed data. Finally, the accuracy of the newly established formula and the rationality of the parameters were verified and analyzed through measured data. [Results] Verification result showed that the newly established flow resistance formula had high accuracy, and the calculated result of sand wave height, sand wave length, and the proportion of sand wave resistance were all within reasonable ranges. The resistance coefficient showed a significant negative correlation with the measured sediment-carrying capacity. The calculation result of the formula were consistent with the automatic adjustment pattern of the Yellow River channel, and enabled the reasonable simulation of riverbed evolution in the Yellow River. [Conclusion] It is confirmed that the flow resistance formula constructed based on the energy slope partitioning method can effectively adapt to the special water-sediment environment of strong scouring and silting of fine particles in the Yellow River, and solve the problem of insufficient applicability of traditional formulas in this scenario. The established formula can be used as an effective calculation method for flow resistance in the Yellow River, and provide reliable technical support for the simulation of riverbed evolution in the Yellow River and related engineering practices of flood control.

Keywords

flow resistance / Yellow River / energy slope partitioning / riverbed morphology / influencing factors / sediment / water-sediment environment / riverbed evolution