Simulation of Local Scour Around A Bridge Pier Based on Different Turbulence Models and Formulae of Bedload Sediment Transport Rate

基於不同湍流模型與推移質輸沙率公式的橋墩局部沖刷數值模擬

ANBIN LI ； GENGUANG ZHANG ； AIMIN FAN ； ZHIYI HU ； HE SUN ； CHANDARA MAN

《台灣水利》 70卷1期 (2022/03) Pp. 94-109

https://doi.org/10.6937/TWC.202203_70(1).0008

摘要

This study evaluated the applicability of two turbulence models, namely the Large Eddy Simulation (LES) and Re-Normalization Group (RNG) k-ε models, and two bed load transport rate formulae, namely the Meyer-Peter and Van Rijn formulae, for the simulation of local scour around a pier, and the reasons causing the difference in simulation results are analyzed. The specific sediment transport rate formula used had a much greater effect on the simulation results than that of the turbulence model used, with the LES model combined with the Meyer-Peter formula showing the best performance in representing the vortex body structure, scour shape and depth, with a relative error of the maximum scour depth of only 2.3% at a scour time T = 30 min. In contrast, the simulation results based on the RNG k-ε model using the Meyer-Peter formula showed a larger relative error of 7.2%, and the combination of the LES model with the Van Rijn formula exhibited the largest relative error of 15.5%. The results of this study can act as a reference for the simulation of scour at a pier and can be particularly helpful in guiding the selection of appropriate turbulence models and sediment transport rate formulae in practical application. In addition, this study provides technical support for the safety design of bridges across rivers.

關鍵字

Local scour around a pier ； CFD ； RNG k-ε model ； LES model ； Bed load transport rate formula

並列摘要

本研究對兩種湍流模型（大渦模擬（LES）、重整化群（RNG k-ε））及兩個推移質輸沙率公式（Meyer-Peter和Van Rijn公式）在單圓柱橋墩局部繞流沖刷模擬中的適用性進行了分析評價，並就模擬結果間的差異原因進行了分析。結果表明：輸沙率公式對模擬結果的影響大於湍流模型；採用LES模型結合Meyer-Peter公式能較好地模擬橋墩繞流渦系結構及沖刷坑形態，當T＝30 min時，最大沖刷深度模擬結果與試驗結果相對誤差僅為2.3％；採用RNG k-ε模型結合Meyer-Peter公式預測的最大沖刷深度與試驗結果相對誤差為7.2％，LES模型結合Van Rijn公式的預測的最大沖刷深度與試驗結果相對誤差為15.5％；研究成果可為橋墩局部沖刷類比提供參考，並對實際應用中如何採用合適的湍流模型、輸沙率公式有一定的指導意義，為跨河橋樑的安全設計提供了理論支撐。

並列關鍵字

橋墩局部沖刷 ； RNG k-ε模型 ； LES模型 ； 推移質輸沙率公式

參考文獻

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