基于RNG k-ε湍流模型的串列双矩形截面桥墩绕流流场特性研究  

Characteristics of Flow Field around Double Rectangular Piers in Tandem Based on RNG k-ε Turbulence Model

作　　者：丁安娜 DING Anna(Qianshan County Water Conservancy Bureau,Shangrao 334599,China)

机构地区：[1]铅山县水利局,江西上饶334599

出　　处：《人民珠江》2022年第3期109-116,122,共9页Pearl River

摘　　要：串列双矩形截面桥墩在桥梁工程中应用广泛,桥墩间距对其绕流流场特性影响显著。利用Fluent软件,基于RNG k-?湍流模型对单矩形截面桥墩、串列双矩形截面桥墩绕流非稳态瞬时流场进行数值求解,从涡量、流线、压力及横向流速等多方面,研究了不同桥墩间距工况下(L/W=2、4、6)串列双矩形桥墩绕流流场分布特征。结果表明,与单矩形桥墩相比,串列双矩形桥墩绕流流动更复杂,尾流涡体及流线弯曲区横向分布范围更广;两桥墩剪切层的生成、分离和重附受桥墩间距影响,当L/W≥4时上游桥墩尾流出现涡体的生成与脱落,桥墩间形成流线弯曲区、压力增高区和压力降低区,下游桥墩尾流形成多个压力降低区。矩形桥墩尾流横向流速呈正负交替波动,与单桥墩单一且对称分布的流速波形图相比,双矩形桥墩横向流速波形图不再对称分布;桥墩间横向流速峰值随间距增大而降低,桥墩两侧区域横向流速波动峰值较单桥墩增大,且距离桥墩中心线越远波动峰值越低。研究结果可为桥墩布设提供参考。Double rectangular piers in tandem have been widely used in bridge engineering, and the distance between the two piers has a significant impact on the characteristics of the flow field around them.This paper utilized the Fluent software to simulate the unsteady instantaneous flow field around a single rectangular pier and double rectangular piers in tandem by using the RNG k-? turbulence model.The distribution characteristics of the flow field around the double rectangular piers in tandem at different distances(L/W=2,4,6) between the two piers were studied from the aspects of vorticity, streamline, pressure and transverse velocity.The results show that compared with that of the single rectangular pier, the fluid flow around the double rectangular piers in tandem is more complex and has wider lateral distributions of wake vortex and streamline bending zone.The generation, separation and reattachment of the shear layer of the two piers are affected by pier spacing.When L/W≥4,vortices are generated and fall off in the wake at the upstream pier.In such a case, the streamline bending zone, pressure increase zone and pressure decrease zone are formed between the two piers, and multiple pressure decrease zones are formed in the wake at the downstream pier.The transverse velocity of wakes at rectangular piers fluctuates between positive and negative.Compared with the single and symmetrical velocity waveform of the single pier, the transverse velocity waveform of the double rectangular piers is no longer symmetrically distributed.The peak transverse velocity between the two piers decreases with the increase in pier spacing, and the fluctuating peak values on both sides of the two piers are higher than those of the single pier.The fluctuating peak values are lower at a farther distance from the pier centerline.The research results can provide a reference for pier layout in bridge engineering.

关 键 词：矩形桥墩 RNG k-?湍流模型 流场特性 紊流 涡量 

分 类 号：O35[理学—流体力学]