桥墩体型优化数值模拟

Numerical simulation of optimization of bridge pier shape

南水北调中线工程某段桥墩,水流流过桥墩后会在墩尾产生卡门涡街现象,涡的出现会增大水流阻力,影响输水渠道的过流能力。为了减小桥墩绕流阻力,增大渠道的过流能力,利用Fluent数值模拟软件对不同尾墩的桥墩进行数值模拟,并从流速、涡量、升阻力系数等方面对不同墩尾绕流进行分析。结果显示,随着墩尾流线半径(r)的增大,墩尾的绕流流动变的简单、流速波动降低、流线弯曲度减小、无明显的涡产生、桥墩的升阻力系数下降。综合结果分析,当r=9d时,桥墩对渠道的过流能力影响最小。

In a certain section of the middle route project of the South to North Water Diversion Project,the flow of water passing through the pier will generate a Karman vortex street phenomenon at the end of the pier.The appearance of the vortex will increase the flow resistance and affect the flow capacity of the water conveyance channel.In order to reduce the flow resistance around bridge piers and increase the flow capacity of the channel,Fluent numerical simulation software was used to simulate the flow around different tail piers,and the flow around different pier tails was analyzed from aspects such as flow velocity,vorticity,and lift resistance coefficient.The results show that as the radius(r)of the pier tail streamline increases,the flow around the pier tail becomes simpler;the flow velocity fluctuation decreases;the curvature of the streamline decreases;there are no obvious vortices generated;the lift resistance coefficient of the bridge pier decreases.The comprehensive results indicate that when r=9d,the pier has the smallest impact on the channel’s flow capacity.