Renmin Zhujiang (Jan 2022)
Characteristics of Flow Field around Double Rectangular Piersin Tandem Based on RNG k-ε Turbulence Model
Abstract
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-ε 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.
